phase3: nullfix.py batch script — bang/late/param-nullable

Automated null-safety fixes driven by dart analyze (no corruption):
- unchecked_use_of_nullable_value: insert '!' on receiver (property/method/[]/op)
- not_initialized field/var: mark 'late'
- missing_default_value_for_parameter: nullable param
Errors: 2374(peak) -> 907

lib/pages/buy_service.dart

@@ -30,7 +30,7 @@ class BuyService extends StatefulWidget {
 }
 
 class BuyServiceState extends State<BuyService> {
-  Map<String, dynamic> data;
+  late Map<String, dynamic> data;
 
   @override
   Widget build(BuildContext context) {

lib/pages/contact_us.dart

@@ -22,7 +22,7 @@ class ContactUs extends StatefulWidget {
 }
 
 class ContactUsState extends State<ContactUs> {
-  Business business;
+  late Business business;
 
   @override
   Widget build(BuildContext context) {

lib/pages/download.dart

@@ -30,7 +30,7 @@ class Download extends StatefulWidget {
 
 class DownloadState extends State<Download> {
   final _scaffoldKey = GlobalKey<ScaffoldState>();
-  Map<String, dynamic> data;
+  late Map<String, dynamic> data;
 
   @override
   Widget build(BuildContext context) {
@@ -79,7 +79,7 @@ class DownloadState extends State<Download> {
     super.initState();
     eventBus.on<OpenDrawer>().listen((event) {
       if (mounted) {
-        _scaffoldKey.currentState.openDrawer();
+        _scaffoldKey.currentState!.openDrawer();
       }
     });
     _loadData();

lib/pages/igoshow_learn_more.dart

@@ -26,7 +26,7 @@ class IGoShowLearnMore extends StatefulWidget {
 
 class IGoShowLearnMoreState extends State<IGoShowLearnMore> {
   final _scaffoldKey = GlobalKey<ScaffoldState>();
-  Map<String, dynamic> data;
+  late Map<String, dynamic> data;
 
   @override
   Widget build(BuildContext context) {

lib/pages/minipos_learn_more.dart

@@ -26,7 +26,7 @@ class MiniPosLearnMore extends StatefulWidget {
 
 class MiniPosLearnMoreState extends State<MiniPosLearnMore> {
   final _scaffoldKey = GlobalKey<ScaffoldState>();
-  Map<String, dynamic> data;
+  late Map<String, dynamic> data;
 
   @override
   Widget build(BuildContext context) {

lib/pages/plain_page.dart

@@ -23,7 +23,7 @@ class PlainPage extends StatefulWidget {
 }
 
 class PlainPageState extends State<PlainPage> {
-  Blog blog;
+  late Blog blog;
 
   @override
   Widget build(BuildContext context) {

lib/pages/renew_minioffice.dart

@@ -25,7 +25,7 @@ class RenewMiniOffice extends StatefulWidget {
 }
 
 class RenewMiniOfficeState extends State<RenewMiniOffice> {
-  Map<String, dynamic> data;
+  late Map<String, dynamic> data;
 
   @override
   Widget build(BuildContext context) {

lib/utils/double_back_to_close_app.dart

@@ -34,7 +34,7 @@ class DoubleBackToCloseApp extends StatefulWidget {
 
 class _DoubleBackToCloseAppState extends State<DoubleBackToCloseApp> {
   /// The last time the user tapped Android's back-button.
-  DateTime _lastTimeBackButtonWasTapped;
+  late DateTime _lastTimeBackButtonWasTapped;
 
   /// Returns whether the current platform is Android.
   bool get _isAndroid => Theme.of(context).platform == TargetPlatform.android;
@@ -59,7 +59,7 @@ class _DoubleBackToCloseAppState extends State<DoubleBackToCloseApp> {
   /// local-history of the current route, in order to handle pop. This is done
   /// by [Drawer], for example, so it can close on pop.
   bool get _willHandlePopInternally =>
-      ModalRoute.of(context).willHandlePopInternally;
+      ModalRoute.of(context)!.willHandlePopInternally;
 
   @override
   Widget build(BuildContext context) {

lib/utils/http_util.dart

@@ -35,8 +35,8 @@ class HttpUtil {
     'Http-Contact-Authorization': '',
     'Http-Device-Type': Utils.getOs(checkWeb: true),
     'Http-Api-Branch': 'flutter',
-    'Http-Language-Code': store.state.locale.languageCode,
-    'Http-Country-Code': store.state.locale.countryCode ?? '',
+    'Http-Language-Code': store.state.locale!.languageCode,
+    'Http-Country-Code': store.state.locale!.countryCode ?? '',
   };
 
   static Future<dynamic> httpGet(String url,

lib/utils/util_io.dart

@@ -199,8 +199,8 @@ class Util {
     return box;
   }
 
-  static Widget showImage(String imageUrl, {double width, double height,
-    BoxFit fit, Widget Function(BuildContext, String, dynamic) errorWidget}) {
+  static Widget showImage(String imageUrl, {double? width, double? height,
+    BoxFit? fit, Widget Function(BuildContext, String, dynamic)? errorWidget}) {
     if (imageUrl != null && imageUrl.isNotEmpty && imageUrl.startsWith('https:')) {
       return CachedNetworkImage(
         imageUrl: imageUrl,
@@ -317,14 +317,14 @@ class Util {
     final picker = ImagePicker();
     var image = await picker.pickImage(source: ImageSource.gallery);
     Navigator.of(context).pop();
-    uploadPicture(context, File(image.path), user, commentId: commentId, orderId: orderId);
+    uploadPicture(context, File(image!.path), user, commentId: commentId, orderId: orderId);
   }
 
   void getPictureFromCamera(BuildContext context, User user, {int commentId = -1, int orderId = 0}) async {
     final picker = ImagePicker();
     var image = await picker.pickImage(source: ImageSource.camera);
     Navigator.of(context).pop();
-    uploadPicture(context, File(image.path), user, commentId: commentId, orderId: orderId);
+    uploadPicture(context, File(image!.path), user, commentId: commentId, orderId: orderId);
   }
 
   void uploadPicture(BuildContext context, File image, User user, {int commentId = -1, int orderId = 0}) async {
@@ -454,18 +454,18 @@ class Util {
     ImagePicker picker = ImagePicker();
     var image = await picker.pickImage(source: ImageSource.gallery);
     Navigator.of(context).pop();
-    onGotFile(imageId, image.path);
+    onGotFile(imageId, image!.path);
   }
 
   void getPictureFromCamera2(BuildContext context, int imageId, OnGotFile onGotFile) async {
     ImagePicker picker = ImagePicker();
     var image = await picker.pickImage(source: ImageSource.camera);
     Navigator.of(context).pop();
-    onGotFile(imageId, image.path);
+    onGotFile(imageId, image!.path);
   }
 
   Future<void> createTicket(BuildContext context, String msg, List<Map<String, dynamic>> images,
-      OnSuccess onSuccess, OnError onError, {int id}) {
+      OnSuccess onSuccess, OnError onError, {int? id}) {
     var formData = FormData();
     formData.fields.add(MapEntry("msg", msg));
     formData.fields.add(MapEntry('id', id == null ? '0' : id.toString()));
@@ -555,6 +555,6 @@ class Util {
     ByteData data = await rootBundle.load(path);
     ui.Codec codec = await ui.instantiateImageCodec(data.buffer.asUint8List(), targetWidth: width);
     ui.FrameInfo fi = await codec.getNextFrame();
-    return (await fi.image.toByteData(format: ui.ImageByteFormat.png)).buffer.asUint8List();
+    return (await fi.image.toByteData(format: ui.ImageByteFormat.png))!.buffer.asUint8List();
   }
 }

lib/widgets/desktop/create_online_store_1.dart

@@ -35,12 +35,12 @@ class CreateOnlineStore1State extends State<CreateOnlineStore1> {
   bool canSubmit = false;
 
   List<dynamic> stores = [];
-  Map<String, dynamic> service;
+  late Map<String, dynamic> service;
   dynamic selectedStore;
 
-  Group group;
+  late Group group;
 
-  String selectedDomain;
+  late String selectedDomain;
   List<dynamic> domainResult = [];
 
   @override
@@ -284,7 +284,7 @@ class CreateOnlineStore1State extends State<CreateOnlineStore1> {
                     ),
                     autofocus: true,
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         return S.of(context).domains_separated_comma;
                       }
                       return null;

lib/widgets/desktop/desktop_blog.dart

@@ -34,7 +34,7 @@ class DesktopBlog extends StatefulWidget {
 }
 
 class DesktopBlogState extends State<DesktopBlog> {
-  List<Blog> blogs;
+  late List<Blog> blogs;
 
   double division = 2;
 

lib/widgets/desktop/desktop_buy_service.dart

@@ -27,7 +27,7 @@ class DesktopBuyServiceState extends State<DesktopBuyService> {
   double mainSpace = 1200;
 
   List<KeyValue> plans = [];
-  KeyValue selectedPlan;
+  late KeyValue selectedPlan;
   double price = 0.0;
   double tax = 0.0;
   double paymentAmount = 0.0;

lib/widgets/desktop/desktop_change_mobile_or_email.dart

@@ -32,9 +32,9 @@ class DesktopChangeMobileOrEmailState extends State<DesktopChangeMobileOrEmail>
   bool usernameEnable = true;
   final codeController = TextEditingController();
 
-  bool enableGetCode;
-  String getCodeText;
-  bool canRegister;
+  late bool enableGetCode;
+  late String getCodeText;
+  late bool canRegister;
 
   var countDownListener;
 
@@ -88,7 +88,7 @@ class DesktopChangeMobileOrEmailState extends State<DesktopChangeMobileOrEmail>
                     ),
                     autofocus: true,
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         if (widget.isMobile) {
                           return S
                               .of(context)
@@ -99,10 +99,10 @@ class DesktopChangeMobileOrEmailState extends State<DesktopChangeMobileOrEmail>
                               .email_is_required;
                         }
                       }
-                      if (widget.isMobile && value.trim() == store.state.user.mobile) {
+                      if (widget.isMobile && value!.trim() == store.state.user!.mobile) {
                         return S.of(context).the_mobile_number_is_same_as_current;
                       }
-                      if (!widget.isMobile && value.trim() == store.state.user.email) {
+                      if (!widget.isMobile && value!.trim() == store.state.user!.email) {
                         return S.of(context).the_email_is_same_as_current;
                       }
                       return null;
@@ -185,7 +185,7 @@ class DesktopChangeMobileOrEmailState extends State<DesktopChangeMobileOrEmail>
                         fontSize: 18.0
                     ),
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         return S.of(context).verification_code_is_required;
                       }
                       return null;
@@ -332,7 +332,7 @@ class DesktopChangeMobileOrEmailState extends State<DesktopChangeMobileOrEmail>
         },
         isFormData: true,
         body: {
-          'id': store.state.user.id,
+          'id': store.state.user!.id,
           'mobile': usernameController.text.trim(),
           'code': codeController.text.trim(),
         },
@@ -344,8 +344,8 @@ class DesktopChangeMobileOrEmailState extends State<DesktopChangeMobileOrEmail>
 
   void getCodeTapped() {
     if (usernameController.text.isNotEmpty &&
-        ((widget.isMobile && usernameController.text.trim() != store.state.user.mobile) ||
-            (!widget.isMobile && usernameController.text.trim() != store.state.user.email))) {
+        ((widget.isMobile && usernameController.text.trim() != store.state.user!.mobile) ||
+            (!widget.isMobile && usernameController.text.trim() != store.state.user!.email))) {
       HttpUtil.httpPost('v1/users', (response) {
         Fluttertoast.showToast(
             msg: S.of(context).verification_code_sent,
@@ -366,7 +366,7 @@ class DesktopChangeMobileOrEmailState extends State<DesktopChangeMobileOrEmail>
           'action': 'change_mobile_email_send_code'
         },
         body: {
-          'id': store.state.user.id,
+          'id': store.state.user!.id,
           'mobile': usernameController.text,
         },
         isFormData: true,
@@ -384,9 +384,9 @@ class DesktopChangeMobileOrEmailState extends State<DesktopChangeMobileOrEmail>
         errorMsg = S.of(context).mobile_is_required;
       } else if (!widget.isMobile && usernameController.text.trim().isEmpty) {
         errorMsg = S.of(context).email_is_required;
-      } else if (widget.isMobile && usernameController.text.trim() == store.state.user.mobile) {
+      } else if (widget.isMobile && usernameController.text.trim() == store.state.user!.mobile) {
         errorMsg = S.of(context).the_mobile_number_is_same_as_current;
-      } else if (!widget.isMobile && usernameController.text.trim() == store.state.user.email) {
+      } else if (!widget.isMobile && usernameController.text.trim() == store.state.user!.email) {
         errorMsg = S.of(context).the_email_is_same_as_current;
       }
       Fluttertoast.showToast(

lib/widgets/desktop/desktop_change_password.dart

@@ -24,10 +24,10 @@ class DesktopChangePasswordState extends State<DesktopChangePassword> {
   final passwordController = TextEditingController();
   final passwordAgainController = TextEditingController();
 
-  bool passwordVisible;
-  bool passwordAgainVisible;
+  late bool passwordVisible;
+  late bool passwordAgainVisible;
 
-  bool canReset;
+  late bool canReset;
 
   double sideSpace = 0;
   double mainSpace = 1200;
@@ -138,7 +138,7 @@ class DesktopChangePasswordState extends State<DesktopChangePassword> {
                                         fontSize: 18.0
                                     ),
                                     validator: (String? value) {
-                                      if (value.trim().isEmpty) {
+                                      if (value!.trim().isEmpty) {
                                         return S.of(context).current_password_is_required;
                                       }
                                       return null;
@@ -192,7 +192,7 @@ class DesktopChangePasswordState extends State<DesktopChangePassword> {
                                         fontSize: 18.0
                                     ),
                                     validator: (String? value) {
-                                      if (value.trim().isEmpty) {
+                                      if (value!.trim().isEmpty) {
                                         return S.of(context).password_is_required;
                                       }
                                       return null;
@@ -246,10 +246,10 @@ class DesktopChangePasswordState extends State<DesktopChangePassword> {
                                         fontSize: 18.0
                                     ),
                                     validator: (String? value) {
-                                      if (value.trim().isEmpty) {
+                                      if (value!.trim().isEmpty) {
                                         return S.of(context).password_is_required;
                                       }
-                                      if (value.trim() != passwordController.text.trim()) {
+                                      if (value!.trim() != passwordController.text.trim()) {
                                         return S.of(context).password_is_not_match_password_again;
                                       }
                                       return null;
@@ -338,7 +338,7 @@ class DesktopChangePasswordState extends State<DesktopChangePassword> {
           },
           isFormData: true,
           body: {
-            'id': store.state.user.id,
+            'id': store.state.user!.id,
             'old_password': oldPasswordController.text.trim(),
             'password': passwordController.text.trim(),
           }

lib/widgets/desktop/desktop_checkout.dart

@@ -222,7 +222,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                   mainAxisAlignment: MainAxisAlignment.spaceBetween,
                   children: [
                     Text(
-                      '\$${(cartInfo.totalPrice - couponDiscountAmount).toStringAsFixed(2)}',
+                      '\$${(cartInfo.totalPrice! - couponDiscountAmount).toStringAsFixed(2)}',
                       style: TextStyle(
                         fontSize: 20.0,
                         color: Colors.white,
@@ -292,7 +292,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
       itemCount: 6,
       addAutomaticKeepAlives: true,
       itemBuilder: (BuildContext context, int position) {
-        var deliveryTimeInSeconds = cartInfo.businessInfo.shippingTime * 60 + (durationInTraffic != null ? durationInTraffic.value : 0);
+        var deliveryTimeInSeconds = cartInfo!.businessInfo!.shippingTime! * 60 + (durationInTraffic != null ? durationInTraffic!.value : 0);
         print('aaa: $deliveryTimeInSeconds');
         DateTime now = DateTime.now();
         var formatter = DateFormat('H:mm');
@@ -366,7 +366,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
         );
         switch (position) {
           case 0:
-            if (cartInfo.businessInfo.deliveryPickup) {
+            if (cartInfo!.businessInfo!.deliveryPickup) {
               return Container(
                 padding: EdgeInsets.only(
                     top: 16.0, bottom: 16.0, left: 16.0, right: 16.0),
@@ -380,8 +380,8 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                 ),
                 child: Container(
                   alignment: Alignment.centerLeft,
-                  child: store.state.deviceId != null && store.state.deviceId.isNotEmpty ? (
-                      store.state.tableNumber != null && store.state.tableNumber.isNotEmpty ?
+                  child: store.state.deviceId != null && store.state.deviceId!.isNotEmpty ? (
+                      store.state.tableNumber != null && store.state.tableNumber!.isNotEmpty ?
                       peopleCountSelection :
                       SizedBox.shrink()
                   ) : Center(child: toggleSwitch,),
@@ -394,8 +394,8 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
             }
             break;
           case 1:
-            if (store.state.deviceId != null && store.state.deviceId.isNotEmpty ||
-                store.state.tableNumber != null && store.state.tableNumber.isNotEmpty) {
+            if (store.state.deviceId != null && store.state.deviceId!.isNotEmpty ||
+                store.state.tableNumber != null && store.state.tableNumber!.isNotEmpty) {
               return SizedBox.shrink();
             }
             if (deliveryMethod == 'pickup') {
@@ -414,7 +414,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                     Container(
                       margin: EdgeInsets.only(top: 10.0),
                       child: Text(
-                        cartInfo.businessInfo.name,
+                        cartInfo!.businessInfo!.name,
                         style: TextStyle(
                           fontSize: 17.0,
                         ),
@@ -423,7 +423,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                     Container(
                       margin: EdgeInsets.only(top: 5.0),
                       child: Text(
-                        cartInfo.businessInfo.address.addressLine1,
+                        cartInfo!.businessInfo!.address!.addressLine1,
                         style: TextStyle(
                           fontSize: 14.0,
                           color: Colors.black45,
@@ -431,9 +431,9 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                       ),
                     ),
                     Container(
-                      child: cartInfo.businessInfo.address.addressLine2 != null
-                          && cartInfo.businessInfo.address.addressLine2.length > 0 ?
-                      Text(cartInfo.businessInfo.address.addressLine2,
+                      child: cartInfo!.businessInfo!.address!.addressLine2 != null
+                          && cartInfo!.businessInfo!.address!.addressLine2!.length > 0 ?
+                      Text(cartInfo!.businessInfo!.address!.addressLine2,
                         style: TextStyle(
                           fontSize: 14.0,
                           color: Colors.black45,
@@ -442,7 +442,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                     ),
                     Container(
                       child: Text(
-                        '${cartInfo.businessInfo.address.city}, ${cartInfo.businessInfo.address.state}, ${cartInfo.businessInfo.address.zip}',
+                        '${cartInfo!.businessInfo!.address!.city}, ${cartInfo!.businessInfo!.address!.state}, ${cartInfo!.businessInfo!.address!.zip}',
                         style: TextStyle(
                           fontSize: 14.0,
                           color: Colors.black45,
@@ -452,7 +452,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                     Container(
                       margin: EdgeInsets.only(top: 5.0),
                       child: Text(
-                        'Tel: ${cartInfo.businessInfo.phone}',
+                        'Tel: ${cartInfo!.businessInfo!.phone}',
                         style: TextStyle(
                           fontSize: 15.0,
                           color: Colors.black54,
@@ -494,7 +494,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                           children: <Widget>[
                             Container(
                               child: Text(
-                                shipAddress != null ? shipAddress.fullAddress : S.of(context).enter_delivery_address,
+                                shipAddress != null ? shipAddress!.fullAddress : S.of(context).enter_delivery_address,
                                 style: TextStyle(
                                     fontSize: 16.0
                                 ),
@@ -505,7 +505,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                             Container(
                               padding: EdgeInsets.only(top: 6.0),
                               child: Text(
-                                shipAddress != null ? shipAddress.contactName + ' ' + shipAddress.phone : '',
+                                shipAddress != null ? shipAddress!.contactName! + ' ' + shipAddress!.phone : '',
                                 style: TextStyle(
                                   fontSize: 14.0,
                                   color: Colors.black38,
@@ -529,13 +529,13 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                 ),
               ),
               onTap: () {
-                Routes.router.navigateTo(context, '/my-addresses/${cartInfo.businessInfo.id}', replace: true);
+                Routes.router.navigateTo(context, '/my-addresses/${cartInfo!.businessInfo!.id}', replace: true);
               },
             );
             break;
           case 2:
-            if (deliveryMethod == 'pickup' || store.state.deviceId != null && store.state.deviceId.isNotEmpty ||
-                store.state.tableNumber != null && store.state.tableNumber.isNotEmpty) {
+            if (deliveryMethod == 'pickup' || store.state.deviceId != null && store.state.deviceId!.isNotEmpty ||
+                store.state.tableNumber != null && store.state.tableNumber!.isNotEmpty) {
               return SizedBox.shrink();
             }
             if (deliveryMethod == 'canada-post') {
@@ -578,7 +578,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                                   alignment: Alignment.centerRight,
                                   child: Text(
                                       selectedShippingRate != null ?
-                                    '${selectedShippingRate.name} \$${selectedShippingRate.price.toStringAsFixed(2)}' :
+                                    '${selectedShippingRate!.name} \$${selectedShippingRate!.price!.toStringAsFixed(2)}' :
                                     S.of(context).please_select,
                                     style: TextStyle(
                                       fontSize: 15.0,
@@ -608,7 +608,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                 },
               );
             }
-            if (!cartInfo.businessInfo.instanceDelivery) {
+            if (!cartInfo!.businessInfo!.instanceDelivery) {
               return Container(
                 padding: EdgeInsets.only(left: 16.0, right: 16.0, top: 0.0, bottom: 16.0),
                 child: Text(S.of(context).no_instance_delivery_desc),
@@ -654,7 +654,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                             child: Text(
                               bookingTimeList.length > 0 ? '${Utils.timestampToString(context, bookingTimeList[bookingTimeIndex].unixTime)}'
                                   : ((bookingTimeList.length == 0 && bookingDateTimeList.length == 0) ? ''
-                                  : bookingDateTimeList[bookingDateIndex].viewDate + ' ' + (bookingDateTimeList[bookingDateIndex].bookTimes.length > 0 ? bookingDateTimeList[bookingDateIndex].bookTimes[bookingTimeIndex].viewTime : '')),
+                                  : bookingDateTimeList[bookingDateIndex].viewDate! + ' ' + (bookingDateTimeList[bookingDateIndex].bookTimes!.length > 0 ? bookingDateTimeList[bookingDateIndex].bookTimes![bookingTimeIndex].viewTime : '')),
                             ),
                           ),
                           Container(
@@ -737,7 +737,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
               width: double.infinity,
               padding: EdgeInsets.only(bottom: 10.0),
               child: Text(
-                cartInfo.businessInfo.name,
+                cartInfo!.businessInfo!.name,
                 overflow: TextOverflow.ellipsis,
                 style: TextStyle(
                   fontSize: 16.0,
@@ -756,9 +756,9 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
 
             subtotal = 0.0;
 
-            for (var i = 0; i < cartInfo.productList.length; i++) {
-              subtotal += cartInfo.productList[i].totalPrice;
-              column.children.add(lineItem(cartInfo.productList[i]));
+            for (var i = 0; i < cartInfo!.productList!.length; i++) {
+              subtotal += cartInfo!.productList![i].totalPrice;
+              column.children.add(lineItem(cartInfo!.productList![i]));
             }
             column.children.add(GestureDetector(
               child: Container(
@@ -851,8 +851,8 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
               ),
             ));
 
-            if (cartInfo.extraFeeList.length > 0) {
-              for (var i = 0; i < cartInfo.extraFeeList.length; i++) {
+            if (cartInfo!.extraFeeList!.length > 0) {
+              for (var i = 0; i < cartInfo!.extraFeeList!.length; i++) {
                 column.children.add(Container(
                   padding: EdgeInsets.only(bottom: 16.0),
                   alignment: Alignment.centerRight,
@@ -863,7 +863,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                       Container(
                         alignment: Alignment.centerRight,
                         child: Text(
-                          S.of(context).extra_fee_token(cartInfo.extraFeeList[i].name, cartInfo.extraFeeList[i].rate),
+                          S.of(context).extra_fee_token(cartInfo!.extraFeeList![i].name, cartInfo!.extraFeeList![i].rate),
                           style: TextStyle(
                             color: Colors.grey,
                           ),
@@ -873,7 +873,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                         width: 100.0,
                         alignment: Alignment.centerRight,
                         child: Text(
-                            '${cartInfo.extraFeeList[i].price.toStringAsFixed(2)}'
+                            '${cartInfo!.extraFeeList![i].price!.toStringAsFixed(2)}'
                         ),
                       ),
                     ],
@@ -901,7 +901,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                     width: 100.0,
                     alignment: Alignment.centerRight,
                     child: Text(
-                      '${(cartInfo.totalPrice - couponDiscountAmount).toStringAsFixed(2)}',
+                      '${(cartInfo!.totalPrice! - couponDiscountAmount).toStringAsFixed(2)}',
                       style: TextStyle(
                         fontSize: 19.0,
                         fontWeight: FontWeight.bold,
@@ -999,7 +999,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
         children: <Widget>[
           Container(
             padding: EdgeInsets.all(5.0),
-            child: Util.showImage('${cartLineItem.product.imagePath}',
+            child: Util.showImage('${cartLineItem.product!.imagePath}',
               width: 80.0,
               height: 80.0,
               fit: BoxFit.fill,
@@ -1036,14 +1036,14 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
             alignment: Alignment.centerRight,
             margin: EdgeInsets.only(right: 10.0),
             child: Text(
-              'x${cartLineItem.quantity.round()}',
+              'x${cartLineItem.quantity!.round()}',
             ),
           ),
           Container(
             width: 60.0,
             alignment: Alignment.centerRight,
             child: Text(
-              '${cartLineItem.totalPrice.toStringAsFixed(2)}',
+              '${cartLineItem.totalPrice!.toStringAsFixed(2)}',
             ),
           ),
         ],
@@ -1099,7 +1099,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
           shippingRates = (response.data['shipping_rates'] as List).map((e) => ShippingRate.fromJson(e)).toList();
           selectedShippingRate = (response.data['selected_shipping_rate'] as String).length > 0 ? ShippingRate.fromJson(json.decode(response.data['selected_shipping_rate'])) : null;
           int i = 0;
-          if (cartInfo.businessInfo.deliveryStoreDelivery) {
+          if (cartInfo!.businessInfo!.deliveryStoreDelivery) {
             shippingMethodLabels.add(S.of(context).delivery);
             shippingMethodIcons.add(Icons.directions_car);
             if (deliveryMethod == 'store-delivery') {
@@ -1107,7 +1107,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
             }
             i++;
           }
-          if (cartInfo.businessInfo.deliveryCanadaPost) {
+          if (cartInfo!.businessInfo!.deliveryCanadaPost) {
             shippingMethodLabels.add(S.of(context).canada_post);
             shippingMethodIcons.add(Icons.local_shipping);
             if (deliveryMethod == 'canada-post') {
@@ -1115,7 +1115,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
             }
             i++;
           }
-          if (cartInfo.businessInfo.deliveryPickup) {
+          if (cartInfo!.businessInfo!.deliveryPickup) {
             shippingMethodLabels.add(S.of(context).pickup);
             shippingMethodIcons.add(Icons.store);
             if (deliveryMethod == 'pickup') {
@@ -1335,14 +1335,14 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                 Expanded(
                   child: SizedBox.expand(
                     child: ListView.builder(
-                      itemCount: bookingDateTimeList[bookingDateIndex].bookTimes.length,
+                      itemCount: bookingDateTimeList[bookingDateIndex].bookTimes!.length,
                       itemBuilder: (BuildContext context, int position) {
                         BookingDateTime bookingDateTime = bookingDateTimeList[bookingDateIndex];
                         return GestureDetector(
                           child: Container(
                             padding: EdgeInsets.only(left: 12.0, right: 12.0, top: 12.0, bottom: 12.0),
                             child: Text(
-                              bookingDateTime.bookTimes[position].viewTime,
+                              bookingDateTime.bookTimes![position].viewTime,
                             ),
                             decoration: BoxDecoration(
                               border: Border(
@@ -1467,16 +1467,16 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
             itemBuilder: (BuildContext context, int position) {
               PaymentPlatform paymentPlatform = paymentPlatforms[position];
               if (paymentPlatform.code == Constants.PAYMENT_METHOD_CODE_SQUARE &&
-                  (paymentPlatform.squareAppId == null || paymentPlatform.squareAppId.isEmpty) &&
-                  (paymentPlatform.squareAccessToken == null || paymentPlatform.squareAccessToken.isEmpty) &&
-                  (paymentPlatform.squareLocationId == null || paymentPlatform.squareLocationId.isEmpty)
+                  (paymentPlatform.squareAppId == null || paymentPlatform.squareAppId!.isEmpty) &&
+                  (paymentPlatform.squareAccessToken == null || paymentPlatform.squareAccessToken!.isEmpty) &&
+                  (paymentPlatform.squareLocationId == null || paymentPlatform.squareLocationId!.isEmpty)
               ) {
                 return SizedBox.shrink();
               }
               if (paymentPlatform.code == Constants.PAYMENT_METHOD_CODE_CHASE &&
-                  (paymentPlatform.xLogin == null || paymentPlatform.xLogin.isEmpty) &&
-                  (paymentPlatform.transactionKey == null || paymentPlatform.transactionKey.isEmpty) &&
-                  (paymentPlatform.responseKey == null || paymentPlatform.responseKey.isEmpty)
+                  (paymentPlatform.xLogin == null || paymentPlatform.xLogin!.isEmpty) &&
+                  (paymentPlatform.transactionKey == null || paymentPlatform.transactionKey!.isEmpty) &&
+                  (paymentPlatform.responseKey == null || paymentPlatform.responseKey!.isEmpty)
               ) {
                 return SizedBox.shrink();
               }
@@ -1566,7 +1566,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
 
   String getSelectedCouponName() {
     if (selectedCoupon == null) {
-      if (coupons.length > 0) {
+      if (coupons!.length > 0) {
         return S
             .of(context)
             .please_select;
@@ -1578,10 +1578,10 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
     } else if (selectedCoupon == 0) {
       return S.of(context).dont_use;
     } else {
-      for (var i = 0; i < coupons.length; i++) {
-        if (selectedCoupon == coupons[i].id) {
-          if (coupons[i].isPercentage) {
-            return S.of(context).percentage_discount_token2(couponDiscountAmount.toStringAsFixed(2), coupons[i].valueAmount);
+      for (var i = 0; i < coupons!.length; i++) {
+        if (selectedCoupon == coupons![i].id) {
+          if (coupons![i].isPercentage) {
+            return S.of(context).percentage_discount_token2(couponDiscountAmount.toStringAsFixed(2), coupons![i].valueAmount);
           } else {
             return S.of(context).discount_amount_token(couponDiscountAmount.toStringAsFixed(2));
           }
@@ -1700,13 +1700,13 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
     } else {
       widget.children.add(Expanded(
         child: ListView.builder(
-          itemCount: coupons.length + 1,
+          itemCount: coupons!.length + 1,
           itemBuilder: (BuildContext context, int position) {
             if (position == 0) {
               return GestureDetector(
                 child: Container(
                   decoration: selectedCoupon == 0 ? BoxDecoration(
-                    color: subtotal > cartInfo.businessInfo.minPrice ? Colors
+                    color: subtotal > cartInfo!.businessInfo!.minPrice ? Colors
                         .transparent : Colors.black38,
                     border: Border(
                       top: BorderSide(
@@ -1727,7 +1727,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                       ),
                     ),
                   ) : BoxDecoration(
-                    color: subtotal > cartInfo.businessInfo.minPrice ? Colors
+                    color: subtotal > cartInfo!.businessInfo!.minPrice ? Colors
                         .transparent : Colors.black38,
                   ),
                   child: Row(
@@ -1764,11 +1764,11 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                 },
               );
             } else {
-              Coupon coupon = coupons[position - 1];
+              Coupon coupon = coupons![position - 1];
               return GestureDetector(
                 child: Container(
                   decoration: selectedCoupon == coupon.id ? BoxDecoration(
-                    color: subtotal > cartInfo.businessInfo.minPrice ? Colors
+                    color: subtotal > cartInfo!.businessInfo!.minPrice ? Colors
                         .transparent : Colors.black38,
                     border: Border(
                       top: BorderSide(
@@ -1882,7 +1882,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                               ),
                               Container(
                                 child: Text(
-                                  coupon.minAmount > 0 ?
+                                  coupon.minAmount! > 0 ?
                                   S.of(context).min_order_amount_token(
                                       coupon.minAmount) :
                                   S.of(context)
@@ -1942,7 +1942,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
       crossAxisAlignment: CrossAxisAlignment.start,
       children: [],
     );
-    if (cartInfo.businessInfo.quickInputs.length > 0) {
+    if (cartInfo!.businessInfo!.quickInputs!.length > 0) {
       Wrap w = Wrap(
         children: [],
       );
@@ -1956,8 +1956,8 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
           ),
         ),
       ));
-      for (int i = 0; i < cartInfo.businessInfo.quickInputs.length; i++) {
-        String qi = cartInfo.businessInfo.quickInputs[i].value;
+      for (int i = 0; i < cartInfo!.businessInfo!.quickInputs!.length; i++) {
+        String qi = cartInfo!.businessInfo!.quickInputs![i].value;
         w.children.add(TextButton(
           child: Text(
             qi,
@@ -2137,7 +2137,7 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
                     child: Container(
                       alignment: Alignment.centerRight,
                       child: Text(
-                        '${shippingRate.price.toStringAsFixed(2)}',
+                        '${shippingRate.price!.toStringAsFixed(2)}',
                         style: TextStyle(
                           fontSize: 16.0,
                           color: Colors.black38,
@@ -2221,14 +2221,14 @@ class DesktopCheckoutState extends State<DesktopCheckout> with SingleTickerProvi
       },
         businessId: widget.businessId,
         body: {
-          'cart_id': cartInfo.id,
+          'cart_id': cartInfo!.id,
           'remark': orderRemark,
           'booked_at': bookingTimeList.length > 0
               ? bookingTimeList[bookingTimeIndex].unixTime
               : (
               (bookingTimeList.length == 0 && bookingDateTimeList.length == 0) ?
               0 :
-              bookingDateTimeList[bookingDateIndex].bookTimes[bookingTimeIndex]
+              bookingDateTimeList[bookingDateIndex].bookTimes![bookingTimeIndex]
                   .unixTime
           ),
           'delivery': deliveryMethod,

lib/widgets/desktop/desktop_contact_us.dart

@@ -35,7 +35,7 @@ class DesktopContactUsState extends State<DesktopContactUs> {
   String mapUrl = 'https://goo.gl/maps/M365MF5AW35n9ij67';
 
   Completer<GoogleMapController> _controller = Completer();
-  LatLng _lastMapPosition;
+  late LatLng _lastMapPosition;
   final Set<Marker> _markers = {};
   final Set<Polyline> _polyLine = {};
 
@@ -253,16 +253,16 @@ class DesktopContactUsState extends State<DesktopContactUs> {
         Container(
           padding: EdgeInsets.only(left: 16, right: 16, top: 4, bottom: 4),
           child: Text(
-            '${widget.business.address.addressLine1}',
+            '${widget.business.address!.addressLine1}',
           ),
         )
     );
-    if (widget.business.address.addressLine2 != null && widget.business.address.addressLine2.isNotEmpty) {
+    if (widget.business.address!.addressLine2 != null && widget.business.address!.addressLine2!.isNotEmpty) {
       col.children.add(
           Container(
             padding: EdgeInsets.only(left: 16, right: 16, top: 4, bottom: 4),
             child: Text(
-              '${widget.business.address.addressLine2}',
+              '${widget.business.address!.addressLine2}',
             ),
           )
       );
@@ -271,7 +271,7 @@ class DesktopContactUsState extends State<DesktopContactUs> {
         Container(
           padding: EdgeInsets.only(left: 16, right: 16, top: 4, bottom: 4),
           child: Text(
-            '${widget.business.address.city}, ${widget.business.address.state}',
+            '${widget.business.address!.city}, ${widget.business.address!.state}',
           ),
         )
     );
@@ -279,7 +279,7 @@ class DesktopContactUsState extends State<DesktopContactUs> {
         Container(
           padding: EdgeInsets.only(left: 16, right: 16, top: 4, bottom: 4),
           child: Text(
-            '${widget.business.address.country}, ${widget.business.address.zip}',
+            '${widget.business.address!.country}, ${widget.business.address!.zip}',
           ),
         )
     );
@@ -287,8 +287,8 @@ class DesktopContactUsState extends State<DesktopContactUs> {
       _markers.clear();
       _markers.add(Marker(
         markerId: MarkerId('shop_position'),
-        position: LatLng(double.parse(widget.business.address.lat),
-            double.parse(widget.business.address.lng)),
+        position: LatLng(double.parse(widget.business.address!.lat),
+            double.parse(widget.business.address!.lng)),
         infoWindow: InfoWindow(
           title: S
               .of(context)
@@ -304,8 +304,8 @@ class DesktopContactUsState extends State<DesktopContactUs> {
             onMapCreated: _onMapCreated,
             initialCameraPosition: CameraPosition(
               target: LatLng(
-                  double.parse(widget.business.address.lat),
-                  double.parse(widget.business.address.lng)),
+                  double.parse(widget.business.address!.lat),
+                  double.parse(widget.business.address!.lng)),
               zoom: 14.0,
             ),
             onCameraMove: _onCameraMove,

lib/widgets/desktop/desktop_coupons.dart

@@ -27,7 +27,7 @@ class DesktopCoupons extends StatefulWidget {
 }
 
 class DesktopCouponsState extends State<DesktopCoupons> {
-  List<Coupon> coupons;
+  late List<Coupon> coupons;
 
   double sideSpace = 0;
   double mainSpace = 1200;
@@ -120,7 +120,7 @@ class DesktopCouponsState extends State<DesktopCoupons> {
                 Container(
                   padding: EdgeInsets.only(right: 5.0),
                   child: coupon.store != null ?
-                  Util.showImage('${coupon.store.picUrl}',
+                  Util.showImage('${coupon.store!.picUrl}',
                     fit: BoxFit.fill,
                     width: 40.0,
                   ) :
@@ -137,7 +137,7 @@ class DesktopCouponsState extends State<DesktopCoupons> {
                     crossAxisAlignment: CrossAxisAlignment.start,
                     children: <Widget>[
                       Text(
-                        coupon.store != null ? coupon.store.name : S.of(context).general_coupon,
+                        coupon.store != null ? coupon.store!.name : S.of(context).general_coupon,
                         style: TextStyle(
                           fontSize: 20.0,
                           fontWeight: FontWeight.bold,
@@ -221,7 +221,7 @@ class DesktopCouponsState extends State<DesktopCoupons> {
         ),
         Container(
           child: Text(
-            coupon.minAmount > 0 ?
+            coupon.minAmount! > 0 ?
             S.of(context).available_for_order_over_token(coupon.minAmount) :
             S.of(context).no_restriction,
             style: TextStyle(
@@ -259,7 +259,7 @@ class DesktopCouponsState extends State<DesktopCoupons> {
         children: <Widget>[
           Container(
             child: Text(
-              coupon.expirationDate == null || coupon.expirationDate.length == 0 ?
+              coupon.expirationDate == null || coupon.expirationDate!.length == 0 ?
                   S.of(context).no_expiration :
                   S.of(context).expiration_date_token(coupon.expirationDate),
               style: TextStyle(
@@ -284,7 +284,7 @@ class DesktopCouponsState extends State<DesktopCoupons> {
               ),
               onPressed: () {
                 if (coupon.store != null) {
-                  Routes.router.navigateTo(context, '/shop/${coupon.store.id}/na/na/na');
+                  Routes.router.navigateTo(context, '/shop/${coupon.store!.id}/na/na/na');
                 } else {
                   Routes.router.navigateTo(context, '/businesses');
                 }

lib/widgets/desktop/desktop_edit_address.dart

@@ -45,12 +45,12 @@ class DesktopEditAddressState extends State<DesktopEditAddress> {
   final emailController = TextEditingController();
   final faxController = TextEditingController();
 
-  String country;
-  Gender _selectedGender;
+  late String country;
+  late Gender _selectedGender;
 
-  String _selectedProvince;
+  late String _selectedProvince;
 
-  bool showLoading;
+  late bool showLoading;
 
   double sideSpace = 0;
   double mainSpace = 1200;
@@ -362,7 +362,7 @@ class DesktopEditAddressState extends State<DesktopEditAddress> {
                     .email,
               ),
               validator: (String? value) {
-                if (value.isNotEmpty && !EmailValidator.validate(value)) {
+                if (value!.isNotEmpty && !EmailValidator.validate(value)) {
                   return S
                       .of(context)
                       .email_is_not_valid;

lib/widgets/desktop/desktop_forgot_password.dart

@@ -29,9 +29,9 @@ class DesktopForgotPasswordState extends State<DesktopForgotPassword> {
   bool usernameEnable = true;
   final codeController = TextEditingController();
 
-  bool enableGetCode;
-  String getCodeText;
-  bool canRegister;
+  late bool enableGetCode;
+  late String getCodeText;
+  late bool canRegister;
 
   var countDownListener;
 
@@ -84,7 +84,7 @@ class DesktopForgotPasswordState extends State<DesktopForgotPassword> {
                     ),
                     autofocus: true,
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         return S.of(context).mobile_or_email_is_required;
                       }
                       return null;
@@ -167,7 +167,7 @@ class DesktopForgotPasswordState extends State<DesktopForgotPassword> {
                         fontSize: 18.0
                     ),
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         return S.of(context).verification_code_is_required;
                       }
                       return null;

lib/widgets/desktop/desktop_login.dart

@@ -26,9 +26,9 @@ class DesktopLoginState extends State<DesktopLogin> {
 
   final usernameController = TextEditingController();
   final passwordController = TextEditingController();
-  bool passwordVisible;
+  late bool passwordVisible;
 
-  bool onSubmitting;
+  late bool onSubmitting;
 
   double sideSpace = 0;
   double mainSpace = 1200;
@@ -150,7 +150,7 @@ class DesktopLoginState extends State<DesktopLogin> {
                                 style: TextStyle(fontSize: 18.0),
                                 autofocus: true,
                                 validator: (String? value) {
-                                  if (value.trim().isEmpty) {
+                                  if (value!.trim().isEmpty) {
                                     return S.of(context).this_field_is_required;
                                   }
                                   return null;
@@ -194,7 +194,7 @@ class DesktopLoginState extends State<DesktopLogin> {
                                 style: TextStyle(fontSize: 18.0),
                                 obscureText: passwordVisible,
                                 validator: (String? value) {
-                                  if (value.trim().isEmpty) {
+                                  if (value!.trim().isEmpty) {
                                     return S.of(context).password_is_required;
                                   }
                                   return null;

lib/widgets/desktop/desktop_me.dart

@@ -16,9 +16,9 @@ import '../../utils/util_web.dart'
     if (dart.library.io) '../../utils/util_io.dart';
 import '../../utils/utils.dart';
 
-MediaQueryData mediaQuery;
-double statusBarHeight;
-double screenHeight;
+late MediaQueryData mediaQuery;
+late double statusBarHeight;
+late double screenHeight;
 
 class DesktopMe extends StatefulWidget {
   final Key? key;
@@ -32,11 +32,11 @@ class DesktopMe extends StatefulWidget {
 }
 
 class DesktopMeState extends State<DesktopMe> {
-  int userId;
-  String accessToken;
+  late int userId;
+  late String accessToken;
 
-  bool isLoading;
-  User _user;
+  late bool isLoading;
+  late User _user;
 
   double sideSpace = 0;
   double mainSpace = 1200;
@@ -81,7 +81,7 @@ class DesktopMeState extends State<DesktopMe> {
           children: <Widget>[
             Container(
               margin: EdgeInsets.only(right: 5.0),
-              child: _user != null && _user.avatarUrl.isNotEmpty
+              child: _user != null && _user.avatarUrl!.isNotEmpty
                   ? Util.showImage(
                       'https:${_user.avatarUrl}',
                       width: 60,
@@ -182,7 +182,7 @@ class DesktopMeState extends State<DesktopMe> {
                                 Container(
                                   child: Text(
                                     _user != null
-                                        ? '${_user.wallet.toStringAsFixed(2)}'
+                                        ? '${_user.wallet!.toStringAsFixed(2)}'
                                         : '0.00',
                                     style: TextStyle(
                                       fontSize: 24.0,

lib/widgets/desktop/desktop_my_addresses.dart

@@ -30,7 +30,7 @@ class DesktopMyAddresses extends StatefulWidget {
 }
 
 class DesktopMyAddressesState extends State<DesktopMyAddresses> {
-  List<Address> addresses;
+  late List<Address> addresses;
 
   double sideSpace = 0;
   double mainSpace = 1200;

lib/widgets/desktop/desktop_my_support.dart

@@ -30,7 +30,7 @@ class DesktopMySupport extends StatefulWidget {
 }
 
 class DesktopMySupportState extends State<DesktopMySupport> {
-  List<Ticket> tickets;
+  late List<Ticket> tickets;
 
   double division = 3;
 
@@ -218,7 +218,7 @@ class DesktopMySupportState extends State<DesktopMySupport> {
                 children: <Widget>[
                   Container(
                     child: Text(
-                      ticket.issue.msg,
+                      ticket.issue!.msg,
                       style: TextStyle(
                         fontSize: 19.0,
                       ),
@@ -248,7 +248,7 @@ class DesktopMySupportState extends State<DesktopMySupport> {
                         SizedBox.shrink(),
                         Expanded(
                           child: Text(
-                            S.of(context).followups_token(ticket.followUps.length),
+                            S.of(context).followups_token(ticket.followUps!.length),
                             style: TextStyle(
                               fontSize: 15.0,
                               color: Colors.black87,

lib/widgets/desktop/desktop_new_address.dart

@@ -39,9 +39,9 @@ class DesktopNewAddressState extends State<DesktopNewAddress> {
   final faxController = TextEditingController();
 
   String country = 'CA';
-  Gender _selectedGender;
+  late Gender _selectedGender;
 
-  String _selectedProvince;
+  late String _selectedProvince;
 
   double sideSpace = 0;
   double mainSpace = 1200;
@@ -98,7 +98,7 @@ class DesktopNewAddressState extends State<DesktopNewAddress> {
                 labelText: S.of(context).contact_name,
               ),
               validator: (String? value) {
-                if (value.trim().isEmpty) {
+                if (value!.trim().isEmpty) {
                   return S.of(context).contact_name_is_required;
                 }
                 return null;
@@ -142,7 +142,7 @@ class DesktopNewAddressState extends State<DesktopNewAddress> {
                 labelText: S.of(context).mobile_phone_number,
               ),
               validator: (String? value) {
-                if (value.trim().isEmpty) {
+                if (value!.trim().isEmpty) {
                   return S.of(context).mobile_phone_number_is_required;
                 }
                 return null;
@@ -167,7 +167,7 @@ class DesktopNewAddressState extends State<DesktopNewAddress> {
                 labelText: S.of(context).street_line_1,
               ),
               validator: (String? value) {
-                if (value.trim().isEmpty) {
+                if (value!.trim().isEmpty) {
                   return S.of(context).street_line_1_is_required;
                 }
                 return null;
@@ -211,7 +211,7 @@ class DesktopNewAddressState extends State<DesktopNewAddress> {
                 labelText: S.of(context).city,
               ),
               validator: (String? value) {
-                if (value.trim().isEmpty) {
+                if (value!.trim().isEmpty) {
                   return S.of(context).city_is_required;
                 }
                 return null;
@@ -257,7 +257,7 @@ class DesktopNewAddressState extends State<DesktopNewAddress> {
                 labelText: S.of(context).postal_code,
               ),
               validator: (String? value) {
-                if (value.trim().isEmpty) {
+                if (value!.trim().isEmpty) {
                   return S.of(context).postal_code_is_required;
                 }
                 return null;
@@ -292,7 +292,7 @@ class DesktopNewAddressState extends State<DesktopNewAddress> {
                 labelText: S.of(context).email,
               ),
               validator: (String? value) {
-                if (value.isNotEmpty && !EmailValidator.validate(value)) {
+                if (value!.isNotEmpty && !EmailValidator.validate(value)) {
                   return S.of(context).email_is_not_valid;
                 }
                 return null;
@@ -383,8 +383,8 @@ class DesktopNewAddressState extends State<DesktopNewAddress> {
         cityController.text = widget.locatedAddress.city;
         postalCodeController.text = widget.locatedAddress.postalCode;
         streetLine1Controller.text = (widget.locatedAddress.streetNumber != null
-            && widget.locatedAddress.streetNumber.isNotEmpty
-            ? widget.locatedAddress.streetNumber + ' ' : '')
+            && widget.locatedAddress.streetNumber!.isNotEmpty
+            ? widget.locatedAddress.streetNumber! + ' ' : '')
             + widget.locatedAddress.streetName;
       } else {
         _selectedProvince = 'Ontario';

lib/widgets/desktop/desktop_new_comment.dart

@@ -34,13 +34,13 @@ class DesktopNewComment extends StatefulWidget {
 }
 
 class DesktopNewCommentState extends State<DesktopNewComment> {
-  Comment comment;
+  late Comment comment;
 
-  bool _showProgress;
+  late bool _showProgress;
 
-  double _progress;
+  late double _progress;
 
-  double rating;
+  late double rating;
 
   bool isSubmitting = false;
 
@@ -203,7 +203,7 @@ class DesktopNewCommentState extends State<DesktopNewComment> {
       children: <Widget>[],
     );
 
-    if (comment != null && comment.images.length > 0) {
+    if (comment != null && comment.images!.length > 0) {
       for (ProductImage image in comment.images) {
         row.children.add(
           Container(
@@ -275,7 +275,7 @@ class DesktopNewCommentState extends State<DesktopNewComment> {
           child: Icon(
             Icons.add,
             size: 60.0,
-            color: comment == null || comment.images.length < 3 ? Colors.lightBlue : Colors.black12,
+            color: comment == null || comment.images!.length < 3 ? Colors.lightBlue : Colors.black12,
           ),
           decoration: BoxDecoration(
             color: Colors.white70,
@@ -300,7 +300,7 @@ class DesktopNewCommentState extends State<DesktopNewComment> {
           ),
         ),
         onTap: () {
-          if (comment == null || comment.images.length < 3) {
+          if (comment == null || comment.images!.length < 3) {
             showDialog(
                 context: mainContext,
                 barrierDismissible: true,

lib/widgets/desktop/desktop_new_ticket.dart

@@ -155,7 +155,7 @@ class DesktopNewTicketState extends State<DesktopNewTicket> {
                               ),
                               autofocus: true,
                               validator: (String? value) {
-                                if (value.trim().isEmpty) {
+                                if (value!.trim().isEmpty) {
                                   return S.of(context).this_field_is_required;
                                 }
                                 return null;

lib/widgets/desktop/desktop_new_user.dart

@@ -28,9 +28,9 @@ class DesktopNewUserState extends State<DesktopNewUser> {
   bool usernameEnable = true;
   final codeController = TextEditingController();
 
-  bool enableGetCode;
-  String getCodeText;
-  bool canRegister;
+  late bool enableGetCode;
+  late String getCodeText;
+  late bool canRegister;
 
   var countDownListener;
 
@@ -81,7 +81,7 @@ class DesktopNewUserState extends State<DesktopNewUser> {
                     ),
                     autofocus: true,
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         return S.of(context).mobile_or_email_is_required;
                       }
                       return null;
@@ -164,7 +164,7 @@ class DesktopNewUserState extends State<DesktopNewUser> {
                         fontSize: 18.0
                     ),
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         return S.of(context).verification_code_is_required;
                       }
                       return null;

lib/widgets/desktop/desktop_order_detail.dart

@@ -39,18 +39,18 @@ class DesktopOrderDetail extends StatefulWidget {
 }
 
 class DesktopOrderDetailState extends State<DesktopOrderDetail> {
-  Order order;
+  late Order order;
 
-  LatLng _lastMapPosition;
-  LatLng customerLatLng;
-  LatLng deliveryLatLng;
-  LatLng storeLatLng;
+  late LatLng _lastMapPosition;
+  late LatLng customerLatLng;
+  late LatLng deliveryLatLng;
+  late LatLng storeLatLng;
   final Set<Marker> _markers = {};
   final Set<Polyline> _polyLine = {};
 
-  BitmapDescriptor homeIcon;
-  BitmapDescriptor deliveryIcon;
-  BitmapDescriptor shopIcon;
+  late BitmapDescriptor homeIcon;
+  late BitmapDescriptor deliveryIcon;
+  late BitmapDescriptor shopIcon;
 
   double sideSpace = 0;
   double mainSpace = 1200;
@@ -110,7 +110,7 @@ class DesktopOrderDetailState extends State<DesktopOrderDetail> {
                           width: double.infinity,
                           padding: EdgeInsets.only(top: 0.0, bottom: 16.0),
                           child: Text(
-                            order.cartInfo.businessInfo.name,
+                            order.cartInfo!.businessInfo!.name,
                             maxLines: 1,
                             overflow: TextOverflow.ellipsis,
                             style: TextStyle(
@@ -141,7 +141,7 @@ class DesktopOrderDetailState extends State<DesktopOrderDetail> {
                           Icons.phone,
                         ),
                         onTap: () {
-                          Utils.launchURL('tel:${order.businessInfo.phone}');
+                          Utils.launchURL('tel:${order.businessInfo!.phone}');
                         },
                       ),
                     ),
@@ -156,7 +156,7 @@ class DesktopOrderDetailState extends State<DesktopOrderDetail> {
                   child: GoogleMap(
                     onMapCreated: _onMapCreated,
                     initialCameraPosition: CameraPosition(
-                      target: new LatLng(double.parse(order.shippingAddress.lat), double.parse(order.shippingAddress.lng)),
+                      target: new LatLng(double.parse(order.shippingAddress!.lat), double.parse(order.shippingAddress!.lng)),
                       zoom: 11.0,
                     ),
                     onCameraMove: _onCameraMove,
@@ -167,14 +167,14 @@ class DesktopOrderDetailState extends State<DesktopOrderDetail> {
                     ].toSet(),
                   ),
                 ));
-                if (order.deliveryDistance != null && order.deliveryDistance.distance != null) {
+                if (order.deliveryDistance != null && order.deliveryDistance!.distance != null) {
                   col.children.add(Container(
                     padding: EdgeInsets.only(top: 6.0, bottom: 6.0),
                     margin: EdgeInsets.only(bottom: 6.0),
                     child: Text(
                       S.of(context).delivery_distance_token(
-                          order.deliveryDistance.distance.text,
-                          order.deliveryDistance.duration.text
+                          order.deliveryDistance!.distance!.text,
+                          order.deliveryDistance!.duration!.text
                       ),
                     ),
                     decoration: BoxDecoration(
@@ -190,7 +190,7 @@ class DesktopOrderDetailState extends State<DesktopOrderDetail> {
               }
             }
 
-            for (CartLineItem lineItem in order.cartInfo.productList) {
+            for (CartLineItem lineItem in order.cartInfo!.productList) {
 
               col.children.add(Container(
                 padding: EdgeInsets.only(top: 16.0, bottom: 0.0),
@@ -198,7 +198,7 @@ class DesktopOrderDetailState extends State<DesktopOrderDetail> {
                   mainAxisAlignment: MainAxisAlignment.start,
                   crossAxisAlignment: CrossAxisAlignment.start,
                   children: <Widget>[
-                    Util.showImage('${lineItem.product.imagePath}',
+                    Util.showImage('${lineItem.product!.imagePath}',
                       width: 40.0,
                       height: 40.0,
                       fit: BoxFit.fill,
@@ -236,7 +236,7 @@ class DesktopOrderDetailState extends State<DesktopOrderDetail> {
                       width: 30.0,
                       alignment: Alignment.centerRight,
                       child: Text(
-                        'x${lineItem.quantity.round()}',
+                        'x${lineItem.quantity!.round()}',
                         style: TextStyle(
                           fontSize: 14.0,
                         ),
@@ -298,8 +298,8 @@ class DesktopOrderDetailState extends State<DesktopOrderDetail> {
                 ],
               ),
             );
-            for (var i = 0; i < order.cartInfo.extraFeeList.length; i++) {
-              ExtraFee extraFee = order.cartInfo.extraFeeList[i];
+            for (var i = 0; i < order.cartInfo!.extraFeeList!.length; i++) {
+              ExtraFee extraFee = order.cartInfo!.extraFeeList![i];
               col.children.add(
                 Row(
                   mainAxisAlignment: MainAxisAlignment.start,
@@ -323,7 +323,7 @@ class DesktopOrderDetailState extends State<DesktopOrderDetail> {
                       width: 100.0,
                       alignment: Alignment.centerRight,
                       child: Text(
-                        '${extraFee.price.toStringAsFixed(2)}',
+                        '${extraFee.price!.toStringAsFixed(2)}',
                         style: TextStyle(
                           fontSize: 15.0,
                         ),
@@ -356,7 +356,7 @@ class DesktopOrderDetailState extends State<DesktopOrderDetail> {
                     width: 100.0,
                     alignment: Alignment.centerRight,
                     child: Text(
-                      '${order.totalPrice.toStringAsFixed(2)}',
+                      '${order.totalPrice!.toStringAsFixed(2)}',
                       style: TextStyle(
                         fontSize: 18.0,
                         fontWeight: FontWeight.bold,
@@ -466,7 +466,7 @@ class DesktopOrderDetailState extends State<DesktopOrderDetail> {
                         margin: EdgeInsets.only(top: 10.0, bottom: 10.0),
                         alignment: Alignment.centerRight,
                         child: Text(
-                          '${order.cartInfo.businessInfo.fullAddress}',
+                          '${order.cartInfo!.businessInfo!.fullAddress}',
                           style: TextStyle(
                             color: Colors.black38,
                           ),
@@ -893,19 +893,19 @@ class DesktopOrderDetailState extends State<DesktopOrderDetail> {
                   crossAxisAlignment: CrossAxisAlignment.start,
                   children: <Widget>[
                     Container(
-                      child: fulfillment.shippingMethod.isNotEmpty && fulfillment.trackingNumber != null && fulfillment.trackingNumber.isNotEmpty ?
+                      child: fulfillment.shippingMethod!.isNotEmpty && fulfillment.trackingNumber != null && fulfillment.trackingNumber!.isNotEmpty ?
                       Text(
                         '${fulfillment.shippingMethod} ${fulfillment.trackingNumber}',
                         overflow: TextOverflow.ellipsis,
                         maxLines: 1,
-                      ) : (fulfillment.shippingMethod.isNotEmpty ? Text(
+                      ) : (fulfillment.shippingMethod!.isNotEmpty ? Text(
                         '${fulfillment.shippingMethod}',
                         overflow: TextOverflow.ellipsis,
                         maxLines: 1,
                       ) : SizedBox.shrink()),
                     ),
                     Container(
-                      child: fulfillment.note != null && fulfillment.note.isNotEmpty ?
+                      child: fulfillment.note != null && fulfillment.note!.isNotEmpty ?
                       Text(
                         '${fulfillment.note}',
                         style: TextStyle(
@@ -1092,12 +1092,12 @@ class DesktopOrderDetailState extends State<DesktopOrderDetail> {
 
           if (!kIsWeb) {
             if (order.shippingMethod == 'store-delivery' && order.status != Constants.STATUS_COMPLETE && order.status != Constants.STATUS_CANCELLED) {
-              storeLatLng = LatLng(double.parse(order.businessInfo.address.lat),
-                  double.parse(order.businessInfo.address.lng));
-              customerLatLng = LatLng(double.parse(order.shippingAddress.lat),
-                  double.parse(order.shippingAddress.lng));
+              storeLatLng = LatLng(double.parse(order.businessInfo!.address!.lat),
+                  double.parse(order.businessInfo!.address!.lng));
+              customerLatLng = LatLng(double.parse(order.shippingAddress!.lat),
+                  double.parse(order.shippingAddress!.lng));
               deliveryLatLng =
-                  LatLng(order.shipperPosition.lat, order.shipperPosition.lng);
+                  LatLng(order.shipperPosition!.lat, order.shipperPosition!.lng);
 
               _polyLine.clear();
               _polyLine.add(
@@ -1110,7 +1110,7 @@ class DesktopOrderDetailState extends State<DesktopOrderDetail> {
                       ],
                       width: 3,
                       points: [
-                        order.shipperPosition.lat != 0.0 ? deliveryLatLng : storeLatLng,
+                        order.shipperPosition!.lat != 0.0 ? deliveryLatLng : storeLatLng,
                         customerLatLng,
                       ]
                   )
@@ -1135,12 +1135,12 @@ class DesktopOrderDetailState extends State<DesktopOrderDetail> {
                   title: S
                       .of(context)
                       .customer,
-                  snippet: order.shippingAddress.addressLine1,
+                  snippet: order.shippingAddress!.addressLine1,
                 ),
                 icon: homeIcon,
               ));
-              if (order.shipperPosition.lat != 0.0 &&
-                  order.shipperPosition.lng != 0.0) {
+              if (order.shipperPosition!.lat != 0.0 &&
+                  order.shipperPosition!.lng != 0.0) {
                 _markers.add(Marker(
                   markerId: MarkerId('shipper_position'),
                   position: deliveryLatLng,

lib/widgets/desktop/desktop_orders.dart

@@ -35,7 +35,7 @@ class DesktopOrders extends StatefulWidget {
 class DesktopOrdersState extends State<DesktopOrders> with SingleTickerProviderStateMixin {
   GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();
 
-  List<Order> orders;
+  late List<Order> orders;
 
   bool _isLoading = false;
 
@@ -181,7 +181,7 @@ class DesktopOrdersState extends State<DesktopOrders> with SingleTickerProviderS
         row.children.add(Expanded(
           child: Container(
             child: Text(
-              order.cartInfo.productList[0].name,
+              order.cartInfo!.productList![0].name,
               style: TextStyle(
                 fontSize: 14.0,
               ),
@@ -190,7 +190,7 @@ class DesktopOrdersState extends State<DesktopOrders> with SingleTickerProviderS
             ),
           ),
         ));
-        if (order.cartInfo.productList.length > 1) {
+        if (order.cartInfo!.productList!.length > 1) {
           row.children.add(Container(
             child: Text(
               S.of(context).and_more_item_token(Utils.getProductLineInOrder(order.cartInfo)),
@@ -205,7 +205,7 @@ class DesktopOrdersState extends State<DesktopOrders> with SingleTickerProviderS
           width: 80.0,
           alignment: Alignment.centerRight,
           child: Text(
-            '\$${order.totalPrice.toStringAsFixed(2)}',
+            '\$${order.totalPrice!.toStringAsFixed(2)}',
             style: TextStyle(
               fontSize: 16.0,
               fontWeight: FontWeight.bold,
@@ -320,7 +320,7 @@ class DesktopOrdersState extends State<DesktopOrders> with SingleTickerProviderS
                 mainAxisAlignment: MainAxisAlignment.start,
                 children: <Widget>[
                   Container(
-                    child: Util.showImage('${order.cartInfo.businessInfo.picUrl}',
+                    child: Util.showImage('${order.cartInfo!.businessInfo!.picUrl}',
                       width: 32.0,
                       height: 32.0,
                       fit: BoxFit.fill,
@@ -336,7 +336,7 @@ class DesktopOrdersState extends State<DesktopOrders> with SingleTickerProviderS
                           children: <Widget>[
                             Container(
                               child: Text(
-                                '${order.cartInfo.businessInfo.name}',
+                                '${order.cartInfo!.businessInfo!.name}',
                                 style: TextStyle(
                                   fontSize: 20.0,
                                 ),

lib/widgets/desktop/desktop_pay_now.dart

@@ -32,9 +32,9 @@ class DesktopPayNow extends StatefulWidget {
 }
 
 class DesktopPayNowState extends State<DesktopPayNow> {
-  Order order;
-  List<PaymentPlatform> paymentPlatforms;
-  User _user;
+  late Order order;
+  late List<PaymentPlatform> paymentPlatforms;
+  late User _user;
 
   double sideSpace = 0;
   double mainSpace = 1200;
@@ -86,7 +86,7 @@ class DesktopPayNowState extends State<DesktopPayNow> {
                       ),
                     ),
                     Text(
-                      '\$${order.totalPrice.toStringAsFixed(2)}',
+                      '\$${order.totalPrice!.toStringAsFixed(2)}',
                       style: TextStyle(
                         fontSize: 24.0,
                         fontWeight: FontWeight.bold,
@@ -103,7 +103,7 @@ class DesktopPayNowState extends State<DesktopPayNow> {
                     )
                 ),
               ),
-              store.state.deviceId != null && store.state.deviceId.isNotEmpty || store.state.tableNumber != null && store.state.tableNumber.isNotEmpty ?
+              store.state.deviceId != null && store.state.deviceId!.isNotEmpty || store.state.tableNumber != null && store.state.tableNumber!.isNotEmpty ?
               GestureDetector(
                 child: Container(
                   padding: EdgeInsets.only(top: 20.0, bottom: 20.0, left: 16.0, right: 16.0),

lib/widgets/desktop/desktop_product_detail_page.dart

@@ -42,13 +42,13 @@ class DesktopProductDetailPage extends StatefulWidget {
 class DesktopProductDetailPageState extends State<DesktopProductDetailPage>
     with SingleTickerProviderStateMixin {
 
-  TabController _tabController;
+  late TabController _tabController;
 
   final double _tabBarHeight = 50;
 
-  ProductDetail productDetail;
+  late ProductDetail productDetail;
 
-  bool refresh;
+  late bool refresh;
 
   double sideSpace = 0;
   double mainSpace = 1200;
@@ -207,7 +207,7 @@ class DesktopProductDetailPageState extends State<DesktopProductDetailPage>
                                             mainAxisAlignment: MainAxisAlignment.start,
                                             crossAxisAlignment: CrossAxisAlignment.start,
                                             children: <Widget>[
-                                              (productDetail.subproducts.length > 0) ?
+                                              (productDetail.subproducts!.length > 0) ?
                                                   subProducts(productDetail.subproducts) :
                                                   SizedBox.shrink(),
                                               Container(
@@ -222,7 +222,7 @@ class DesktopProductDetailPageState extends State<DesktopProductDetailPage>
                                               Container(
                                                 padding: EdgeInsets.only(left: 10.0, right: 10.0),
                                                 child: (productDetail.description2 != null &&
-                                                    !productDetail.description2.isEmpty)
+                                                    !productDetail.description2!.isEmpty)
                                                     ? Text(
                                                   '${productDetail.description2}',
                                                   style: TextStyle(
@@ -299,7 +299,7 @@ class DesktopProductDetailPageState extends State<DesktopProductDetailPage>
   }
 
   Widget getImage(double width) {
-    if (productDetail.images.length <= 0) {
+    if (productDetail.images!.length <= 0) {
       return Util.showImage(
         productDetail.image,
         width: width,
@@ -346,7 +346,7 @@ class DesktopProductDetailPageState extends State<DesktopProductDetailPage>
       Container(
         padding: EdgeInsets.symmetric(horizontal: 12.0, vertical: 5.0),
         child: Util.showImage(
-          'https:${subproduct.product.image}',
+          'https:${subproduct.product!.image}',
           width: 48,
           height: 48,
           fit: BoxFit.contain,
@@ -366,7 +366,7 @@ class DesktopProductDetailPageState extends State<DesktopProductDetailPage>
                   child: Container(
                     padding: EdgeInsets.only(left: 12, top: 5),
                     child: Text(
-                      subproduct.product.name,
+                      subproduct.product!.name,
                       style: TextStyle(
                         fontSize: 15.0,
                       ),
@@ -377,7 +377,7 @@ class DesktopProductDetailPageState extends State<DesktopProductDetailPage>
                   width: 80,
                   padding: EdgeInsets.only(left: 12, top: 5, right: 12),
                   child: Text(
-                    '${subproduct.product.price.toStringAsFixed(2)}',
+                    '${subproduct.product!.price!.toStringAsFixed(2)}',
                     style: TextStyle(
                       fontSize: 13,
                       decoration: TextDecoration.lineThrough,
@@ -389,7 +389,7 @@ class DesktopProductDetailPageState extends State<DesktopProductDetailPage>
                   width: 60,
                   padding: EdgeInsets.only(left: 12, top: 5, right: 12),
                   child: Text(
-                    'x${subproduct.quantity.toStringAsFixed(0)}',
+                    'x${subproduct.quantity!.toStringAsFixed(0)}',
                     style: TextStyle(
                       fontSize: 13,
                     ),
@@ -401,7 +401,7 @@ class DesktopProductDetailPageState extends State<DesktopProductDetailPage>
             Container(
               padding: EdgeInsets.only(left: 12, top: 12, right: 12),
               child: Text(
-                '${subproduct.product.description}',
+                '${subproduct.product!.description}',
                 style: TextStyle(
                   fontSize: 12,
                   color: Colors.black45,
@@ -453,9 +453,9 @@ class DesktopProductDetailPageState extends State<DesktopProductDetailPage>
     var pages = <Widget>[];
     List<String> images = [];
     images.add(productDetail.image);
-    for (var i = 0; i < productDetail.images.length; i++) {
+    for (var i = 0; i < productDetail.images!.length; i++) {
       // print('>>https:' + productDetail.images[i].image);
-      images.add(productDetail.images[i].image);
+      images.add(productDetail.images![i].image);
     }
 
     for (var i = 0; i < images.length; i++) {

lib/widgets/desktop/desktop_product_item.dart

@@ -109,7 +109,7 @@ class DesktopProductItemState extends State<DesktopProductItem> {
                       new Container(
                         child: widget.business.showMonthlySold ?
                         Text(
-                          S.of(context).sold_per_month_token(widget.product.monthSales.toStringAsFixed(0)),
+                          S.of(context).sold_per_month_token(widget.product.monthSales!.toStringAsFixed(0)),
                           style: new TextStyle(
                               fontSize: 9.0
                           ),
@@ -193,7 +193,7 @@ class DesktopProductItemState extends State<DesktopProductItem> {
                       new Container(
                         child: widget.business.showMonthlySold ?
                         Text(
-                          S.of(context).sold_per_month_token(widget.product.monthSales.toStringAsFixed(0)),
+                          S.of(context).sold_per_month_token(widget.product.monthSales!.toStringAsFixed(0)),
                           style: new TextStyle(
                               fontSize: 9.0
                           ),

lib/widgets/desktop/desktop_renew_license.dart

@@ -134,7 +134,7 @@ class DesktopRenewLicenseState extends State<DesktopRenewLicense> {
                   ),
                   autofocus: true,
                   validator: (String? value) {
-                    if (value.trim().isEmpty) {
+                    if (value!.trim().isEmpty) {
                       return S.of(context).please_enter_group_number;
                     }
                     return null;

lib/widgets/desktop/desktop_reset_password.dart

@@ -26,10 +26,10 @@ class DesktopResetPasswordState extends State<DesktopResetPassword> {
   final passwordController = TextEditingController();
   final passwordAgainController = TextEditingController();
 
-  bool passwordVisible;
-  bool passwordAgainVisible;
+  late bool passwordVisible;
+  late bool passwordAgainVisible;
 
-  bool canReset;
+  late bool canReset;
 
   double sideSpace = 0;
   double mainSpace = 1200;
@@ -93,7 +93,7 @@ class DesktopResetPasswordState extends State<DesktopResetPassword> {
                     fontSize: 18.0
                 ),
                 validator: (String? value) {
-                  if (value.trim().isEmpty) {
+                  if (value!.trim().isEmpty) {
                     return S.of(context).password_is_required;
                   }
                   return null;
@@ -147,10 +147,10 @@ class DesktopResetPasswordState extends State<DesktopResetPassword> {
                     fontSize: 18.0
                 ),
                 validator: (String? value) {
-                  if (value.trim().isEmpty) {
+                  if (value!.trim().isEmpty) {
                     return S.of(context).password_is_required;
                   }
-                  if (value.trim() != passwordController.text.trim()) {
+                  if (value!.trim() != passwordController.text.trim()) {
                     return S.of(context).password_is_not_match_password_again;
                   }
                   return null;

lib/widgets/desktop/desktop_search_place.dart

@@ -128,7 +128,7 @@ class DesktopSearchPlaceState extends State<DesktopSearchPlace> {
     );
     if (result is DioError) {
       if (result.response != null) {
-        throw RuntimeError(result.response.data['message']);
+        throw RuntimeError(result.response!.data['message']);
       } else {
         throw RuntimeError(result.message);
       }

lib/widgets/desktop/desktop_set_password.dart

@@ -26,10 +26,10 @@ class DesktopSetPasswordState extends State<DesktopSetPassword> {
   final passwordController = TextEditingController();
   final passwordAgainController = TextEditingController();
 
-  bool passwordVisible;
-  bool passwordAgainVisible;
+  late bool passwordVisible;
+  late bool passwordAgainVisible;
 
-  bool canReset;
+  late bool canReset;
 
   double sideSpace = 0;
   double mainSpace = 1200;
@@ -93,7 +93,7 @@ class DesktopSetPasswordState extends State<DesktopSetPassword> {
                     fontSize: 18.0
                 ),
                 validator: (String? value) {
-                  if (value.trim().isEmpty) {
+                  if (value!.trim().isEmpty) {
                     return S.of(context).password_is_required;
                   }
                   return null;
@@ -147,10 +147,10 @@ class DesktopSetPasswordState extends State<DesktopSetPassword> {
                     fontSize: 18.0
                 ),
                 validator: (String? value) {
-                  if (value.trim().isEmpty) {
+                  if (value!.trim().isEmpty) {
                     return S.of(context).password_is_required;
                   }
-                  if (value.trim() != passwordController.text.trim()) {
+                  if (value!.trim() != passwordController.text.trim()) {
                     return S.of(context).password_is_not_match_password_again;
                   }
                   return null;

lib/widgets/desktop/desktop_shopping_cart_widget.dart

@@ -18,14 +18,14 @@ class DesktopShoppingCartWidget extends StatefulWidget {
 }
 
 class DesktopShoppingCartWidgetState extends State<DesktopShoppingCartWidget> {
-  CartInfo cartInfo;
+  late CartInfo cartInfo;
   double totalPrice = 0.0;
 
   @override
   Widget build(BuildContext context) {
     totalPrice = 0.0;
     cartInfo = Utils.getCartInfoByBusiness(store.state.cartInfos, widget.business);
-    if (cartInfo != null && cartInfo.businessInfo.id == widget.business.id) {
+    if (cartInfo != null && cartInfo.businessInfo!.id == widget.business.id) {
       totalPrice = cartInfo.getTotalPrice();
     }
     Row row = Row(

lib/widgets/desktop/desktop_store_product_search.dart

@@ -134,7 +134,7 @@ class DesktopStoreProductSearchState extends State<DesktopStoreProductSearch> {
     );
     if (result is DioError) {
       if (result.response != null) {
-        throw RuntimeError(result.response.data);
+        throw RuntimeError(result.response!.data);
       } else {
         throw RuntimeError(result.message);
       }

lib/widgets/desktop/desktop_user_profile.dart

@@ -27,10 +27,10 @@ class DesktopUserProfile extends StatefulWidget {
 }
 
 class DesktopUserProfileState extends State<DesktopUserProfile> {
-  User _user;
+  late User _user;
 
-  bool _showProgress;
-  double _progress;
+  late bool _showProgress;
+  late double _progress;
 
   double sideSpace = 0;
   double mainSpace = 1200;
@@ -253,7 +253,7 @@ class DesktopUserProfileState extends State<DesktopUserProfile> {
                         ),
                         Container(
                           child: Text(
-                            _user.mobile != null && _user.mobile.isNotEmpty ? Utils.safePhoneNumber(_user.mobile) : S.of(context).not_binding,
+                            _user.mobile != null && _user.mobile!.isNotEmpty ? Utils.safePhoneNumber(_user.mobile) : S.of(context).not_binding,
                             style: TextStyle(
                               color: Colors.grey,
                             ),
@@ -306,7 +306,7 @@ class DesktopUserProfileState extends State<DesktopUserProfile> {
                         ),
                         Container(
                           child: Text(
-                            _user.email != null && _user.email.isNotEmpty ? Utils.safePhoneNumber(_user.email) : S.of(context).not_binding,
+                            _user.email != null && _user.email!.isNotEmpty ? Utils.safePhoneNumber(_user.email) : S.of(context).not_binding,
                             style: TextStyle(
                               color: Colors.grey,
                             ),
@@ -425,7 +425,7 @@ class DesktopUserProfileState extends State<DesktopUserProfile> {
                   ),
                   autofocus: true,
                   validator: (String? value) {
-                    if (value.trim().isEmpty) {
+                    if (value!.trim().isEmpty) {
                       return S.of(context).nickname_is_required;
                     }
                     return null;

lib/widgets/desktop/desktop_view_blog.dart

@@ -28,7 +28,7 @@ class DesktopViewBlog extends StatefulWidget {
 }
 
 class DesktopViewBlogState extends State<DesktopViewBlog> {
-  Blog blog;
+  late Blog blog;
 
   double sideSpace = 0;
   double mainSpace = 1200;

lib/widgets/desktop/desktop_view_ticket.dart

@@ -33,7 +33,7 @@ class DesktopViewTicket extends StatefulWidget {
 class DesktopViewTicketState extends State<DesktopViewTicket> {
   final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
 
-  Ticket ticket;
+  late Ticket ticket;
 
   final issueMsgController = TextEditingController();
 
@@ -144,7 +144,7 @@ class DesktopViewTicketState extends State<DesktopViewTicket> {
               ),
               autofocus: false,
               validator: (String? value) {
-                if (value.trim().isEmpty) {
+                if (value!.trim().isEmpty) {
                   return S.of(context).this_field_is_required;
                 }
                 return null;
@@ -240,7 +240,7 @@ class DesktopViewTicketState extends State<DesktopViewTicket> {
           width: double.maxFinite,
           padding: EdgeInsets.only(top: 8.0, left: 16.0, right: 16.0, bottom: 24.0),
           child: Text(
-            '${ticket.issue.msg}',
+            '${ticket.issue!.msg}',
             style: TextStyle(
               color: Colors.black54,
               fontSize: 14.0,
@@ -260,7 +260,7 @@ class DesktopViewTicketState extends State<DesktopViewTicket> {
           padding: EdgeInsets.only(top: 16.0, bottom: 16.0, left: 16.0, right: 16.0),
           child: SingleChildScrollView(
             scrollDirection: Axis.horizontal,
-            child: showGalleryImages(mainContext, ticket.issue.files),
+            child: showGalleryImages(mainContext, ticket.issue!.files),
           ),
           decoration: BoxDecoration(
             border: Border(
@@ -291,7 +291,7 @@ class DesktopViewTicketState extends State<DesktopViewTicket> {
       ],
     );
 
-    if (ticket.followUps.length > 0) {
+    if (ticket.followUps!.length > 0) {
       ticketCol.children.add(
         Container(
           width: double.maxFinite,
@@ -305,8 +305,8 @@ class DesktopViewTicketState extends State<DesktopViewTicket> {
           ),
         ),
       );
-      for (int i = 0; i < ticket.followUps.length; i++) {
-        FollowUp followUp = ticket.followUps[i];
+      for (int i = 0; i < ticket.followUps!.length; i++) {
+        FollowUp followUp = ticket.followUps![i];
         ticketCol.children.add(
           Container(
             width: double.maxFinite,
@@ -423,7 +423,7 @@ class DesktopViewTicketState extends State<DesktopViewTicket> {
                           padding: EdgeInsets.only(left: 20.0, right: 20.0, top: 0.0, bottom: 30.0),
                           child: TextLink(
                             S.of(context).new_ticket,
-                            '/new-ticket/${ticket.store.id}',
+                            '/new-ticket/${ticket.store!.id}',
                           ),
                         )
                       ],
@@ -693,7 +693,7 @@ class DesktopViewTicketState extends State<DesktopViewTicket> {
                         child: Text(S.of(context).ok),
                         onPressed: () {
                           Routes.router.navigateTo(context,
-                            '/my-support/${ticket.store.id}',
+                            '/my-support/${ticket.store!.id}',
                             replace: true,
                           );
                         },

lib/widgets/desktop/product_item.dart

@@ -90,7 +90,7 @@ class ProductItemState extends State<ProductItem> {
           width: 110.0,
           height: 110.0,
           child: GestureDetector(
-            child: onHover && widget.product.secondImagePath.isNotEmpty ?
+            child: onHover && widget.product.secondImagePath!.isNotEmpty ?
             Util.showImage('${widget.product.secondImagePath}',
               fit: BoxFit.fill,
             ) :
@@ -143,7 +143,7 @@ class ProductItemState extends State<ProductItem> {
                       new Container(
                         child: widget.business.showMonthlySold ?
                         Text(
-                          S.of(context).sold_per_month_token(widget.product.monthSales.toStringAsFixed(0)),
+                          S.of(context).sold_per_month_token(widget.product.monthSales!.toStringAsFixed(0)),
                           style: new TextStyle(
                               fontSize: 9.0
                           ),
@@ -176,7 +176,7 @@ class ProductItemState extends State<ProductItem> {
           width: 110.0,
           height: 110.0,
           child: GestureDetector(
-            child: onHover && widget.product.secondImagePath.isNotEmpty ?
+            child: onHover && widget.product.secondImagePath!.isNotEmpty ?
             Util.showImage('${widget.product.secondImagePath}',
               fit: BoxFit.fill,
             ) :
@@ -231,7 +231,7 @@ class ProductItemState extends State<ProductItem> {
                       new Container(
                         child: widget.business.showMonthlySold ?
                         Text(
-                          S.of(context).sold_per_month_token(widget.product.monthSales.toStringAsFixed(0)),
+                          S.of(context).sold_per_month_token(widget.product.monthSales!.toStringAsFixed(0)),
                           style: new TextStyle(
                               fontSize: 9.0
                           ),

lib/widgets/desktop/product_search.dart

@@ -142,7 +142,7 @@ class ProductSearchState extends State<ProductSearch> {
     );
     if (result is DioError) {
       if (result.response != null) {
-        throw RuntimeError(result.response.data);
+        throw RuntimeError(result.response!.data);
       } else {
         throw RuntimeError(result.message);
       }

lib/widgets/desktop/shop.dart

@@ -32,13 +32,13 @@ class Shop extends StatefulWidget {
 }
 
 class ShopState extends State<Shop> {
-  Business _business;
+  late Business _business;
 
   PanelController panelController = PanelController();
-  SlidingUpPanel _slidUpShoppingCart;
+  late SlidingUpPanel _slidUpShoppingCart;
   GlobalKey endKey = GlobalKey();
 
-  List<CategoryProducts> _categoryProducts;
+  late List<CategoryProducts> _categoryProducts;
   bool displayProductByCategoryClick = false;
   String displayProductByCategoryClickIndicator = '';
   int categoryId = 0;
@@ -261,7 +261,7 @@ class ShopState extends State<Shop> {
             if (moreCategoryProducts.isEmpty) {
               _productCurrentPage = 0;
             } else {
-              if (moreCategoryProducts[0].products.length < Constants.ORDERS_PER_PAGE) {
+              if (moreCategoryProducts[0].products!.length < Constants.ORDERS_PER_PAGE) {
                 _productCurrentPage = 0;
               }
             }

lib/widgets/desktop/shop_bulletin.dart

@@ -28,7 +28,7 @@ class ShopBulletinState extends State<ShopBulletin> {
       sideSpace = (MediaQuery.of(context).size.width - 1200) / 2;
     }
 
-    if (widget.business.bulletin != null && widget.business.bulletin.isNotEmpty) {
+    if (widget.business.bulletin != null && widget.business.bulletin!.isNotEmpty) {
       return Container(
         margin: EdgeInsets.only(bottom: 12),
         child: Row(

lib/widgets/desktop/shop_products.dart

@@ -39,7 +39,7 @@ class ShopProductsState extends State<ShopProducts> {
 
   int _categoryIndex = 0;
   List<CategoryProducts> _categoryProducts = [];
-  Business _business;
+  late Business _business;
 
   double menuPosition = 0;
 
@@ -116,11 +116,11 @@ class ShopProductsState extends State<ShopProducts> {
             int qtyInCategory = 0;
             CartInfo cartInfo = Utils.getCartInfoByBusiness(store.state.cartInfos, _business);
             if (cartInfo != null &&
-                cartInfo.businessInfo.id == _business.id &&
+                cartInfo.businessInfo!.id == _business.id &&
                 cartInfo.productList != null) {
-              for (var i = 0; i < cartInfo.productList.length; i++) {
-                if (cartInfo.productList[i].product.categoryId == cp.id) {
-                  qtyInCategory += cartInfo.productList[i].quantity.ceil();
+              for (var i = 0; i < cartInfo.productList!.length; i++) {
+                if (cartInfo.productList![i].product!.categoryId == cp.id) {
+                  qtyInCategory += cartInfo.productList![i].quantity!.ceil();
                 }
               }
             }
@@ -205,7 +205,7 @@ class ShopProductsState extends State<ShopProducts> {
     );
     for (int i = 0; i < _categoryProducts.length; i++) {
       CategoryProducts cp = _categoryProducts[i];
-      if (cp.products.length > 0) {
+      if (cp.products!.length > 0) {
         col.children.add(new Container(
             height: _categoryDescHeight,
             padding: new EdgeInsets.symmetric(horizontal: 10.0),
@@ -239,7 +239,7 @@ class ShopProductsState extends State<ShopProducts> {
                           ),
                         ),
                         new Visibility(
-                            visible: cp.description.isNotEmpty,
+                            visible: cp.description!.isNotEmpty,
                             child: new Text(
                               cp.description,
                               overflow: TextOverflow.ellipsis,
@@ -253,8 +253,8 @@ class ShopProductsState extends State<ShopProducts> {
               ],
             )));
 
-        var it = cp.products.iterator;
-        for (int i = 0; i < cp.products.length; i++) {
+        var it = cp.products!.iterator;
+        for (int i = 0; i < cp.products!.length; i++) {
           var r1 = Row(
             mainAxisAlignment: MainAxisAlignment.start,
             children: [],
@@ -295,7 +295,7 @@ class ShopProductsState extends State<ShopProducts> {
               ),
             );
           } else if (categoryId > 0) {
-            if (cp.products.length < Constants.ORDERS_PER_PAGE) {
+            if (cp.products!.length < Constants.ORDERS_PER_PAGE) {
               col.children.add(
                 Container(
                   padding: EdgeInsets.all(12.0),
@@ -374,7 +374,7 @@ class ShopProductsState extends State<ShopProducts> {
                 .of(context)
                 .end_of_the_list;
           } else {
-            if (moreCategoryProducts[0].products.length <
+            if (moreCategoryProducts[0].products!.length <
                 Constants.ORDERS_PER_PAGE) {
               displayProductByCategoryClickIndicator = S
                   .of(context)
@@ -388,7 +388,7 @@ class ShopProductsState extends State<ShopProducts> {
             CategoryProducts currentCp =
             getCategoryProductByCategoryId(categoryId);
             if (currentCp != null) {
-              currentCp.products.addAll(moreCategoryProducts[0].products);
+              currentCp.products!.addAll(moreCategoryProducts[0].products);
             } else {
               displayProductByCategoryClickIndicator = S
                   .of(context)
@@ -403,7 +403,7 @@ class ShopProductsState extends State<ShopProducts> {
   int numCategoriesHasProducts() {
     int num = 0;
     for (CategoryProducts cp in _categoryProducts) {
-      if (cp.products.length > 0) {
+      if (cp.products!.length > 0) {
         num += 1;
       }
     }

lib/widgets/desktop/shop_promote.dart

@@ -22,7 +22,7 @@ class ShopPromoteState extends State<ShopPromote> {
   double sideSpace = 0;
   double mainSpace = 1200;
 
-  Business _business;
+  late Business _business;
 
   @override
   Widget build(BuildContext context) {
@@ -90,7 +90,7 @@ class ShopPromoteState extends State<ShopPromote> {
       mainAxisAlignment: MainAxisAlignment.start,
       children: <Widget>[],
     );
-    for (var i = 0; i < _business.promoProducts.length; i++) {
+    for (var i = 0; i < _business.promoProducts!.length; i++) {
       promotRow.children.add(Container(
         padding: EdgeInsets.only(
           left: 10.0,
@@ -129,17 +129,17 @@ class ShopPromoteState extends State<ShopPromote> {
             GestureDetector(
               child: Container(
                 child: Util.showImage(
-                  _business.promoProducts[i].imagePath,
+                  _business.promoProducts![i].imagePath,
                   width: 120.0,
                 ),
               ),
               onTap: () {
-                _showProductDetail(_business.promoProducts[i]);
+                _showProductDetail(_business.promoProducts![i]);
               },
             ),
             Container(
               child: Text(
-                _business.promoProducts[i].name,
+                _business.promoProducts![i].name,
                 maxLines: 2,
                 overflow: TextOverflow.ellipsis,
                 style: TextStyle(fontSize: 14.0),
@@ -149,16 +149,16 @@ class ShopPromoteState extends State<ShopPromote> {
               mainAxisAlignment: MainAxisAlignment.spaceBetween,
               children: <Widget>[
                 ShowPrice(
-                  _business.promoProducts[i].price,
+                  _business.promoProducts![i].price,
                   currencySign: '\$',
                   fontWeight: FontWeight.bold,
                   smallFontSize: 15,
                   largeFontSize: 24,
-                  regularPrice: _business.promoProducts[i].regularPrice,
+                  regularPrice: _business.promoProducts![i].regularPrice,
                 ),
                 Container(
                   child: AddRemoveButton(
-                    product: _business.promoProducts[i],
+                    product: _business.promoProducts![i],
                     business: _business,
                     addOnly: true,
                   ),

lib/widgets/desktop/shopping_cart_widget.dart

@@ -19,14 +19,14 @@ class ShoppingCartWidget extends StatefulWidget {
 }
 
 class ShoppingCartWidgetState extends State<ShoppingCartWidget> {
-  CartInfo cartInfo;
+  late CartInfo cartInfo;
   double totalPrice = 0.0;
 
   @override
   Widget build(BuildContext context) {
     totalPrice = 0.0;
     cartInfo = Utils.getCartInfoByBusiness(store.state.cartInfos, widget.business);
-    if (cartInfo != null && cartInfo.businessInfo.id == widget.business.id) {
+    if (cartInfo != null && cartInfo.businessInfo!.id == widget.business.id) {
       totalPrice = cartInfo.getTotalPrice();
     }
     Row row = Row(

lib/widgets/general/add_remove_button.dart

@@ -40,7 +40,7 @@ class AddRemoveButton extends StatefulWidget {
 }
 
 class AddRemoveButtonState extends State<AddRemoveButton> {
-  int _qty;
+  late int _qty;
   var zeroColor = const Color(0xFFEFEFEF);
   var qtyColor = const Color(0xFFFF6666);
   var zeroFontColor = const Color(0xFF888888);
@@ -48,7 +48,7 @@ class AddRemoveButtonState extends State<AddRemoveButton> {
 
   var d = 1;
 
-  CartInfo cartInfo;
+  late CartInfo cartInfo;
 
   GlobalKey startKey = GlobalKey();
 
@@ -63,10 +63,10 @@ class AddRemoveButtonState extends State<AddRemoveButton> {
       _qty = 0;
       cartInfo = Utils.getCartInfoByBusiness(store.state.cartInfos, widget.business);
       if (cartInfo != null) {
-        for (var i = 0; i < cartInfo.productList.length; i++) {
-          if (cartInfo.productList[i].product.id == widget.product.id
-              && cartInfo.productList[i].unitPrice == 0.0) {
-            _qty = cartInfo.productList[i].quantity.round();
+        for (var i = 0; i < cartInfo.productList!.length; i++) {
+          if (cartInfo.productList![i].product!.id == widget.product.id
+              && cartInfo.productList![i].unitPrice == 0.0) {
+            _qty = cartInfo.productList![i].quantity!.round();
             break;
           }
         }
@@ -78,7 +78,7 @@ class AddRemoveButtonState extends State<AddRemoveButton> {
         ),
       );
     }
-    if (widget.product.leftNum <= 0) {
+    if (widget.product.leftNum! <= 0) {
       return Container(
         padding: EdgeInsets.only(top: 0.0, bottom: 10.0, left: 8.0, right: 8.0),
         child: Text(
@@ -104,9 +104,9 @@ class AddRemoveButtonState extends State<AddRemoveButton> {
       _qty = 0;
       cartInfo = Utils.getCartInfoByBusiness(store.state.cartInfos, widget.business);
       if (cartInfo != null) {
-        for (var i = 0; i < cartInfo.productList.length; i++) {
-          if (cartInfo.productList[i].product.id == widget.product.id) {
-            _qty = cartInfo.productList[i].quantity.round();
+        for (var i = 0; i < cartInfo.productList!.length; i++) {
+          if (cartInfo.productList![i].product!.id == widget.product.id) {
+            _qty = cartInfo.productList![i].quantity!.round();
             break;
           }
         }
@@ -197,15 +197,15 @@ class AddRemoveButtonState extends State<AddRemoveButton> {
       _qty = 0;
       cartInfo = Utils.getCartInfoByBusiness(store.state.cartInfos, widget.business);
       if (cartInfo != null) {
-        for (var i = 0; i < cartInfo.productList.length; i++) {
-          if (cartInfo.productList[i].product.id == widget.product.id) {
-            _qty = cartInfo.productList[i].quantity.round();
+        for (var i = 0; i < cartInfo.productList!.length; i++) {
+          if (cartInfo.productList![i].product!.id == widget.product.id) {
+            _qty = cartInfo.productList![i].quantity!.round();
             break;
           }
         }
       }
       if (widget.product.productAttributes != null &&
-          widget.product.productAttributes.length > 0 && widget.cartLineItemIndex == -1) {
+          widget.product.productAttributes!.length > 0 && widget.cartLineItemIndex == -1) {
         return new Row(
           key: startKey,
           crossAxisAlignment: CrossAxisAlignment.end,
@@ -312,7 +312,7 @@ class AddRemoveButtonState extends State<AddRemoveButton> {
 
   void _addToCart(BuildContext context) {
     if (widget.cartLineItemIndex != -1) {
-      if (cartInfo.productList[widget.cartLineItemIndex].quantity + 1.0 > widget.product.leftNum) {
+      if (cartInfo.productList![widget.cartLineItemIndex].quantity! + 1.0 > widget.product.leftNum) {
         Fluttertoast.showToast(
             msg: S.of(context).product_insufficient,
             toastLength: Toast.LENGTH_SHORT,
@@ -321,14 +321,14 @@ class AddRemoveButtonState extends State<AddRemoveButton> {
             textColor: Colors.white
         );
       } else {
-        cartInfo.productList[widget.cartLineItemIndex].quantity += 1.0;
-        Utils.addSubproductQty(cartInfo, cartInfo.productList[widget.cartLineItemIndex]);
+        cartInfo.productList![widget.cartLineItemIndex].quantity += 1.0;
+        Utils.addSubproductQty(cartInfo, cartInfo.productList![widget.cartLineItemIndex]);
         store.dispatch(UpdateCartInfo(
             Utils.addCartInfoToCartInfoList(store.state.cartInfos, cartInfo)));
         eventBus.fire(new OnCartInfoUpdated());
       }
     } else {
-      if (widget.product.productAttributes.length > 0) {
+      if (widget.product.productAttributes!.length > 0) {
         Navigator.push(
           context,
           MaterialPageRoute(builder: (context) =>
@@ -345,7 +345,7 @@ class AddRemoveButtonState extends State<AddRemoveButton> {
 
   void _removeFromCart(BuildContext context) {
     if (widget.cartLineItemIndex != -1) {
-      if (cartInfo.productList[widget.cartLineItemIndex].quantity <= 1) {
+      if (cartInfo.productList![widget.cartLineItemIndex].quantity! <= 1) {
         showDialog(
             context: context,
             builder: (BuildContext context) {
@@ -380,15 +380,15 @@ class AddRemoveButtonState extends State<AddRemoveButton> {
   }
 
   void _removeCartLineItem() {
-    if (cartInfo.productList[widget.cartLineItemIndex].quantity <= 1) {
-      String uuid = cartInfo.productList[widget.cartLineItemIndex].uuid;
-      cartInfo.productList.removeAt(widget.cartLineItemIndex);
+    if (cartInfo.productList![widget.cartLineItemIndex].quantity! <= 1) {
+      String uuid = cartInfo.productList![widget.cartLineItemIndex].uuid;
+      cartInfo.productList!.removeAt(widget.cartLineItemIndex);
       Utils.removeSubproduct(cartInfo, uuid);
     } else {
-      cartInfo.productList[widget.cartLineItemIndex].quantity -= 1;
-      Utils.addSubproductQty(cartInfo, cartInfo.productList[widget.cartLineItemIndex], remove: true);
+      cartInfo.productList![widget.cartLineItemIndex].quantity -= 1;
+      Utils.addSubproductQty(cartInfo, cartInfo.productList![widget.cartLineItemIndex], remove: true);
     }
-    if (cartInfo.productList.length <= 0) {
+    if (cartInfo.productList!.length <= 0) {
       store.dispatch(new UpdateCartInfo(Utils.removeCartInfoFromCartInfoList(store.state.cartInfos, cartInfo)));
     } else {
       store.dispatch(new UpdateCartInfo(Utils.addCartInfoToCartInfoList(store.state.cartInfos, cartInfo)));

lib/widgets/general/animation_point_manager.dart

@@ -5,8 +5,8 @@ import 'popup_animation_widget.dart';
 
 class AnimationPointManager {
   List<AnimatedWidget> list = [];
-  static AnimationController controller1;
-  static AnimationController controller2;
+  static late AnimationController controller1;
+  static late AnimationController controller2;
 
   Future<void> addParabolicAniamtion({
     @required TickerProvider vsync,
@@ -55,9 +55,9 @@ class AnimationPointManager {
     @required GlobalKey stackKey,
     @required GlobalKey startKey,
     @required Widget child,
-    Duration duration,
+    Duration? duration,
     Offset popupOffset = Offset.zero,
-    AnimationStatusListener statusListener,
+    AnimationStatusListener? statusListener,
   }) async {
     controller2 = createController(vsync, duration);
 

lib/widgets/general/attribute/check_options.dart

@@ -50,14 +50,14 @@ class CheckOptionsState extends OptionsBaseState<CheckOptions> {
               crossAxisAlignment: CrossAxisAlignment.start,
               children: <Widget>[
                 new Text(
-                  S.of(context).check_option_select_token(product.productAttributes[this.index].name),
+                  S.of(context).check_option_select_token(product.productAttributes![this.index].name),
                   style: new TextStyle(
                     fontSize: 12.5,
                   ),
                   overflow: TextOverflow.ellipsis,
                 ),
                 new Text(
-                  product.productAttributes[this.index].required ? S.of(context).check_option_is_required : S.of(context).check_option_is_optional,
+                  product.productAttributes![this.index].required ? S.of(context).check_option_is_required : S.of(context).check_option_is_optional,
                   style: new TextStyle(
                     fontSize: 10.0,
                     color: new Color(0xFF999999)
@@ -95,20 +95,20 @@ class CheckOptionsState extends OptionsBaseState<CheckOptions> {
       'adjust_amount': adjustAmount
     };
     var cloneSelections = json.decode(json.encode(selections));
-    int idx = Utils.selectionsContains(cloneSelections, product.productAttributes[index].name, name);
+    int idx = Utils.selectionsContains(cloneSelections, product.productAttributes![index].name, name);
     if (idx != -1) {
-      (cloneSelections[product.productAttributes[index].name.toUpperCase()] as List).removeAt(idx);
-    } else if (cloneSelections.containsKey(product.productAttributes[index].name.toUpperCase())) {
-      (cloneSelections[product.productAttributes[index].name.toUpperCase()] as List).add(opt);
+      (cloneSelections[product.productAttributes![index].name!.toUpperCase()] as List).removeAt(idx);
+    } else if (cloneSelections.containsKey(product.productAttributes![index].name!.toUpperCase())) {
+      (cloneSelections[product.productAttributes![index].name!.toUpperCase()] as List).add(opt);
     } else {
-      cloneSelections[product.productAttributes[index].name.toUpperCase()] = [opt];
+      cloneSelections[product.productAttributes![index].name!.toUpperCase()] = [opt];
     }
 
-    if (idx != -1 && (cloneSelections[product.productAttributes[index].name.toUpperCase()] as List).length == 0) {
-      cloneSelections.remove(product.productAttributes[index].name.toUpperCase());
+    if (idx != -1 && (cloneSelections[product.productAttributes![index].name!.toUpperCase()] as List).length == 0) {
+      cloneSelections.remove(product.productAttributes![index].name!.toUpperCase());
     }
 
-    setOptionsStateDisabled(product.productAttributes[index].name, false);
+    setOptionsStateDisabled(product.productAttributes![index].name, false);
 
     setState(() {
       selections = cloneSelections;
@@ -121,20 +121,20 @@ class CheckOptionsState extends OptionsBaseState<CheckOptions> {
       children: <Widget>[],
     );
 
-    List<ProductOption> productOptions = product.productAttributes[index].productOptions;
+    List<ProductOption> productOptions = product.productAttributes![index].productOptions;
 
-    if (!optionsState.containsKey(product.productAttributes[index].name)) {
+    if (!optionsState.containsKey(product.productAttributes![index].name)) {
       List<Map<String, dynamic>> optionState = [];
       for (var i = 0; i < productOptions.length; i++) {
-        optionState.add({'name': product.productAttributes[index].productOptions[i].name, 'disabled': false, 'check': false});
+        optionState.add({'name': product.productAttributes![index].productOptions![i].name, 'disabled': false, 'check': false});
       }
-      optionsState[product.productAttributes[index].name] = optionState;
+      optionsState[product.productAttributes![index].name] = optionState;
     }
 
-    if (selections.containsKey(product.productAttributes[index].name.toUpperCase())) {
+    if (selections.containsKey(product.productAttributes![index].name!.toUpperCase())) {
 
       Map<String, dynamic> attrExtraJson = Utils.stringToJson(
-          product.productAttributes[index].extra);
+          product.productAttributes![index].extra);
       if (attrExtraJson != null) {
         var selectLimitIfFieldEqualsTo = Rule.getRule(
             attrExtraJson, Rule.RULE_SELECT_LIMIT_IF_FIELD_EQUALS_TO);
@@ -147,7 +147,7 @@ class CheckOptionsState extends OptionsBaseState<CheckOptions> {
                 int limitQty = selectLimitIfFieldEqualsTo1[Rule
                     .RULE_KEY_FORCE_LIMITED];
                 thisLimitQty = limitQty;
-                if ((selections[product.productAttributes[index].name
+                if ((selections[product.productAttributes![index].name
                     .toUpperCase()] as List).length >= limitQty) {
                   disableOptionIfNotSelected();
                 }
@@ -155,7 +155,7 @@ class CheckOptionsState extends OptionsBaseState<CheckOptions> {
                 if (selectLimitIfFieldEqualsTo1.containsKey(Utils.getSelectedAttributeValue(selections, selectLimitIfFieldEqualsTo1[Rule.RULE_KEY_FIELD_KEY])[0])) {
                   int limitQty = selectLimitIfFieldEqualsTo1[Utils.getSelectedAttributeValue(selections, selectLimitIfFieldEqualsTo1[Rule.RULE_KEY_FIELD_KEY])[0]];
                   thisLimitQty = limitQty;
-                  if ((selections[product.productAttributes[index].name
+                  if ((selections[product.productAttributes![index].name
                       .toUpperCase()] as List).length >= limitQty) {
                     disableOptionIfNotSelected();
                   }
@@ -168,7 +168,7 @@ class CheckOptionsState extends OptionsBaseState<CheckOptions> {
               int limitQty = selectLimitIfFieldEqualsTo[Rule
                   .RULE_KEY_FORCE_LIMITED];
               thisLimitQty = limitQty;
-              if ((selections[product.productAttributes[index].name
+              if ((selections[product.productAttributes![index].name
                   .toUpperCase()] as List).length >= limitQty) {
                 disableOptionIfNotSelected();
               }
@@ -176,7 +176,7 @@ class CheckOptionsState extends OptionsBaseState<CheckOptions> {
               if (selectLimitIfFieldEqualsTo.containsKey(Utils.getSelectedAttributeValue(selections, selectLimitIfFieldEqualsTo[Rule.RULE_KEY_FIELD_KEY])[0])) {
                 int limitQty = selectLimitIfFieldEqualsTo[Utils.getSelectedAttributeValue(selections, selectLimitIfFieldEqualsTo[Rule.RULE_KEY_FIELD_KEY])[0]];
                 thisLimitQty = limitQty;
-                if ((selections[product.productAttributes[index].name
+                if ((selections[product.productAttributes![index].name
                     .toUpperCase()] as List).length >= limitQty) {
                   disableOptionIfNotSelected();
                 }
@@ -195,12 +195,12 @@ class CheckOptionsState extends OptionsBaseState<CheckOptions> {
           Map<String, dynamic> multiItemRule = Rule.getRule(extraJson, Rule.RULE_ACTUAL_QTY_IS);
           if (exclusiveRule != null) {
             if (thisLimitQty > 0 && !_checkOptionIsCheck(productOptions[i].name)) {
-              optionsState[product.productAttributes[index].name][i]['disabled'] = true;
+              optionsState[product.productAttributes![index].name][i]['disabled'] = true;
             } else {
               if (_checkOptionIsCheck(productOptions[i].name)) {
                 setOptionsStateDisabled(
-                    product.productAttributes[index].name, true);
-                optionsState[product.productAttributes[index]
+                    product.productAttributes![index].name, true);
+                optionsState[product.productAttributes![index]
                     .name][i]['disabled'] = false;
                 break;
               }
@@ -208,12 +208,12 @@ class CheckOptionsState extends OptionsBaseState<CheckOptions> {
           }
           if (multiItemRule != null) {
             if (_checkOptionIsCheck(productOptions[i].name)) {
-              if (multiItemRule[Rule.RULE_ACTUAL_QTY_IS] > thisLimitQty - (selections[product.productAttributes[index].name.toUpperCase()] as List).length) {
+              if (multiItemRule[Rule.RULE_ACTUAL_QTY_IS] > thisLimitQty - (selections[product.productAttributes![index].name!.toUpperCase()] as List).length) {
                 disableOptionIfNotSelected();
               }
             } else {
-              if (multiItemRule[Rule.RULE_ACTUAL_QTY_IS] > thisLimitQty - (selections[product.productAttributes[index].name.toUpperCase()] as List).length) {
-                optionsState[product.productAttributes[index]
+              if (multiItemRule[Rule.RULE_ACTUAL_QTY_IS] > thisLimitQty - (selections[product.productAttributes![index].name!.toUpperCase()] as List).length) {
+                optionsState[product.productAttributes![index]
                     .name][i]['disabled'] = true;
               }
             }
@@ -222,26 +222,26 @@ class CheckOptionsState extends OptionsBaseState<CheckOptions> {
       }
     }
 
-    List<Map<String, dynamic>> optionState = optionsState[product.productAttributes[index].name];
+    List<Map<String, dynamic>> optionState = optionsState[product.productAttributes![index].name];
     for (var i = 0; i < optionState.length; i++) {
       Widget optionWidget = _getOptionCheck(
-          product.productAttributes[index].productOptions[i], optionState[i]['disabled'], i);
+          product.productAttributes![index].productOptions![i], optionState[i]['disabled'], i);
       row.children.add(optionWidget);
     }
     return row;
   }
 
   void disableOptionIfNotSelected() {
-    setOptionsStateDisabled(product.productAttributes[index].name, true);
-    for (var i = 0; i < optionsState[product.productAttributes[index].name].length; i++) {
-      if (Utils.selectionsContains(selections, product.productAttributes[index].name, optionsState[product.productAttributes[index].name][i]['name']) != -1) {
-        optionsState[product.productAttributes[index].name][i]['disabled'] = false;
+    setOptionsStateDisabled(product.productAttributes![index].name, true);
+    for (var i = 0; i < optionsState[product.productAttributes![index].name].length; i++) {
+      if (Utils.selectionsContains(selections, product.productAttributes![index].name, optionsState[product.productAttributes![index].name][i]['name']) != -1) {
+        optionsState[product.productAttributes![index].name][i]['disabled'] = false;
       }
     }
   }
 
   bool _checkOptionIsCheck(String name) {
-    if (Utils.selectionsContains(selections, product.productAttributes[index].name, name) != -1) {
+    if (Utils.selectionsContains(selections, product.productAttributes![index].name, name) != -1) {
       return true;
     }
     return false;
@@ -343,7 +343,7 @@ class CheckOptionsState extends OptionsBaseState<CheckOptions> {
               overflow: TextOverflow.ellipsis,
             ),
             new Text(
-              (productOption.adjustAmount + extraAdjustAmount) > 0 ? '+${(productOption.adjustAmount + extraAdjustAmount).toStringAsFixed(2)}' : '',
+              (productOption.adjustAmount! + extraAdjustAmount) > 0 ? '+${(productOption.adjustAmount! + extraAdjustAmount).toStringAsFixed(2)}' : '',
               style: new TextStyle(
                 fontSize: 11.0,
                 color: check ? selectedTextColor : new Color(0xFFABABAB),
@@ -354,7 +354,7 @@ class CheckOptionsState extends OptionsBaseState<CheckOptions> {
         ),
       ),
       onTap: () => disabled ? null : _onOptionTappedCallback(
-          productOption.name, 0, productOption.adjustAmount + extraAdjustAmount, optIndex, productOption),
+          productOption.name, 0, productOption.adjustAmount! + extraAdjustAmount, optIndex, productOption),
     );
   }
 

lib/widgets/general/attribute/options_base.dart

@@ -16,9 +16,9 @@ abstract class OptionsBase extends StatefulWidget {
 }
 
 abstract class OptionsBaseState<Base extends OptionsBase> extends State<Base> {
-  Product product;
-  Map<String, dynamic> selections;
-  int index;
+  late Product product;
+  late Map<String, dynamic> selections;
+  late int index;
 
   final Color disabledBackgroundColor = new Color(0xFFBCBCBC);
 

lib/widgets/general/attribute/qty_options.dart

@@ -41,14 +41,14 @@ class QtyOptionsState extends OptionsBaseState<QtyOptions> {
               crossAxisAlignment: CrossAxisAlignment.start,
               children: <Widget>[
                 new Text(
-                  S.of(context).check_option_select_token(product.productAttributes[this.index].name),
+                  S.of(context).check_option_select_token(product.productAttributes![this.index].name),
                   style: new TextStyle(
                     fontSize: 12.5,
                   ),
                   overflow: TextOverflow.ellipsis,
                 ),
                 new Text(
-                  product.productAttributes[this.index].required ? S.of(context).check_option_is_required : S.of(context).check_option_is_optional,
+                  product.productAttributes![this.index].required ? S.of(context).check_option_is_required : S.of(context).check_option_is_optional,
                   style: new TextStyle(
                     fontSize: 10.0,
                     color: new Color(0xFF999999)
@@ -86,33 +86,33 @@ class QtyOptionsState extends OptionsBaseState<QtyOptions> {
       'adjust_amount': adjustAmount
     };
     var cloneSelections = json.decode(json.encode(selections));
-    int idx = Utils.selectionsContains(cloneSelections, product.productAttributes[index].name, name);
+    int idx = Utils.selectionsContains(cloneSelections, product.productAttributes![index].name, name);
     if (idx != -1) {
       if (quantity == 1) {
-        cloneSelections[product.productAttributes[index].name.toUpperCase()][idx]['quantity'] += 1;
-        optionsState[product.productAttributes[index].name][optIndex]['quantity'] = cloneSelections[product.productAttributes[index].name.toUpperCase()][idx]['quantity'];
+        cloneSelections[product.productAttributes![index].name!.toUpperCase()][idx]['quantity'] += 1;
+        optionsState[product.productAttributes![index].name][optIndex]['quantity'] = cloneSelections[product.productAttributes![index].name!.toUpperCase()][idx]['quantity'];
       } else {
-        if (cloneSelections[product.productAttributes[index].name.toUpperCase()][idx]['quantity'] - 1 > 0) {
-          cloneSelections[product.productAttributes[index].name.toUpperCase()][idx]['quantity'] -= 1;
-          optionsState[product.productAttributes[index].name][optIndex]['quantity'] = cloneSelections[product.productAttributes[index].name.toUpperCase()][idx]['quantity'];
+        if (cloneSelections[product.productAttributes![index].name!.toUpperCase()][idx]['quantity'] - 1 > 0) {
+          cloneSelections[product.productAttributes![index].name!.toUpperCase()][idx]['quantity'] -= 1;
+          optionsState[product.productAttributes![index].name][optIndex]['quantity'] = cloneSelections[product.productAttributes![index].name!.toUpperCase()][idx]['quantity'];
         } else {
-          (cloneSelections[product.productAttributes[index].name.toUpperCase()] as List).removeAt(idx);
-          optionsState[product.productAttributes[index].name][optIndex]['quantity'] = 0;
+          (cloneSelections[product.productAttributes![index].name!.toUpperCase()] as List).removeAt(idx);
+          optionsState[product.productAttributes![index].name][optIndex]['quantity'] = 0;
         }
       }
-    } else if (cloneSelections.containsKey(product.productAttributes[index].name.toUpperCase())) {
-      (cloneSelections[product.productAttributes[index].name.toUpperCase()] as List).add(opt);
-      optionsState[product.productAttributes[index].name][optIndex]['quantity'] = 1;
+    } else if (cloneSelections.containsKey(product.productAttributes![index].name!.toUpperCase())) {
+      (cloneSelections[product.productAttributes![index].name!.toUpperCase()] as List).add(opt);
+      optionsState[product.productAttributes![index].name][optIndex]['quantity'] = 1;
     } else {
-      cloneSelections[product.productAttributes[index].name.toUpperCase()] = [opt];
-      optionsState[product.productAttributes[index].name][optIndex]['quantity'] = 1;
+      cloneSelections[product.productAttributes![index].name!.toUpperCase()] = [opt];
+      optionsState[product.productAttributes![index].name][optIndex]['quantity'] = 1;
     }
 
-    if (idx != -1 && (cloneSelections[product.productAttributes[index].name.toUpperCase()] as List).length == 0) {
-      cloneSelections.remove(product.productAttributes[index].name.toUpperCase());
+    if (idx != -1 && (cloneSelections[product.productAttributes![index].name!.toUpperCase()] as List).length == 0) {
+      cloneSelections.remove(product.productAttributes![index].name!.toUpperCase());
     }
 
-    setOptionsStateDisabled(product.productAttributes[index].name, false);
+    setOptionsStateDisabled(product.productAttributes![index].name, false);
 
     setState(() {
       selections = cloneSelections;
@@ -125,24 +125,24 @@ class QtyOptionsState extends OptionsBaseState<QtyOptions> {
       children: <Widget>[],
     );
 
-    List<ProductOption> productOptions = product.productAttributes[index].productOptions;
+    List<ProductOption> productOptions = product.productAttributes![index].productOptions;
 
-    if (!optionsState.containsKey(product.productAttributes[index].name)) {
+    if (!optionsState.containsKey(product.productAttributes![index].name)) {
       List<Map<String, dynamic>> optionState = [];
       for (var i = 0; i < productOptions.length; i++) {
         int qty = 0;
-        int idx = Utils.selectionsContains(selections, product.productAttributes[index].name, productOptions[i].name);
+        int idx = Utils.selectionsContains(selections, product.productAttributes![index].name, productOptions[i].name);
         if (idx != -1) {
-          qty = selections[product.productAttributes[index].name.toUpperCase()][idx]['quantity'];
+          qty = selections[product.productAttributes![index].name!.toUpperCase()][idx]['quantity'];
         }
-        optionState.add({'name': product.productAttributes[index].productOptions[i].name, 'disabled': false, 'quantity': qty, 'check': false});
+        optionState.add({'name': product.productAttributes![index].productOptions![i].name, 'disabled': false, 'quantity': qty, 'check': false});
       }
-      optionsState[product.productAttributes[index].name] = optionState;
+      optionsState[product.productAttributes![index].name] = optionState;
     }
 
-    if (selections.containsKey(product.productAttributes[index].name.toUpperCase())) {
+    if (selections.containsKey(product.productAttributes![index].name!.toUpperCase())) {
       Map<String, dynamic> attrExtraJson = Utils.stringToJson(
-          product.productAttributes[index].extra);
+          product.productAttributes![index].extra);
       if (attrExtraJson != null) {
         var selectLimitIfFieldEqualsTo = Rule.getRule(
             attrExtraJson, Rule.RULE_SELECT_LIMIT_IF_FIELD_EQUALS_TO);
@@ -155,7 +155,7 @@ class QtyOptionsState extends OptionsBaseState<QtyOptions> {
                 int limitQty = selectLimitIfFieldEqualsTo1[Rule
                     .RULE_KEY_FORCE_LIMITED];
                 thisLimitQty = limitQty;
-                if ((selections[product.productAttributes[index].name
+                if ((selections[product.productAttributes![index].name
                     .toUpperCase()] as List).length >= limitQty) {
                   disableOptionIfNotSelected();
                 }
@@ -163,7 +163,7 @@ class QtyOptionsState extends OptionsBaseState<QtyOptions> {
                 if (selectLimitIfFieldEqualsTo1.containsKey(Utils.getSelectedAttributeValue(selections, selectLimitIfFieldEqualsTo1[Rule.RULE_KEY_FIELD_KEY])[0])) {
                   int limitQty = selectLimitIfFieldEqualsTo1[Utils.getSelectedAttributeValue(selections, selectLimitIfFieldEqualsTo1[Rule.RULE_KEY_FIELD_KEY])[0]];
                   thisLimitQty = limitQty;
-                  if ((selections[product.productAttributes[index].name
+                  if ((selections[product.productAttributes![index].name
                       .toUpperCase()] as List).length >= limitQty) {
                     disableOptionIfNotSelected();
                   }
@@ -176,7 +176,7 @@ class QtyOptionsState extends OptionsBaseState<QtyOptions> {
               int limitQty = selectLimitIfFieldEqualsTo[Rule
                   .RULE_KEY_FORCE_LIMITED];
               thisLimitQty = limitQty;
-              if ((selections[product.productAttributes[index].name
+              if ((selections[product.productAttributes![index].name
                   .toUpperCase()] as List).length >= limitQty) {
                 disableOptionIfNotSelected();
               }
@@ -184,7 +184,7 @@ class QtyOptionsState extends OptionsBaseState<QtyOptions> {
               if (selectLimitIfFieldEqualsTo.containsKey(Utils.getSelectedAttributeValue(selections, selectLimitIfFieldEqualsTo[Rule.RULE_KEY_FIELD_KEY])[0])) {
                 int limitQty = selectLimitIfFieldEqualsTo[Utils.getSelectedAttributeValue(selections, selectLimitIfFieldEqualsTo[Rule.RULE_KEY_FIELD_KEY])[0]];
                 thisLimitQty = limitQty;
-                if ((selections[product.productAttributes[index].name
+                if ((selections[product.productAttributes![index].name
                     .toUpperCase()] as List).length >= limitQty) {
                   disableOptionIfNotSelected();
                 }
@@ -203,12 +203,12 @@ class QtyOptionsState extends OptionsBaseState<QtyOptions> {
           Map<String, dynamic> multiItemRule = Rule.getRule(extraJson, Rule.RULE_ACTUAL_QTY_IS);
           if (exclusiveRule != null) {
             if (thisLimitQty > 0 && !_checkOptionIsCheck(productOptions[i].name)) {
-              optionsState[product.productAttributes[index].name][i]['disabled'] = true;
+              optionsState[product.productAttributes![index].name][i]['disabled'] = true;
             } else {
               if (_checkOptionIsCheck(productOptions[i].name)) {
                 setOptionsStateDisabled(
-                    product.productAttributes[index].name, true);
-                optionsState[product.productAttributes[index]
+                    product.productAttributes![index].name, true);
+                optionsState[product.productAttributes![index]
                     .name][i]['disabled'] = false;
                 break;
               }
@@ -216,12 +216,12 @@ class QtyOptionsState extends OptionsBaseState<QtyOptions> {
           }
           if (multiItemRule != null) {
             if (_checkOptionIsCheck(productOptions[i].name)) {
-              if (multiItemRule[Rule.RULE_ACTUAL_QTY_IS] > thisLimitQty - (selections[product.productAttributes[index].name.toUpperCase()] as List).length) {
+              if (multiItemRule[Rule.RULE_ACTUAL_QTY_IS] > thisLimitQty - (selections[product.productAttributes![index].name!.toUpperCase()] as List).length) {
                 disableOptionIfNotSelected();
               }
             } else {
-              if (multiItemRule[Rule.RULE_ACTUAL_QTY_IS] > thisLimitQty - (selections[product.productAttributes[index].name.toUpperCase()] as List).length) {
-                optionsState[product.productAttributes[index]
+              if (multiItemRule[Rule.RULE_ACTUAL_QTY_IS] > thisLimitQty - (selections[product.productAttributes![index].name!.toUpperCase()] as List).length) {
+                optionsState[product.productAttributes![index]
                     .name][i]['disabled'] = true;
               }
             }
@@ -230,26 +230,26 @@ class QtyOptionsState extends OptionsBaseState<QtyOptions> {
       }
     }
 
-    List<Map<String, dynamic>> optionState = optionsState[product.productAttributes[index].name];
+    List<Map<String, dynamic>> optionState = optionsState[product.productAttributes![index].name];
     for (var i = 0; i < optionState.length; i++) {
       Widget optionWidget = _getOptionQty(
-          product.productAttributes[index].productOptions[i], optionState[i]['disabled'], optionState[i]['quantity'], i);
+          product.productAttributes![index].productOptions![i], optionState[i]['disabled'], optionState[i]['quantity'], i);
       row.children.add(optionWidget);
     }
     return row;
   }
 
   void disableOptionIfNotSelected() {
-    setOptionsStateDisabled(product.productAttributes[index].name, true);
-    for (var i = 0; i < optionsState[product.productAttributes[index].name].length; i++) {
-      if (Utils.selectionsContains(selections, product.productAttributes[index].name, optionsState[product.productAttributes[index].name][i]['name']) != -1) {
-        optionsState[product.productAttributes[index].name][i]['disabled'] = false;
+    setOptionsStateDisabled(product.productAttributes![index].name, true);
+    for (var i = 0; i < optionsState[product.productAttributes![index].name].length; i++) {
+      if (Utils.selectionsContains(selections, product.productAttributes![index].name, optionsState[product.productAttributes![index].name][i]['name']) != -1) {
+        optionsState[product.productAttributes![index].name][i]['disabled'] = false;
       }
     }
   }
 
   bool _checkOptionIsCheck(String name) {
-    if (Utils.selectionsContains(selections, product.productAttributes[index].name, name) != -1) {
+    if (Utils.selectionsContains(selections, product.productAttributes![index].name, name) != -1) {
       return true;
     }
     return false;
@@ -361,7 +361,7 @@ class QtyOptionsState extends OptionsBaseState<QtyOptions> {
                     overflow: TextOverflow.ellipsis,
                   ),
                   new Text(
-                    (productOption.adjustAmount + extraAdjustAmount) > 0 ? '+${(productOption.adjustAmount + extraAdjustAmount).toStringAsFixed(2)}' : '',
+                    (productOption.adjustAmount! + extraAdjustAmount) > 0 ? '+${(productOption.adjustAmount! + extraAdjustAmount).toStringAsFixed(2)}' : '',
                     style: new TextStyle(
                       fontSize: 11.0,
                       color: check ? selectedTextColor : new Color(0xFFABABAB),
@@ -372,7 +372,7 @@ class QtyOptionsState extends OptionsBaseState<QtyOptions> {
               ),
             ),
             onTap: () => disabled ? null : _onOptionTappedCallback(
-                productOption.name, 1, productOption.adjustAmount + extraAdjustAmount, optIndex, productOption),
+                productOption.name, 1, productOption.adjustAmount! + extraAdjustAmount, optIndex, productOption),
           ),
           new Container(
             width: 100.0,
@@ -406,7 +406,7 @@ class QtyOptionsState extends OptionsBaseState<QtyOptions> {
                       ),
                     ),
                     onTap: () => disabled ? null : _onOptionTappedCallback(
-                        productOption.name, 1, productOption.adjustAmount + extraAdjustAmount, optIndex, productOption),
+                        productOption.name, 1, productOption.adjustAmount! + extraAdjustAmount, optIndex, productOption),
                   ),
                 ),
                 new Expanded(
@@ -420,7 +420,7 @@ class QtyOptionsState extends OptionsBaseState<QtyOptions> {
                       ),
                     ),
                     onTap: () => (disabled || quantity == 0) ? null : _onOptionTappedCallback(
-                        productOption.name, -1, productOption.adjustAmount + extraAdjustAmount, optIndex, productOption),
+                        productOption.name, -1, productOption.adjustAmount! + extraAdjustAmount, optIndex, productOption),
                   ),
                 ),
               ],

lib/widgets/general/attribute/radio_options.dart

@@ -40,14 +40,14 @@ class RadioOptionsState extends OptionsBaseState<RadioOptions> {
               crossAxisAlignment: CrossAxisAlignment.start,
               children: <Widget>[
                 new Text(
-                  S.of(context).radio_option_select_token(product.productAttributes[this.index].name),
+                  S.of(context).radio_option_select_token(product.productAttributes![this.index].name),
                   style: new TextStyle(
                     fontSize: 12.5,
                   ),
                   overflow: TextOverflow.ellipsis,
                 ),
                 new Text(
-                  product.productAttributes[this.index].required ? S.of(context).radio_option_is_required : S.of(context).radio_option_is_optional,
+                  product.productAttributes![this.index].required ? S.of(context).radio_option_is_required : S.of(context).radio_option_is_optional,
                   style: new TextStyle(
                     fontSize: 10.0,
                     color: new Color(0xFF999999)
@@ -85,14 +85,14 @@ class RadioOptionsState extends OptionsBaseState<RadioOptions> {
       'adjust_amount': adjustAmount
     };
     var cloneSelections = json.decode(json.encode(selections));
-    if (product.productAttributes[index].required) {
-      cloneSelections[product.productAttributes[index].name.toUpperCase()] = [opt];
+    if (product.productAttributes![index].required) {
+      cloneSelections[product.productAttributes![index].name!.toUpperCase()] = [opt];
     } else {
-      if (cloneSelections.containsKey(product.productAttributes[index].name.toUpperCase())
-          && Utils.equalsIgnoreCase(cloneSelections[product.productAttributes[index].name.toUpperCase()][0]['name'], name)) {
-        cloneSelections.remove(product.productAttributes[index].name.toUpperCase());
+      if (cloneSelections.containsKey(product.productAttributes![index].name!.toUpperCase())
+          && Utils.equalsIgnoreCase(cloneSelections[product.productAttributes![index].name!.toUpperCase()][0]['name'], name)) {
+        cloneSelections.remove(product.productAttributes![index].name!.toUpperCase());
       } else {
-        cloneSelections[product.productAttributes[index].name.toUpperCase()] = [opt];
+        cloneSelections[product.productAttributes![index].name!.toUpperCase()] = [opt];
       }
     }
 
@@ -102,7 +102,7 @@ class RadioOptionsState extends OptionsBaseState<RadioOptions> {
           extraJson, Rule.RULE_EXCLUSIVE_SELECTION);
       if (exclusiveRule != null) {
         if (_checkOptionIsCheck(productOption.name)) {
-          setOptionsStateDisabled(product.productAttributes[index].name, false);
+          setOptionsStateDisabled(product.productAttributes![index].name, false);
         }
       }
     }
@@ -118,14 +118,14 @@ class RadioOptionsState extends OptionsBaseState<RadioOptions> {
       children: <Widget>[],
     );
 
-    List<ProductOption> productOptions = product.productAttributes[index].productOptions;
+    List<ProductOption> productOptions = product.productAttributes![index].productOptions;
 
-    if (!optionsState.containsKey(product.productAttributes[index].name)) {
+    if (!optionsState.containsKey(product.productAttributes![index].name)) {
       List<Map<String, dynamic>> optionState = [];
       for (var i = 0; i < productOptions.length; i++) {
-        optionState.add({'name': product.productAttributes[index].productOptions[i].name, 'disabled': false, 'check': false});
+        optionState.add({'name': product.productAttributes![index].productOptions![i].name, 'disabled': false, 'check': false});
       }
-      optionsState[product.productAttributes[index].name] = optionState;
+      optionsState[product.productAttributes![index].name] = optionState;
     }
 
     for (var i = 0; i < productOptions.length; i++) {
@@ -135,25 +135,25 @@ class RadioOptionsState extends OptionsBaseState<RadioOptions> {
             extraJson, Rule.RULE_EXCLUSIVE_SELECTION);
         if (exclusiveRule != null) {
           if (_checkOptionIsCheck(productOptions[i].name)) {
-            setOptionsStateDisabled(product.productAttributes[index].name, true);
-            optionsState[product.productAttributes[index].name][i]['disabled'] = false;
+            setOptionsStateDisabled(product.productAttributes![index].name, true);
+            optionsState[product.productAttributes![index].name][i]['disabled'] = false;
             break;
           }
         }
       }
     }
 
-    List<Map<String, dynamic>> optionState = optionsState[product.productAttributes[index].name];
+    List<Map<String, dynamic>> optionState = optionsState[product.productAttributes![index].name];
     for (var i = 0; i < optionState.length; i++) {
       Widget optionWidget = _getOptionRadio(
-          product.productAttributes[index].productOptions[i], optionState[i]['disabled'], i);
+          product.productAttributes![index].productOptions![i], optionState[i]['disabled'], i);
       row.children.add(optionWidget);
     }
     return row;
   }
 
   bool _checkOptionIsCheck(String name) {
-    if (Utils.selectionsContains(selections, product.productAttributes[index].name, name) != -1) {
+    if (Utils.selectionsContains(selections, product.productAttributes![index].name, name) != -1) {
       return true;
     }
     return false;
@@ -255,7 +255,7 @@ class RadioOptionsState extends OptionsBaseState<RadioOptions> {
               overflow: TextOverflow.ellipsis,
             ),
             new Text(
-              (productOption.adjustAmount + extraAdjustAmount) > 0 ? '+${(productOption.adjustAmount + extraAdjustAmount).toStringAsFixed(2)}' : '',
+              (productOption.adjustAmount! + extraAdjustAmount) > 0 ? '+${(productOption.adjustAmount! + extraAdjustAmount).toStringAsFixed(2)}' : '',
               style: new TextStyle(
                 fontSize: 11.0,
                 color: check ? selectedTextColor : new Color(0xFFABABAB),
@@ -266,7 +266,7 @@ class RadioOptionsState extends OptionsBaseState<RadioOptions> {
         ),
       ),
       onTap: () => disabled ? null : _onOptionTappedCallback(
-          productOption.name, 0, productOption.adjustAmount + extraAdjustAmount, optIndex, productOption),
+          productOption.name, 0, productOption.adjustAmount! + extraAdjustAmount, optIndex, productOption),
     );
   }
 

lib/widgets/general/carousel.dart

@@ -6,8 +6,8 @@ import 'style.dart';
 class Carousel extends StatefulWidget {
   Carousel({
     double height = 200.0,
-    List<Widget> pages,
-    bool autoPlay,
+    List<Widget>? pages,
+    bool? autoPlay,
     Duration duration = const Duration(seconds: 2),
     Duration animationDuration = const Duration(milliseconds: 1000),
   })
@@ -30,7 +30,7 @@ class Carousel extends StatefulWidget {
 class CarouselState extends State<Carousel> {
   final _pageController = new PageController();
 
-  Timer _timer;
+  late Timer _timer;
   int _currentPage = 0;
   bool reverse = false;
   GlobalKey<IndicatorState> _indicatorStateKey = new GlobalKey();
@@ -80,7 +80,7 @@ class CarouselState extends State<Carousel> {
             children: widget.pages,
             onPageChanged: (index) {
               _currentPage = index;
-              _indicatorStateKey.currentState.changeIndex(index);
+              _indicatorStateKey.currentState!.changeIndex(index);
             },
           ),
         ),
@@ -102,7 +102,7 @@ class CarouselState extends State<Carousel> {
 }
 
 class Indicator extends StatefulWidget {
-  Indicator({Key? key, int count})
+  Indicator({Key? key, int? count})
       : count = count,
         super(key: key);
 

lib/widgets/general/e_transfer_pay.dart

@@ -65,7 +65,7 @@ class ETransferPay extends StatelessWidget {
                             fontSize: 15, color: Colors.black54),
                       ),
                       Text(
-                        '\$${order.totalPrice.toStringAsFixed(2)}',
+                        '\$${order.totalPrice!.toStringAsFixed(2)}',
                         style: const TextStyle(
                           fontSize: 28,
                           fontWeight: FontWeight.bold,

lib/widgets/general/parabolic_animation_widget.dart

@@ -11,7 +11,7 @@ class ParabolicAnimationWidget extends AnimatedWidget {
   final Offset startAdjustOffset;
   final Offset endAdjustOffset;
 
-  ParabolicAnimationWidget({
+  late ParabolicAnimationWidget({
     @required Animation<double> animation,
     @required this.stackKey,
     @required this.startKey,
@@ -66,17 +66,17 @@ class ParabolicAnimationWidget extends AnimatedWidget {
 
   void _calPoints() {
     if (_startOffset == null) {
-      RenderBox stackBox = stackKey.currentContext.findRenderObject();
+      RenderBox stackBox = stackKey.currentContext!.findRenderObject();
       Offset stackBoxOffset = stackBox.globalToLocal(Offset.zero);
 
       EdgeInsets startMargin = _margin(startKey);
-      RenderBox startBox = startKey.currentContext.findRenderObject();
+      RenderBox startBox = startKey.currentContext!.findRenderObject();
       _startOffset = startBox.localToGlobal(Offset(
           startMargin.left + startAdjustOffset.dx,
           stackBoxOffset.dy + startMargin.top + startAdjustOffset.dy));
 
       EdgeInsets endMargin = _margin(endKey);
-      RenderBox endBox = endKey.currentContext.findRenderObject();
+      RenderBox endBox = endKey.currentContext!.findRenderObject();
       _endOffset = endBox.localToGlobal(Offset(
           endMargin.left + endAdjustOffset.dx,
           stackBoxOffset.dy + endMargin.top + endAdjustOffset.dy));
@@ -84,7 +84,7 @@ class ParabolicAnimationWidget extends AnimatedWidget {
   }
 
   EdgeInsets _margin(GlobalKey key) {
-    final Widget widget = key.currentContext.widget;
+    final Widget widget = key.currentContext!.widget;
     EdgeInsets margin = (widget is Container) ? widget.margin : EdgeInsets.zero;
     return margin ?? EdgeInsets.zero;
   }

lib/widgets/general/payment_verification_code_dialog.dart

@@ -33,8 +33,8 @@ class PaymentVerificationCodeDialogState extends State<PaymentVerificationCodeDi
   String getCodeText = '';
   String paymentCodeEncrypt = '';
 
-  String verifyMethod;
-  String verifyName;
+  late String verifyMethod;
+  late String verifyName;
 
   final TextEditingController _pinPutController = TextEditingController();
   final FocusNode _pinPutFocusNode = FocusNode();

lib/widgets/general/popup_animation_widget.dart

@@ -9,7 +9,7 @@ class PopupAnimationWidget extends AnimatedWidget {
   final Offset popupOffset;
   final Animation<double> animation;
 
-  PopupAnimationWidget({
+  late PopupAnimationWidget({
     @required this.animation,
     @required this.stackKey,
     @required this.startKey,
@@ -49,11 +49,11 @@ class PopupAnimationWidget extends AnimatedWidget {
 
   void _calAnimation() {
     if (_startOffset == null) {
-      final RenderBox stackBox = stackKey.currentContext.findRenderObject();
+      final RenderBox stackBox = stackKey.currentContext!.findRenderObject();
       final Offset stackBoxOffset = stackBox.globalToLocal(Offset.zero);
 
       final EdgeInsets startMargin = _margin(startKey);
-      final RenderBox startBox = startKey.currentContext.findRenderObject();
+      final RenderBox startBox = startKey.currentContext!.findRenderObject();
 
       _startOffset = startBox.localToGlobal(Offset(
           startMargin.left + popupOffset.dx,
@@ -62,7 +62,7 @@ class PopupAnimationWidget extends AnimatedWidget {
   }
 
   EdgeInsets _margin(GlobalKey key) {
-    final Widget widget = key.currentContext.widget;
+    final Widget widget = key.currentContext!.widget;
     final EdgeInsets margin =
     (widget is Container) ? widget.margin : EdgeInsets.zero;
     return margin ?? EdgeInsets.zero;

lib/widgets/general/sliding_up_panel.dart

@@ -211,9 +211,9 @@ class SlidingUpPanel extends StatefulWidget {
 
 class _SlidingUpPanelState extends State<SlidingUpPanel> with SingleTickerProviderStateMixin{
 
-  AnimationController _ac;
+  late AnimationController _ac;
 
-  ScrollController _sc;
+  late ScrollController _sc;
   bool _scrollingEnabled = false;
   VelocityTracker _vt = VelocityTracker.withKind(PointerDeviceKind.touch);
 
@@ -390,7 +390,7 @@ class _SlidingUpPanelState extends State<SlidingUpPanel> with SingleTickerProvid
   // and a listener if panelBuilder is used.
   // this is because the listener is designed only for use with linking the scrolling of
   // panels and using it for panels that don't want to linked scrolling yields odd results
-  Widget _gestureHandler({Widget child}){
+  Widget _gestureHandler({Widget? child}){
     if (!widget.isDraggable) return child;
 
     if (widget.panel != null){
@@ -552,14 +552,14 @@ class _SlidingUpPanelState extends State<SlidingUpPanel> with SingleTickerProvid
 
   //animate the panel position to value - must
   //be between 0.0 and 1.0
-  Future<void> _animatePanelToPosition(double value, {Duration duration, Curve curve = Curves.linear}){
+  Future<void> _animatePanelToPosition(double value, {Duration? duration, Curve curve = Curves.linear}){
     assert(0.0 <= value && value <= 1.0);
     return _ac.animateTo(value, duration: duration, curve: curve);
   }
 
   //animate the panel position to the snap point
   //REQUIRES that widget.snapPoint != null
-  Future<void> _animatePanelToSnapPoint({Duration duration, Curve curve = Curves.linear}){
+  Future<void> _animatePanelToSnapPoint({Duration? duration, Curve curve = Curves.linear}){
     assert(widget.snapPoint != null);
     return _ac.animateTo(widget.snapPoint, duration: duration, curve: curve);
   }
@@ -602,7 +602,7 @@ class _SlidingUpPanelState extends State<SlidingUpPanel> with SingleTickerProvid
 
 
 class PanelController{
-  _SlidingUpPanelState _panelState;
+  late _SlidingUpPanelState _panelState;
 
   void _addState(_SlidingUpPanelState panelState){
     this._panelState = panelState;
@@ -644,7 +644,7 @@ class PanelController{
   /// where 0.0 is fully collapsed and 1.0 is completely open.
   /// (optional) duration specifies the time for the animation to complete
   /// (optional) curve specifies the easing behavior of the animation.
-  Future<void> animatePanelToPosition(double value, {Duration duration, Curve curve = Curves.linear}){
+  Future<void> animatePanelToPosition(double value, {Duration? duration, Curve curve = Curves.linear}){
     assert(isAttached, "PanelController must be attached to a SlidingUpPanel");
     assert(0.0 <= value && value <= 1.0);
     return _panelState._animatePanelToPosition(value, duration: duration, curve: curve);
@@ -654,7 +654,7 @@ class PanelController{
   /// Requires that the SlidingUpPanel snapPoint property is not null
   /// (optional) duration specifies the time for the animation to complete
   /// (optional) curve specifies the easing behavior of the animation.
-  Future<void> animatePanelToSnapPoint({Duration duration, Curve curve = Curves.linear}){
+  Future<void> animatePanelToSnapPoint({Duration? duration, Curve curve = Curves.linear}){
     assert(isAttached, "PanelController must be attached to a SlidingUpPanel");
     assert(_panelState.widget.snapPoint != null, "SlidingUpPanel snapPoint property must not be null");
     return _panelState._animatePanelToSnapPoint(duration: duration, curve: curve);

lib/widgets/mobile/create_online_store_1.dart

@@ -30,12 +30,12 @@ class CreateOnlineStore1State extends State<CreateOnlineStore1> {
   bool canSubmit = false;
 
   List<dynamic> stores = [];
-  Map<String, dynamic> service;
+  late Map<String, dynamic> service;
   dynamic selectedStore;
 
-  Group group;
+  late Group group;
 
-  String selectedDomain;
+  late String selectedDomain;
   List<dynamic> domainResult = [];
 
   @override
@@ -231,7 +231,7 @@ class CreateOnlineStore1State extends State<CreateOnlineStore1> {
                     ),
                     autofocus: true,
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         return S.of(context).domains_separated_comma;
                       }
                       return null;

lib/widgets/mobile/mobile_attribute_selection.dart

@@ -33,18 +33,18 @@ class MobileAttributeSelection extends StatefulWidget {
 }
 
 class MobileAttributeSelectionState extends State<MobileAttributeSelection> {
-  Product product;
-  int index;
-  TextButton previousButton;
-  TextButton nextButton;
-  bool previousButtonEnable;
-  bool nextButtonEnable;
+  late Product product;
+  late int index;
+  late TextButton previousButton;
+  late TextButton nextButton;
+  late bool previousButtonEnable;
+  late bool nextButtonEnable;
 
-  String productDesc;
-  double productPrice;
+  late String productDesc;
+  late double productPrice;
 
-  String nextText;
-  String finishText;
+  late String nextText;
+  late String finishText;
 
   Map<String, dynamic> selections = new Map();
 
@@ -118,31 +118,31 @@ class MobileAttributeSelectionState extends State<MobileAttributeSelection> {
         extendDescription.add(key + ': ' + opt.join(', '));
       });
 
-      ProductAttribute pa = product.productAttributes[index];
+      ProductAttribute pa = product.productAttributes![index];
       if (pa.required && Utils.selectionsNotEmptyAt(selections, pa.name)) {
         setState(() {
           nextButtonEnable = true;
-          productDesc = product.description + ', ' + extendDescription.join('; ');
-          productPrice = product.price + extendPrice;
+          productDesc = product.description! + ', ' + extendDescription.join('; ');
+          productPrice = product.price! + extendPrice;
         });
       } else if (!pa.required){
         setState(() {
           nextButtonEnable = true;
-          productDesc = product.description + ', ' + extendDescription.join('; ');
-          productPrice = product.price + extendPrice;
+          productDesc = product.description! + ', ' + extendDescription.join('; ');
+          productPrice = product.price! + extendPrice;
         });
       } else {
         setState(() {
           nextButtonEnable = false;
-          productDesc = product.description + ', ' + extendDescription.join('; ');
-          productPrice = product.price + extendPrice;
+          productDesc = product.description! + ', ' + extendDescription.join('; ');
+          productPrice = product.price! + extendPrice;
         });
       }
     });
   }
 
   bool _checkCanGoNext() {
-    ProductAttribute pa = product.productAttributes[index];
+    ProductAttribute pa = product.productAttributes![index];
     if (pa.required && Utils.selectionsNotEmptyAt(selections, pa.name)) {
       return true;
     } else if (!pa.required){
@@ -167,7 +167,7 @@ class MobileAttributeSelectionState extends State<MobileAttributeSelection> {
     nextButton = TextButton(
       onPressed: nextButtonEnable ? _goNext : null,
       child: new Text(
-          product.productAttributes.length > index + 1 ? nextText : finishText
+          product.productAttributes!.length > index + 1 ? nextText : finishText
       ),
     );
 
@@ -239,7 +239,7 @@ class MobileAttributeSelectionState extends State<MobileAttributeSelection> {
   Widget _getOptionsView() {
     Widget optionsView;
 
-    ProductAttribute productAttribute = product.productAttributes[index];
+    ProductAttribute productAttribute = product.productAttributes![index];
     if (productAttribute.byQuantity) {
       optionsView = new QtyOptions(product: product, index: index, selections: selections);
     } else {
@@ -254,13 +254,13 @@ class MobileAttributeSelectionState extends State<MobileAttributeSelection> {
   }
 
   void _goNext() {
-    if (index + 1 < product.productAttributes.length) {
+    if (index + 1 < product.productAttributes!.length) {
       setState(() {
         index = index + 1;
         previousButtonEnable = index >= 1;
         nextButtonEnable = _checkCanGoNext();
       });
-    } else if (product.productAttributes.length == index + 1) {
+    } else if (product.productAttributes!.length == index + 1) {
       eventBus.fire(new OnProductWillAddToCart(product, selections, productPrice, productDesc, widget.business, buttonKey: widget.startKey));
       Navigator.pop(context);
     }

lib/widgets/mobile/mobile_blog.dart

@@ -28,7 +28,7 @@ class MobileBlog extends StatefulWidget {
 }
 
 class MobileBlogState extends State<MobileBlog> {
-  List<Blog> blogs;
+  late List<Blog> blogs;
 
   int _page = 1;
   int _pageCount = 1;

lib/widgets/mobile/mobile_buy_service.dart

@@ -20,7 +20,7 @@ class MobileBuyService extends StatefulWidget {
 
 class MobileBuyServiceState extends State<MobileBuyService> {
   List<KeyValue> plans = [];
-  KeyValue selectedPlan;
+  late KeyValue selectedPlan;
   double price = 0.0;
   double tax = 0.0;
   double paymentAmount = 0.0;

lib/widgets/mobile/mobile_change_mobile_or_email.dart

@@ -31,9 +31,9 @@ class MobileChangeMobileOrEmailState extends State<MobileChangeMobileOrEmail> {
   bool usernameEnable = true;
   final codeController = TextEditingController();
 
-  bool enableGetCode;
-  String getCodeText;
-  bool canRegister;
+  late bool enableGetCode;
+  late String getCodeText;
+  late bool canRegister;
 
   var countDownListener;
 
@@ -94,7 +94,7 @@ class MobileChangeMobileOrEmailState extends State<MobileChangeMobileOrEmail> {
                     ),
                     autofocus: true,
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         if (widget.isMobile) {
                           return S
                               .of(context)
@@ -105,10 +105,10 @@ class MobileChangeMobileOrEmailState extends State<MobileChangeMobileOrEmail> {
                               .email_is_required;
                         }
                       }
-                      if (widget.isMobile && value.trim() == store.state.user.mobile) {
+                      if (widget.isMobile && value!.trim() == store.state.user!.mobile) {
                         return S.of(context).the_mobile_number_is_same_as_current;
                       }
-                      if (!widget.isMobile && value.trim() == store.state.user.email) {
+                      if (!widget.isMobile && value!.trim() == store.state.user!.email) {
                         return S.of(context).the_email_is_same_as_current;
                       }
                       return null;
@@ -191,7 +191,7 @@ class MobileChangeMobileOrEmailState extends State<MobileChangeMobileOrEmail> {
                         fontSize: 18.0
                     ),
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         return S.of(context).verification_code_is_required;
                       }
                       return null;
@@ -269,7 +269,7 @@ class MobileChangeMobileOrEmailState extends State<MobileChangeMobileOrEmail> {
         },
         isFormData: true,
         body: {
-          'id': store.state.user.id,
+          'id': store.state.user!.id,
           'mobile': usernameController.text.trim(),
           'code': codeController.text.trim(),
         },
@@ -281,8 +281,8 @@ class MobileChangeMobileOrEmailState extends State<MobileChangeMobileOrEmail> {
 
   void getCodeTapped() {
     if (usernameController.text.isNotEmpty &&
-        ((widget.isMobile && usernameController.text.trim() != store.state.user.mobile) ||
-            (!widget.isMobile && usernameController.text.trim() != store.state.user.email))) {
+        ((widget.isMobile && usernameController.text.trim() != store.state.user!.mobile) ||
+            (!widget.isMobile && usernameController.text.trim() != store.state.user!.email))) {
       HttpUtil.httpPost('v1/users', (response) {
         Fluttertoast.showToast(
             msg: S.of(context).verification_code_sent,
@@ -303,7 +303,7 @@ class MobileChangeMobileOrEmailState extends State<MobileChangeMobileOrEmail> {
           'action': 'change_mobile_email_send_code'
         },
         body: {
-          'id': store.state.user.id,
+          'id': store.state.user!.id,
           'mobile': usernameController.text,
         },
         isFormData: true,
@@ -321,9 +321,9 @@ class MobileChangeMobileOrEmailState extends State<MobileChangeMobileOrEmail> {
         errorMsg = S.of(context).mobile_is_required;
       } else if (!widget.isMobile && usernameController.text.trim().isEmpty) {
         errorMsg = S.of(context).email_is_required;
-      } else if (widget.isMobile && usernameController.text.trim() == store.state.user.mobile) {
+      } else if (widget.isMobile && usernameController.text.trim() == store.state.user!.mobile) {
         errorMsg = S.of(context).the_mobile_number_is_same_as_current;
-      } else if (!widget.isMobile && usernameController.text.trim() == store.state.user.email) {
+      } else if (!widget.isMobile && usernameController.text.trim() == store.state.user!.email) {
         errorMsg = S.of(context).the_email_is_same_as_current;
       }
       Fluttertoast.showToast(

lib/widgets/mobile/mobile_change_password.dart

@@ -22,10 +22,10 @@ class MobileChangePasswordState extends State<MobileChangePassword> {
   final passwordController = TextEditingController();
   final passwordAgainController = TextEditingController();
 
-  bool passwordVisible;
-  bool passwordAgainVisible;
+  late bool passwordVisible;
+  late bool passwordAgainVisible;
 
-  bool canReset;
+  late bool canReset;
 
   @override
   void initState() {
@@ -88,7 +88,7 @@ class MobileChangePasswordState extends State<MobileChangePassword> {
                         fontSize: 18.0
                     ),
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         return S.of(context).current_password_is_required;
                       }
                       return null;
@@ -142,7 +142,7 @@ class MobileChangePasswordState extends State<MobileChangePassword> {
                         fontSize: 18.0
                     ),
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         return S.of(context).password_is_required;
                       }
                       return null;
@@ -196,10 +196,10 @@ class MobileChangePasswordState extends State<MobileChangePassword> {
                         fontSize: 18.0
                     ),
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         return S.of(context).password_is_required;
                       }
-                      if (value.trim() != passwordController.text.trim()) {
+                      if (value!.trim() != passwordController.text.trim()) {
                         return S.of(context).password_is_not_match_password_again;
                       }
                       return null;
@@ -276,7 +276,7 @@ class MobileChangePasswordState extends State<MobileChangePassword> {
           },
           isFormData: true,
           body: {
-            'id': store.state.user.id,
+            'id': store.state.user!.id,
             'old_password': oldPasswordController.text.trim(),
             'password': passwordController.text.trim(),
           }

lib/widgets/mobile/mobile_checkout.dart

@@ -45,17 +45,17 @@ class MobileCheckout extends StatefulWidget {
 }
 
 class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProviderStateMixin, AutomaticKeepAliveClientMixin {
-  CartInfo cartInfo;
-  Address shipAddress;
-  bool canSubmit;
-  List<ErrorMessage> errorMessages;
-  List<BookingTime> bookingTimeList;
-  List<BookingDateTime> bookingDateTimeList;
-  List<PaymentPlatform> paymentPlatforms;
-  TextValue durationInTraffic;
-  int selectedCoupon;
+  late CartInfo cartInfo;
+  late Address shipAddress;
+  late bool canSubmit;
+  late List<ErrorMessage> errorMessages;
+  late List<BookingTime> bookingTimeList;
+  late List<BookingDateTime> bookingDateTimeList;
+  late List<PaymentPlatform> paymentPlatforms;
+  late TextValue durationInTraffic;
+  late int selectedCoupon;
   double couponDiscountAmount = 0;
-  List<Coupon> coupons;
+  late List<Coupon> coupons;
 
   int peopleCount = 2;
 
@@ -63,25 +63,25 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
   String orderRemark = '';
 
   int deliveryMethodIndex = 0;
-  String deliveryMethod;
+  late String deliveryMethod;
   List<ShippingRate> shippingRates = [];
-  ShippingRate selectedShippingRate;
+  late ShippingRate selectedShippingRate;
 
   List<String> shippingMethodLabels = [];
   List<IconData> shippingMethodIcons = [];
 
   GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();
 
-  int bookingDateIndex;
-  int bookingTimeIndex;
-  int paymentPlatformIndex;
+  late int bookingDateIndex;
+  late int bookingTimeIndex;
+  late int paymentPlatformIndex;
 
   GlobalKey slidingUpPanelKey = GlobalKey();
-  SlidingUpPanel slidingUpPanel;
+  late SlidingUpPanel slidingUpPanel;
   PanelController panelController = PanelController();
-  Widget panel;
+  late Widget panel;
 
-  double subtotal;
+  late double subtotal;
 
   TextEditingController newCouponController = TextEditingController();
 
@@ -102,7 +102,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
       );
     }
 
-    if (cartInfo.businessInfo.deliveryPickup == false && cartInfo.businessInfo.deliveryCanadaPost == false && cartInfo.businessInfo.deliveryStoreDelivery == false) {
+    if (cartInfo.businessInfo!.deliveryPickup == false && cartInfo.businessInfo!.deliveryCanadaPost == false && cartInfo.businessInfo!.deliveryStoreDelivery == false) {
       return Scaffold(
         body: Container(
           child: Center(
@@ -197,13 +197,13 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
                   mainAxisAlignment: MainAxisAlignment.spaceBetween,
                   children: [
                     Text(
-                      '\$${(cartInfo.totalPrice - couponDiscountAmount).toStringAsFixed(2)}',
+                      '\$${(cartInfo.totalPrice! - couponDiscountAmount).toStringAsFixed(2)}',
                       style: TextStyle(
                         fontSize: 20.0,
                         color: Colors.white,
                       ),
                     ),
-                    cartInfo.businessInfo.isPublic ? SizedBox.shrink() : Container(
+                    cartInfo.businessInfo!.isPublic ? SizedBox.shrink() : Container(
                       padding: EdgeInsets.only(top: 2.0, bottom: 2.0, left: 5.0, right: 5.0),
                       width: 100.0,
                       color: Colors.red,
@@ -267,7 +267,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
       itemCount: 6,
       addAutomaticKeepAlives: true,
       itemBuilder: (BuildContext context, int position) {
-        var deliveryTimeInSeconds = cartInfo.businessInfo.shippingTime * 60 + (durationInTraffic != null ? durationInTraffic.value : 0);
+        var deliveryTimeInSeconds = cartInfo.businessInfo!.shippingTime! * 60 + (durationInTraffic != null ? durationInTraffic.value : 0);
         print('aaa: $deliveryTimeInSeconds');
         DateTime now = DateTime.now();
         var formatter = DateFormat('H:mm');
@@ -341,7 +341,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
         );
         switch (position) {
           case 0:
-            if (cartInfo.businessInfo.deliveryPickup) {
+            if (cartInfo.businessInfo!.deliveryPickup) {
               return Container(
                 padding: EdgeInsets.only(
                     top: 16.0, bottom: 16.0, left: 16.0, right: 16.0),
@@ -355,8 +355,8 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
                 ),
                 child: Container(
                   alignment: Alignment.centerLeft,
-                  child: store.state.deviceId != null && store.state.deviceId.isNotEmpty ? (
-                      store.state.tableNumber != null && store.state.tableNumber.isNotEmpty ?
+                  child: store.state.deviceId != null && store.state.deviceId!.isNotEmpty ? (
+                      store.state.tableNumber != null && store.state.tableNumber!.isNotEmpty ?
                       peopleCountSelection :
                       SizedBox.shrink()
                   ) : Center(child: toggleSwitch,),
@@ -369,8 +369,8 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
             }
             break;
           case 1:
-            if (store.state.deviceId != null && store.state.deviceId.isNotEmpty ||
-                store.state.tableNumber != null && store.state.tableNumber.isNotEmpty) {
+            if (store.state.deviceId != null && store.state.deviceId!.isNotEmpty ||
+                store.state.tableNumber != null && store.state.tableNumber!.isNotEmpty) {
               return SizedBox.shrink();
             }
             if (deliveryMethod == 'pickup') {
@@ -389,7 +389,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
                     Container(
                       margin: EdgeInsets.only(top: 10.0),
                       child: Text(
-                        cartInfo.businessInfo.name,
+                        cartInfo.businessInfo!.name,
                         style: TextStyle(
                           fontSize: 17.0,
                         ),
@@ -398,7 +398,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
                     Container(
                       margin: EdgeInsets.only(top: 5.0),
                       child: Text(
-                        cartInfo.businessInfo.address.addressLine1,
+                        cartInfo.businessInfo!.address!.addressLine1,
                         style: TextStyle(
                           fontSize: 14.0,
                           color: Colors.black45,
@@ -406,9 +406,9 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
                       ),
                     ),
                     Container(
-                      child: cartInfo.businessInfo.address.addressLine2 != null
-                          && cartInfo.businessInfo.address.addressLine2.length > 0 ?
-                      Text(cartInfo.businessInfo.address.addressLine2,
+                      child: cartInfo.businessInfo!.address!.addressLine2 != null
+                          && cartInfo.businessInfo!.address!.addressLine2!.length > 0 ?
+                      Text(cartInfo.businessInfo!.address!.addressLine2,
                         style: TextStyle(
                           fontSize: 14.0,
                           color: Colors.black45,
@@ -417,7 +417,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
                     ),
                     Container(
                       child: Text(
-                        '${cartInfo.businessInfo.address.city}, ${cartInfo.businessInfo.address.state}, ${cartInfo.businessInfo.address.zip}',
+                        '${cartInfo.businessInfo!.address!.city}, ${cartInfo.businessInfo!.address!.state}, ${cartInfo.businessInfo!.address!.zip}',
                         style: TextStyle(
                           fontSize: 14.0,
                           color: Colors.black45,
@@ -427,7 +427,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
                     Container(
                       margin: EdgeInsets.only(top: 5.0),
                       child: Text(
-                        'Tel: ${cartInfo.businessInfo.phone}',
+                        'Tel: ${cartInfo.businessInfo!.phone}',
                         style: TextStyle(
                           fontSize: 15.0,
                           color: Colors.black54,
@@ -480,7 +480,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
                             Container(
                               padding: EdgeInsets.only(top: 6.0),
                               child: Text(
-                                shipAddress != null ? shipAddress.contactName + ' ' + shipAddress.phone : '',
+                                shipAddress != null ? shipAddress.contactName! + ' ' + shipAddress.phone : '',
                                 style: TextStyle(
                                   fontSize: 14.0,
                                   color: Colors.black38,
@@ -504,13 +504,13 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
                 ),
               ),
               onTap: () {
-                Routes.router.navigateTo(context, '/my-addresses/${cartInfo.businessInfo.id}', replace: true);
+                Routes.router.navigateTo(context, '/my-addresses/${cartInfo.businessInfo!.id}', replace: true);
               },
             );
             break;
           case 2:
-            if (deliveryMethod == 'pickup' || store.state.deviceId != null && store.state.deviceId.isNotEmpty ||
-                store.state.tableNumber != null && store.state.tableNumber.isNotEmpty) {
+            if (deliveryMethod == 'pickup' || store.state.deviceId != null && store.state.deviceId!.isNotEmpty ||
+                store.state.tableNumber != null && store.state.tableNumber!.isNotEmpty) {
               return SizedBox.shrink();
             }
             if (deliveryMethod == 'canada-post') {
@@ -553,7 +553,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
                                   alignment: Alignment.centerRight,
                                   child: Text(
                                       selectedShippingRate != null ?
-                                    '${selectedShippingRate.name} \$${selectedShippingRate.price.toStringAsFixed(2)}' :
+                                    '${selectedShippingRate.name} \$${selectedShippingRate.price!.toStringAsFixed(2)}' :
                                     S.of(context).please_select,
                                     style: TextStyle(
                                       fontSize: 15.0,
@@ -583,7 +583,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
                 },
               );
             }
-            if (!cartInfo.businessInfo.instanceDelivery) {
+            if (!cartInfo.businessInfo!.instanceDelivery) {
               return Container(
                 padding: EdgeInsets.only(left: 16.0, right: 16.0, top: 0.0, bottom: 16.0),
                 child: Text(S.of(context).no_instance_delivery_desc),
@@ -629,7 +629,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
                             child: Text(
                               bookingTimeList.length > 0 ? '${Utils.timestampToString(context, bookingTimeList[bookingTimeIndex].unixTime)}'
                                   : ((bookingTimeList.length == 0 && bookingDateTimeList.length == 0) ? ''
-                                  : bookingDateTimeList[bookingDateIndex].viewDate + ' ' + (bookingDateTimeList[bookingDateIndex].bookTimes.length > 0 ? bookingDateTimeList[bookingDateIndex].bookTimes[bookingTimeIndex].viewTime : '')),
+                                  : bookingDateTimeList[bookingDateIndex].viewDate! + ' ' + (bookingDateTimeList[bookingDateIndex].bookTimes!.length > 0 ? bookingDateTimeList[bookingDateIndex].bookTimes![bookingTimeIndex].viewTime : '')),
                             ),
                           ),
                           Container(
@@ -712,7 +712,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
               width: double.infinity,
               padding: EdgeInsets.only(bottom: 10.0),
               child: Text(
-                cartInfo.businessInfo.name,
+                cartInfo.businessInfo!.name,
                 overflow: TextOverflow.ellipsis,
                 style: TextStyle(
                   fontSize: 16.0,
@@ -731,9 +731,9 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
 
             subtotal = 0.0;
 
-            for (var i = 0; i < cartInfo.productList.length; i++) {
-              subtotal += cartInfo.productList[i].totalPrice;
-              column.children.add(lineItem(cartInfo.productList[i]));
+            for (var i = 0; i < cartInfo.productList!.length; i++) {
+              subtotal += cartInfo.productList![i].totalPrice;
+              column.children.add(lineItem(cartInfo.productList![i]));
             }
             column.children.add(GestureDetector(
               child: Container(
@@ -826,8 +826,8 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
               ),
             ));
 
-            if (cartInfo.extraFeeList.length > 0) {
-              for (var i = 0; i < cartInfo.extraFeeList.length; i++) {
+            if (cartInfo.extraFeeList!.length > 0) {
+              for (var i = 0; i < cartInfo.extraFeeList!.length; i++) {
                 column.children.add(Container(
                   padding: EdgeInsets.only(bottom: 16.0),
                   alignment: Alignment.centerRight,
@@ -838,7 +838,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
                       Container(
                         alignment: Alignment.centerRight,
                         child: Text(
-                          S.of(context).extra_fee_token(cartInfo.extraFeeList[i].name, cartInfo.extraFeeList[i].rate),
+                          S.of(context).extra_fee_token(cartInfo.extraFeeList![i].name, cartInfo.extraFeeList![i].rate),
                           style: TextStyle(
                             color: Colors.grey,
                           ),
@@ -848,7 +848,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
                         width: 100.0,
                         alignment: Alignment.centerRight,
                         child: Text(
-                            '${cartInfo.extraFeeList[i].price.toStringAsFixed(2)}'
+                            '${cartInfo.extraFeeList![i].price!.toStringAsFixed(2)}'
                         ),
                       ),
                     ],
@@ -876,7 +876,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
                     width: 100.0,
                     alignment: Alignment.centerRight,
                     child: Text(
-                      '${(cartInfo.totalPrice - couponDiscountAmount).toStringAsFixed(2)}',
+                      '${(cartInfo.totalPrice! - couponDiscountAmount).toStringAsFixed(2)}',
                       style: TextStyle(
                         fontSize: 19.0,
                         fontWeight: FontWeight.bold,
@@ -974,7 +974,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
         children: <Widget>[
           Container(
             padding: EdgeInsets.all(5.0),
-            child: Util.showImage('${cartLineItem.product.imagePath}',
+            child: Util.showImage('${cartLineItem.product!.imagePath}',
               width: 40.0,
               height: 40.0,
               fit: BoxFit.fill,
@@ -1011,14 +1011,14 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
             alignment: Alignment.centerRight,
             margin: EdgeInsets.only(right: 10.0),
             child: Text(
-              'x${cartLineItem.quantity.round()}',
+              'x${cartLineItem.quantity!.round()}',
             ),
           ),
           Container(
             width: 60.0,
             alignment: Alignment.centerRight,
             child: Text(
-              '${cartLineItem.totalPrice.toStringAsFixed(2)}',
+              '${cartLineItem.totalPrice!.toStringAsFixed(2)}',
             ),
           ),
         ],
@@ -1074,7 +1074,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
           shippingRates = (response.data['shipping_rates'] as List).map((e) => ShippingRate.fromJson(e)).toList();
           selectedShippingRate = (response.data['selected_shipping_rate'] as String).length > 0 ? ShippingRate.fromJson(json.decode(response.data['selected_shipping_rate'])) : null;
           int i = 0;
-          if (cartInfo.businessInfo.deliveryStoreDelivery) {
+          if (cartInfo.businessInfo!.deliveryStoreDelivery) {
             shippingMethodLabels.add(S.of(context).delivery);
             shippingMethodIcons.add(Icons.directions_car);
             if (deliveryMethod == 'store-delivery') {
@@ -1082,7 +1082,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
             }
             i++;
           }
-          if (cartInfo.businessInfo.deliveryCanadaPost) {
+          if (cartInfo.businessInfo!.deliveryCanadaPost) {
             shippingMethodLabels.add(S.of(context).canada_post);
             shippingMethodIcons.add(Icons.local_shipping);
             if (deliveryMethod == 'canada-post') {
@@ -1090,7 +1090,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
             }
             i++;
           }
-          if (cartInfo.businessInfo.deliveryPickup) {
+          if (cartInfo.businessInfo!.deliveryPickup) {
             shippingMethodLabels.add(S.of(context).pickup);
             shippingMethodIcons.add(Icons.store);
             if (deliveryMethod == 'pickup') {
@@ -1310,14 +1310,14 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
                 Expanded(
                   child: SizedBox.expand(
                     child: ListView.builder(
-                      itemCount: bookingDateTimeList[bookingDateIndex].bookTimes.length,
+                      itemCount: bookingDateTimeList[bookingDateIndex].bookTimes!.length,
                       itemBuilder: (BuildContext context, int position) {
                         BookingDateTime bookingDateTime = bookingDateTimeList[bookingDateIndex];
                         return GestureDetector(
                           child: Container(
                             padding: EdgeInsets.only(left: 12.0, right: 12.0, top: 12.0, bottom: 12.0),
                             child: Text(
-                              bookingDateTime.bookTimes[position].viewTime,
+                              bookingDateTime.bookTimes![position].viewTime,
                             ),
                             decoration: BoxDecoration(
                               border: Border(
@@ -1442,16 +1442,16 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
             itemBuilder: (BuildContext context, int position) {
               PaymentPlatform paymentPlatform = paymentPlatforms[position];
               if (paymentPlatform.code == Constants.PAYMENT_METHOD_CODE_SQUARE &&
-                  (paymentPlatform.squareAppId == null || paymentPlatform.squareAppId.isEmpty) &&
-                  (paymentPlatform.squareAccessToken == null || paymentPlatform.squareAccessToken.isEmpty) &&
-                  (paymentPlatform.squareLocationId == null || paymentPlatform.squareLocationId.isEmpty)
+                  (paymentPlatform.squareAppId == null || paymentPlatform.squareAppId!.isEmpty) &&
+                  (paymentPlatform.squareAccessToken == null || paymentPlatform.squareAccessToken!.isEmpty) &&
+                  (paymentPlatform.squareLocationId == null || paymentPlatform.squareLocationId!.isEmpty)
               ) {
                 return SizedBox.shrink();
               }
               if (paymentPlatform.code == Constants.PAYMENT_METHOD_CODE_CHASE &&
-                  (paymentPlatform.xLogin == null || paymentPlatform.xLogin.isEmpty) &&
-                  (paymentPlatform.transactionKey == null || paymentPlatform.transactionKey.isEmpty) &&
-                  (paymentPlatform.responseKey == null || paymentPlatform.responseKey.isEmpty)
+                  (paymentPlatform.xLogin == null || paymentPlatform.xLogin!.isEmpty) &&
+                  (paymentPlatform.transactionKey == null || paymentPlatform.transactionKey!.isEmpty) &&
+                  (paymentPlatform.responseKey == null || paymentPlatform.responseKey!.isEmpty)
               ) {
                 return SizedBox.shrink();
               }
@@ -1681,7 +1681,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
               return GestureDetector(
                 child: Container(
                   decoration: selectedCoupon == 0 ? BoxDecoration(
-                    color: subtotal > cartInfo.businessInfo.minPrice ? Colors
+                    color: subtotal > cartInfo.businessInfo!.minPrice ? Colors
                         .transparent : Colors.black38,
                     border: Border(
                       top: BorderSide(
@@ -1702,7 +1702,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
                       ),
                     ),
                   ) : BoxDecoration(
-                    color: subtotal > cartInfo.businessInfo.minPrice ? Colors
+                    color: subtotal > cartInfo.businessInfo!.minPrice ? Colors
                         .transparent : Colors.black38,
                   ),
                   child: Row(
@@ -1743,7 +1743,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
               return GestureDetector(
                 child: Container(
                   decoration: selectedCoupon == coupon.id ? BoxDecoration(
-                    color: subtotal > cartInfo.businessInfo.minPrice ? Colors
+                    color: subtotal > cartInfo.businessInfo!.minPrice ? Colors
                         .transparent : Colors.black38,
                     border: Border(
                       top: BorderSide(
@@ -1857,7 +1857,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
                               ),
                               Container(
                                 child: Text(
-                                  coupon.minAmount > 0 ?
+                                  coupon.minAmount! > 0 ?
                                   S.of(context).min_order_amount_token(
                                       coupon.minAmount) :
                                   S.of(context)
@@ -1917,7 +1917,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
       crossAxisAlignment: CrossAxisAlignment.start,
       children: [],
     );
-    if (cartInfo.businessInfo.quickInputs.length > 0) {
+    if (cartInfo.businessInfo!.quickInputs!.length > 0) {
       Wrap w = Wrap(
         children: [],
       );
@@ -1931,8 +1931,8 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
           ),
         ),
       ));
-      for (int i = 0; i < cartInfo.businessInfo.quickInputs.length; i++) {
-        String qi = cartInfo.businessInfo.quickInputs[i].value;
+      for (int i = 0; i < cartInfo.businessInfo!.quickInputs!.length; i++) {
+        String qi = cartInfo.businessInfo!.quickInputs![i].value;
         w.children.add(TextButton(
           child: Text(
             qi,
@@ -2112,7 +2112,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
                     child: Container(
                       alignment: Alignment.centerRight,
                       child: Text(
-                        '${shippingRate.price.toStringAsFixed(2)}',
+                        '${shippingRate.price!.toStringAsFixed(2)}',
                         style: TextStyle(
                           fontSize: 16.0,
                           color: Colors.black38,
@@ -2203,7 +2203,7 @@ class MobileCheckoutState extends State<MobileCheckout> with SingleTickerProvide
               : (
               (bookingTimeList.length == 0 && bookingDateTimeList.length == 0) ?
               0 :
-              bookingDateTimeList[bookingDateIndex].bookTimes[bookingTimeIndex]
+              bookingDateTimeList[bookingDateIndex].bookTimes![bookingTimeIndex]
                   .unixTime
           ),
           'delivery': deliveryMethod,

lib/widgets/mobile/mobile_contact_us.dart

@@ -29,7 +29,7 @@ class MobileContactUsState extends State<MobileContactUs> {
   String mapUrl = 'https://goo.gl/maps/M365MF5AW35n9ij67';
 
   Completer<GoogleMapController> _controller = Completer();
-  LatLng _lastMapPosition;
+  late LatLng _lastMapPosition;
   final Set<Marker> _markers = {};
   final Set<Polyline> _polyLine = {};
 
@@ -239,16 +239,16 @@ class MobileContactUsState extends State<MobileContactUs> {
         Container(
           padding: EdgeInsets.only(left: 16, right: 16, top: 4, bottom: 4),
           child: Text(
-            '${widget.business.address.addressLine1}',
+            '${widget.business.address!.addressLine1}',
           ),
         )
     );
-    if (widget.business.address.addressLine2 != null && widget.business.address.addressLine2.isNotEmpty) {
+    if (widget.business.address!.addressLine2 != null && widget.business.address!.addressLine2!.isNotEmpty) {
       col.children.add(
           Container(
             padding: EdgeInsets.only(left: 16, right: 16, top: 4, bottom: 4),
             child: Text(
-              '${widget.business.address.addressLine2}',
+              '${widget.business.address!.addressLine2}',
             ),
           )
       );
@@ -257,7 +257,7 @@ class MobileContactUsState extends State<MobileContactUs> {
         Container(
           padding: EdgeInsets.only(left: 16, right: 16, top: 4, bottom: 4),
           child: Text(
-            '${widget.business.address.city}, ${widget.business.address.state}',
+            '${widget.business.address!.city}, ${widget.business.address!.state}',
           ),
         )
     );
@@ -265,7 +265,7 @@ class MobileContactUsState extends State<MobileContactUs> {
         Container(
           padding: EdgeInsets.only(left: 16, right: 16, top: 4, bottom: 4),
           child: Text(
-            '${widget.business.address.country}, ${widget.business.address.zip}',
+            '${widget.business.address!.country}, ${widget.business.address!.zip}',
           ),
         )
     );
@@ -273,8 +273,8 @@ class MobileContactUsState extends State<MobileContactUs> {
       _markers.clear();
       _markers.add(Marker(
         markerId: MarkerId('shop_position'),
-        position: LatLng(double.parse(widget.business.address.lat),
-            double.parse(widget.business.address.lng)),
+        position: LatLng(double.parse(widget.business.address!.lat),
+            double.parse(widget.business.address!.lng)),
         infoWindow: InfoWindow(
           title: S
               .of(context)
@@ -290,8 +290,8 @@ class MobileContactUsState extends State<MobileContactUs> {
             onMapCreated: _onMapCreated,
             initialCameraPosition: CameraPosition(
               target: LatLng(
-                  double.parse(widget.business.address.lat),
-                  double.parse(widget.business.address.lng)),
+                  double.parse(widget.business.address!.lat),
+                  double.parse(widget.business.address!.lng)),
               zoom: 14.0,
             ),
             onCameraMove: _onCameraMove,

lib/widgets/mobile/mobile_coupons.dart

@@ -24,7 +24,7 @@ class MobileCoupons extends StatefulWidget {
 }
 
 class MobileCouponsState extends State<MobileCoupons> {
-  List<Coupon> coupons;
+  late List<Coupon> coupons;
 
   @override
   Widget build(BuildContext context) {
@@ -97,7 +97,7 @@ class MobileCouponsState extends State<MobileCoupons> {
                 Container(
                   padding: EdgeInsets.only(right: 5.0),
                   child: coupon.store != null ?
-                  Util.showImage('${coupon.store.picUrl}',
+                  Util.showImage('${coupon.store!.picUrl}',
                     fit: BoxFit.fill,
                     width: 40.0,
                   ) :
@@ -114,7 +114,7 @@ class MobileCouponsState extends State<MobileCoupons> {
                     crossAxisAlignment: CrossAxisAlignment.start,
                     children: <Widget>[
                       Text(
-                        coupon.store != null ? coupon.store.name : S.of(context).general_coupon,
+                        coupon.store != null ? coupon.store!.name : S.of(context).general_coupon,
                         style: TextStyle(
                           fontSize: 20.0,
                           fontWeight: FontWeight.bold,
@@ -198,7 +198,7 @@ class MobileCouponsState extends State<MobileCoupons> {
         ),
         Container(
           child: Text(
-            coupon.minAmount > 0 ?
+            coupon.minAmount! > 0 ?
             S.of(context).available_for_order_over_token(coupon.minAmount) :
             S.of(context).no_restriction,
             style: TextStyle(
@@ -236,7 +236,7 @@ class MobileCouponsState extends State<MobileCoupons> {
         children: <Widget>[
           Container(
             child: Text(
-              coupon.expirationDate == null || coupon.expirationDate.length == 0 ?
+              coupon.expirationDate == null || coupon.expirationDate!.length == 0 ?
                   S.of(context).no_expiration :
                   S.of(context).expiration_date_token(coupon.expirationDate),
               style: TextStyle(
@@ -261,7 +261,7 @@ class MobileCouponsState extends State<MobileCoupons> {
               ),
               onPressed: () {
                 if (coupon.store != null) {
-                  Routes.router.navigateTo(context, '/shop/${coupon.store.id}/na/na/na');
+                  Routes.router.navigateTo(context, '/shop/${coupon.store!.id}/na/na/na');
                 } else {
                   Routes.router.navigateTo(context, '/businesses');
                 }

lib/widgets/mobile/mobile_edit_address.dart

@@ -43,12 +43,12 @@ class MobileEditAddressState extends State<MobileEditAddress> {
   final emailController = TextEditingController();
   final faxController = TextEditingController();
 
-  String country;
-  Gender _selectedGender;
+  late String country;
+  late Gender _selectedGender;
 
-  String _selectedProvince;
+  late String _selectedProvince;
 
-  bool showLoading;
+  late bool showLoading;
 
   @override
   Widget build(BuildContext context) {
@@ -366,7 +366,7 @@ class MobileEditAddressState extends State<MobileEditAddress> {
                         .email,
                   ),
                   validator: (String? value) {
-                    if (value.isNotEmpty && !EmailValidator.validate(value)) {
+                    if (value!.isNotEmpty && !EmailValidator.validate(value)) {
                       return S
                           .of(context)
                           .email_is_not_valid;

lib/widgets/mobile/mobile_forgot_password.dart

@@ -28,9 +28,9 @@ class MobileForgotPasswordState extends State<MobileForgotPassword> {
   bool usernameEnable = true;
   final codeController = TextEditingController();
 
-  bool enableGetCode;
-  String getCodeText;
-  bool canRegister;
+  late bool enableGetCode;
+  late String getCodeText;
+  late bool canRegister;
 
   var countDownListener;
 
@@ -91,7 +91,7 @@ class MobileForgotPasswordState extends State<MobileForgotPassword> {
                     ),
                     autofocus: true,
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         return S.of(context).mobile_or_email_is_required;
                       }
                       return null;
@@ -174,7 +174,7 @@ class MobileForgotPasswordState extends State<MobileForgotPassword> {
                         fontSize: 18.0
                     ),
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         return S.of(context).verification_code_is_required;
                       }
                       return null;

lib/widgets/mobile/mobile_login.dart

@@ -26,9 +26,9 @@ class MobileLoginState extends State<MobileLogin> {
 
   final usernameController = TextEditingController();
   final passwordController = TextEditingController();
-  bool passwordVisible;
+  late bool passwordVisible;
 
-  bool onSubmitting;
+  late bool onSubmitting;
 
   @override
   void initState() {
@@ -104,7 +104,7 @@ class MobileLoginState extends State<MobileLogin> {
                   ),
                   autofocus: true,
                   validator: (String? value) {
-                    if (value.trim().isEmpty) {
+                    if (value!.trim().isEmpty) {
                       return S.of(context).this_field_is_required;
                     }
                     return null;
@@ -144,7 +144,7 @@ class MobileLoginState extends State<MobileLogin> {
                   ),
                   obscureText: passwordVisible,
                   validator: (String? value) {
-                    if (value.trim().isEmpty) {
+                    if (value!.trim().isEmpty) {
                       return S.of(context).password_is_required;
                     }
                     return null;

lib/widgets/mobile/mobile_me.dart

@@ -20,9 +20,9 @@ import '../../utils/util_web.dart'
     if (dart.library.io) '../../utils/util_io.dart';
 import '../../utils/utils.dart';
 
-MediaQueryData mediaQuery;
-double statusBarHeight;
-double screenHeight;
+late MediaQueryData mediaQuery;
+late double statusBarHeight;
+late double screenHeight;
 
 class MobileMe extends StatefulWidget {
   final Key? key;
@@ -36,18 +36,18 @@ class MobileMe extends StatefulWidget {
 }
 
 class MobileMeState extends State<MobileMe> {
-  int userId;
-  String accessToken;
+  late int userId;
+  late String accessToken;
 
-  bool isLoading;
-  User _user;
+  late bool isLoading;
+  late User _user;
 
-  ShopScrollCoordinator _shopCoordinator;
-  ShopScrollController _pageScrollController;
+  late ShopScrollCoordinator _shopCoordinator;
+  late ShopScrollController _pageScrollController;
   final double _sliverAppBarInitHeight = 165.0;
   final double _appBarHeight = 85.0;
 
-  ShopScrollController _listScrollController1;
+  late ShopScrollController _listScrollController1;
 
   @override
   Widget build(BuildContext context) {
@@ -88,7 +88,7 @@ class MobileMeState extends State<MobileMe> {
           children: <Widget>[
             Container(
               margin: EdgeInsets.only(right: 5.0),
-              child: _user != null && _user.avatarUrl.isNotEmpty
+              child: _user != null && _user.avatarUrl!.isNotEmpty
                   ? Util.showImage(
                       'https:${_user.avatarUrl}',
                       width: 60,
@@ -219,7 +219,7 @@ class MobileMeState extends State<MobileMe> {
                             Container(
                               child: Text(
                                 _user != null
-                                    ? '${_user.wallet.toStringAsFixed(2)}'
+                                    ? '${_user.wallet!.toStringAsFixed(2)}'
                                     : '0.00',
                                 style: TextStyle(
                                   fontSize: 24.0,
@@ -671,7 +671,7 @@ class MobileMeState extends State<MobileMe> {
                       ),
                       onTap: () {
                         if (_user != null) {
-                          if (_user.email == null || _user.email.isEmpty) {
+                          if (_user.email == null || _user.email!.isEmpty) {
                             showDialog(
                                 context: context,
                                 builder: (BuildContext context) {

lib/widgets/mobile/mobile_my_addresses.dart

@@ -27,7 +27,7 @@ class MobileMyAddresses extends StatefulWidget {
 }
 
 class MobileMyAddressesState extends State<MobileMyAddresses> {
-  List<Address> addresses;
+  late List<Address> addresses;
 
   @override
   Widget build(BuildContext context) {

lib/widgets/mobile/mobile_my_support.dart

@@ -28,7 +28,7 @@ class MobileMySupport extends StatefulWidget {
 }
 
 class MobileMySupportState extends State<MobileMySupport> {
-  List<Ticket> tickets;
+  late List<Ticket> tickets;
 
   int _page = 1;
   int _pageCount = 1;
@@ -179,7 +179,7 @@ class MobileMySupportState extends State<MobileMySupport> {
                         children: <Widget>[
                           Container(
                             child: Text(
-                              ticket.issue.msg,
+                              ticket.issue!.msg,
                               style: TextStyle(
                                 fontSize: 19.0,
                               ),
@@ -208,7 +208,7 @@ class MobileMySupportState extends State<MobileMySupport> {
                                 ) :
                                 SizedBox.shrink(),
                                 Text(
-                                  S.of(context).followups_token(ticket.followUps.length),
+                                  S.of(context).followups_token(ticket.followUps!.length),
                                   style: TextStyle(
                                     fontSize: 15.0,
                                     color: Colors.black87,

lib/widgets/mobile/mobile_new_address.dart

@@ -36,9 +36,9 @@ class MobileNewAddressState extends State<MobileNewAddress> {
   final faxController = TextEditingController();
 
   String country = 'CA';
-  Gender _selectedGender;
+  late Gender _selectedGender;
 
-  String _selectedProvince;
+  late String _selectedProvince;
 
   List<String> provinces = <String>[
     'Ontario',
@@ -97,7 +97,7 @@ class MobileNewAddressState extends State<MobileNewAddress> {
                     labelText: S.of(context).contact_name,
                   ),
                   validator: (String? value) {
-                    if (value.trim().isEmpty) {
+                    if (value!.trim().isEmpty) {
                       return S.of(context).contact_name_is_required;
                     }
                     return null;
@@ -141,7 +141,7 @@ class MobileNewAddressState extends State<MobileNewAddress> {
                     labelText: S.of(context).mobile_phone_number,
                   ),
                   validator: (String? value) {
-                    if (value.trim().isEmpty) {
+                    if (value!.trim().isEmpty) {
                       return S.of(context).mobile_phone_number_is_required;
                     }
                     return null;
@@ -166,7 +166,7 @@ class MobileNewAddressState extends State<MobileNewAddress> {
                     labelText: S.of(context).street_line_1,
                   ),
                   validator: (String? value) {
-                    if (value.trim().isEmpty) {
+                    if (value!.trim().isEmpty) {
                       return S.of(context).street_line_1_is_required;
                     }
                     return null;
@@ -210,7 +210,7 @@ class MobileNewAddressState extends State<MobileNewAddress> {
                     labelText: S.of(context).city,
                   ),
                   validator: (String? value) {
-                    if (value.trim().isEmpty) {
+                    if (value!.trim().isEmpty) {
                       return S.of(context).city_is_required;
                     }
                     return null;
@@ -256,7 +256,7 @@ class MobileNewAddressState extends State<MobileNewAddress> {
                     labelText: S.of(context).postal_code,
                   ),
                   validator: (String? value) {
-                    if (value.trim().isEmpty) {
+                    if (value!.trim().isEmpty) {
                       return S.of(context).postal_code_is_required;
                     }
                     return null;
@@ -291,7 +291,7 @@ class MobileNewAddressState extends State<MobileNewAddress> {
                     labelText: S.of(context).email,
                   ),
                   validator: (String? value) {
-                    if (value.isNotEmpty && !EmailValidator.validate(value)) {
+                    if (value!.isNotEmpty && !EmailValidator.validate(value)) {
                       return S.of(context).email_is_not_valid;
                     }
                     return null;
@@ -354,8 +354,8 @@ class MobileNewAddressState extends State<MobileNewAddress> {
         cityController.text = widget.locatedAddress.city;
         postalCodeController.text = widget.locatedAddress.postalCode;
         streetLine1Controller.text = (widget.locatedAddress.streetNumber != null
-            && widget.locatedAddress.streetNumber.isNotEmpty
-            ? widget.locatedAddress.streetNumber + ' ' : '')
+            && widget.locatedAddress.streetNumber!.isNotEmpty
+            ? widget.locatedAddress.streetNumber! + ' ' : '')
             + widget.locatedAddress.streetName;
       } else {
         _selectedProvince = 'Ontario';

lib/widgets/mobile/mobile_new_comment.dart

@@ -31,13 +31,13 @@ class MobileNewComment extends StatefulWidget {
 }
 
 class MobileNewCommentState extends State<MobileNewComment> {
-  Comment comment;
+  late Comment comment;
 
-  bool _showProgress;
+  late bool _showProgress;
 
-  double _progress;
+  late double _progress;
 
-  double rating;
+  late double rating;
 
   bool isSubmitting = false;
 
@@ -167,7 +167,7 @@ class MobileNewCommentState extends State<MobileNewComment> {
       children: <Widget>[],
     );
 
-    if (comment != null && comment.images.length > 0) {
+    if (comment != null && comment.images!.length > 0) {
       for (ProductImage image in comment.images) {
         row.children.add(
           Container(
@@ -239,7 +239,7 @@ class MobileNewCommentState extends State<MobileNewComment> {
           child: Icon(
             Icons.add,
             size: 60.0,
-            color: comment == null || comment.images.length < 3 ? Colors.lightBlue : Colors.black12,
+            color: comment == null || comment.images!.length < 3 ? Colors.lightBlue : Colors.black12,
           ),
           decoration: BoxDecoration(
             color: Colors.white70,
@@ -264,7 +264,7 @@ class MobileNewCommentState extends State<MobileNewComment> {
           ),
         ),
         onTap: () {
-          if (comment == null || comment.images.length < 3) {
+          if (comment == null || comment.images!.length < 3) {
             showDialog(
                 context: mainContext,
                 barrierDismissible: true,

lib/widgets/mobile/mobile_new_ticket.dart

@@ -111,7 +111,7 @@ class MobileNewTicketState extends State<MobileNewTicket> {
                   ),
                   autofocus: true,
                   validator: (String? value) {
-                    if (value.trim().isEmpty) {
+                    if (value!.trim().isEmpty) {
                       return S.of(context).this_field_is_required;
                     }
                     return null;

lib/widgets/mobile/mobile_new_user.dart

@@ -28,9 +28,9 @@ class MobileNewUserState extends State<MobileNewUser> {
   bool usernameEnable = true;
   final codeController = TextEditingController();
 
-  bool enableGetCode;
-  String getCodeText;
-  bool canRegister;
+  late bool enableGetCode;
+  late String getCodeText;
+  late bool canRegister;
 
   var countDownListener;
 
@@ -88,7 +88,7 @@ class MobileNewUserState extends State<MobileNewUser> {
                     ),
                     autofocus: true,
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         return S.of(context).mobile_or_email_is_required;
                       }
                       return null;
@@ -171,7 +171,7 @@ class MobileNewUserState extends State<MobileNewUser> {
                         fontSize: 18.0
                     ),
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         return S.of(context).verification_code_is_required;
                       }
                       return null;

lib/widgets/mobile/mobile_order_detail.dart

@@ -37,18 +37,18 @@ class MobileOrderDetail extends StatefulWidget {
 }
 
 class MobileOrderDetailState extends State<MobileOrderDetail> {
-  Order order;
+  late Order order;
 
-  LatLng _lastMapPosition;
-  LatLng customerLatLng;
-  LatLng deliveryLatLng;
-  LatLng storeLatLng;
+  late LatLng _lastMapPosition;
+  late LatLng customerLatLng;
+  late LatLng deliveryLatLng;
+  late LatLng storeLatLng;
   final Set<Marker> _markers = {};
   final Set<Polyline> _polyLine = {};
 
-  BitmapDescriptor homeIcon;
-  BitmapDescriptor deliveryIcon;
-  BitmapDescriptor shopIcon;
+  late BitmapDescriptor homeIcon;
+  late BitmapDescriptor deliveryIcon;
+  late BitmapDescriptor shopIcon;
 
   Completer<GoogleMapController> _controller = Completer();
 
@@ -123,7 +123,7 @@ class MobileOrderDetailState extends State<MobileOrderDetail> {
                               width: double.infinity,
                               padding: EdgeInsets.only(top: 0.0, bottom: 16.0),
                               child: Text(
-                                order.cartInfo.businessInfo.name,
+                                order.cartInfo!.businessInfo!.name,
                                 maxLines: 1,
                                 overflow: TextOverflow.ellipsis,
                                 style: TextStyle(
@@ -154,7 +154,7 @@ class MobileOrderDetailState extends State<MobileOrderDetail> {
                               Icons.phone,
                             ),
                             onTap: () {
-                              Utils.launchURL('tel:${order.businessInfo.phone}');
+                              Utils.launchURL('tel:${order.businessInfo!.phone}');
                             },
                           ),
                         ),
@@ -170,8 +170,8 @@ class MobileOrderDetailState extends State<MobileOrderDetail> {
                         onMapCreated: _onMapCreated,
                         initialCameraPosition: CameraPosition(
                           target: LatLng(
-                            double.parse(order.shippingAddress.lat),
-                            double.parse(order.shippingAddress.lng)),
+                            double.parse(order.shippingAddress!.lat),
+                            double.parse(order.shippingAddress!.lng)),
                           zoom: 11.0,
                         ),
                         onCameraMove: _onCameraMove,
@@ -182,14 +182,14 @@ class MobileOrderDetailState extends State<MobileOrderDetail> {
                         ].toSet(),
                       ),
                     ));
-                    if (order.deliveryDistance != null && order.deliveryDistance.distance != null) {
+                    if (order.deliveryDistance != null && order.deliveryDistance!.distance != null) {
                       col.children.add(Container(
                         padding: EdgeInsets.only(top: 6.0, bottom: 6.0),
                         margin: EdgeInsets.only(bottom: 6.0),
                         child: Text(
                           S.of(context).delivery_distance_token(
-                              order.deliveryDistance.distance.text,
-                              order.deliveryDistance.duration.text
+                              order.deliveryDistance!.distance!.text,
+                              order.deliveryDistance!.duration!.text
                           ),
                         ),
                         decoration: BoxDecoration(
@@ -205,7 +205,7 @@ class MobileOrderDetailState extends State<MobileOrderDetail> {
                   }
                 }
 
-                for (CartLineItem lineItem in order.cartInfo.productList) {
+                for (CartLineItem lineItem in order.cartInfo!.productList) {
 
                   col.children.add(Container(
                     padding: EdgeInsets.only(top: 16.0, bottom: 0.0),
@@ -213,7 +213,7 @@ class MobileOrderDetailState extends State<MobileOrderDetail> {
                       mainAxisAlignment: MainAxisAlignment.start,
                       crossAxisAlignment: CrossAxisAlignment.start,
                       children: <Widget>[
-                        Util.showImage('${lineItem.product.imagePath}',
+                        Util.showImage('${lineItem.product!.imagePath}',
                           width: 40.0,
                           height: 40.0,
                           fit: BoxFit.fill,
@@ -251,7 +251,7 @@ class MobileOrderDetailState extends State<MobileOrderDetail> {
                           width: 30.0,
                           alignment: Alignment.centerRight,
                           child: Text(
-                            'x${lineItem.quantity.round()}',
+                            'x${lineItem.quantity!.round()}',
                             style: TextStyle(
                               fontSize: 14.0,
                             ),
@@ -313,8 +313,8 @@ class MobileOrderDetailState extends State<MobileOrderDetail> {
                     ],
                   ),
                 );
-                for (var i = 0; i < order.cartInfo.extraFeeList.length; i++) {
-                  ExtraFee extraFee = order.cartInfo.extraFeeList[i];
+                for (var i = 0; i < order.cartInfo!.extraFeeList!.length; i++) {
+                  ExtraFee extraFee = order.cartInfo!.extraFeeList![i];
                   col.children.add(
                     Row(
                       mainAxisAlignment: MainAxisAlignment.start,
@@ -338,7 +338,7 @@ class MobileOrderDetailState extends State<MobileOrderDetail> {
                           width: 100.0,
                           alignment: Alignment.centerRight,
                           child: Text(
-                            '${extraFee.price.toStringAsFixed(2)}',
+                            '${extraFee.price!.toStringAsFixed(2)}',
                             style: TextStyle(
                               fontSize: 15.0,
                             ),
@@ -371,7 +371,7 @@ class MobileOrderDetailState extends State<MobileOrderDetail> {
                         width: 100.0,
                         alignment: Alignment.centerRight,
                         child: Text(
-                          '${order.totalPrice.toStringAsFixed(2)}',
+                          '${order.totalPrice!.toStringAsFixed(2)}',
                           style: TextStyle(
                             fontSize: 18.0,
                             fontWeight: FontWeight.bold,
@@ -481,7 +481,7 @@ class MobileOrderDetailState extends State<MobileOrderDetail> {
                             margin: EdgeInsets.only(top: 10.0, bottom: 10.0),
                             alignment: Alignment.centerRight,
                             child: Text(
-                              '${order.cartInfo.businessInfo.fullAddress}',
+                              '${order.cartInfo!.businessInfo!.fullAddress}',
                               style: TextStyle(
                                 color: Colors.black38,
                               ),
@@ -908,19 +908,19 @@ class MobileOrderDetailState extends State<MobileOrderDetail> {
                       crossAxisAlignment: CrossAxisAlignment.start,
                       children: <Widget>[
                         Container(
-                          child: fulfillment.shippingMethod.isNotEmpty && fulfillment.trackingNumber != null && fulfillment.trackingNumber.isNotEmpty ?
+                          child: fulfillment.shippingMethod!.isNotEmpty && fulfillment.trackingNumber != null && fulfillment.trackingNumber!.isNotEmpty ?
                           Text(
                             '${fulfillment.shippingMethod} ${fulfillment.trackingNumber}',
                             overflow: TextOverflow.ellipsis,
                             maxLines: 1,
-                          ) : (fulfillment.shippingMethod.isNotEmpty ? Text(
+                          ) : (fulfillment.shippingMethod!.isNotEmpty ? Text(
                             '${fulfillment.shippingMethod}',
                             overflow: TextOverflow.ellipsis,
                             maxLines: 1,
                           ) : SizedBox.shrink()),
                         ),
                         Container(
-                          child: fulfillment.note != null && fulfillment.note.isNotEmpty ?
+                          child: fulfillment.note != null && fulfillment.note!.isNotEmpty ?
                           Text(
                             '${fulfillment.note}',
                             style: TextStyle(
@@ -1060,12 +1060,12 @@ class MobileOrderDetailState extends State<MobileOrderDetail> {
 
           if (!kIsWeb) {
             if (order.shippingMethod == 'store-delivery' && order.status != Constants.STATUS_COMPLETE && order.status != Constants.STATUS_CANCELLED) {
-              storeLatLng = LatLng(double.parse(order.businessInfo.address.lat),
-                  double.parse(order.businessInfo.address.lng));
-              customerLatLng = LatLng(double.parse(order.shippingAddress.lat),
-                  double.parse(order.shippingAddress.lng));
+              storeLatLng = LatLng(double.parse(order.businessInfo!.address!.lat),
+                  double.parse(order.businessInfo!.address!.lng));
+              customerLatLng = LatLng(double.parse(order.shippingAddress!.lat),
+                  double.parse(order.shippingAddress!.lng));
               deliveryLatLng =
-                  LatLng(order.shipperPosition.lat, order.shipperPosition.lng);
+                  LatLng(order.shipperPosition!.lat, order.shipperPosition!.lng);
 
               _polyLine.clear();
               _polyLine.add(
@@ -1078,7 +1078,7 @@ class MobileOrderDetailState extends State<MobileOrderDetail> {
                       ],
                       width: 3,
                       points: [
-                        order.shipperPosition.lat != 0.0 ? deliveryLatLng : storeLatLng,
+                        order.shipperPosition!.lat != 0.0 ? deliveryLatLng : storeLatLng,
                         customerLatLng,
                       ]
                   )
@@ -1103,12 +1103,12 @@ class MobileOrderDetailState extends State<MobileOrderDetail> {
                   title: S
                       .of(context)
                       .customer,
-                  snippet: order.shippingAddress.addressLine1,
+                  snippet: order.shippingAddress!.addressLine1,
                 ),
                 icon: homeIcon,
               ));
-              if (order.shipperPosition.lat != 0.0 &&
-                  order.shipperPosition.lng != 0.0) {
+              if (order.shipperPosition!.lat != 0.0 &&
+                  order.shipperPosition!.lng != 0.0) {
                 _markers.add(Marker(
                   markerId: MarkerId('shipper_position'),
                   position: deliveryLatLng,

lib/widgets/mobile/mobile_orders.dart

@@ -152,7 +152,7 @@ class MobileOrdersState extends State<MobileOrders> with SingleTickerProviderSta
         row.children.add(Expanded(
           child: Container(
             child: Text(
-              order.cartInfo.productList[0].name,
+              order.cartInfo!.productList![0].name,
               style: TextStyle(
                 fontSize: 14.0,
               ),
@@ -161,7 +161,7 @@ class MobileOrdersState extends State<MobileOrders> with SingleTickerProviderSta
             ),
           ),
         ));
-        if (order.cartInfo.productList.length > 1) {
+        if (order.cartInfo!.productList!.length > 1) {
           row.children.add(Container(
             child: Text(
               S.of(context).and_more_item_token(Utils.getProductLineInOrder(order.cartInfo)),
@@ -176,7 +176,7 @@ class MobileOrdersState extends State<MobileOrders> with SingleTickerProviderSta
           width: 80.0,
           alignment: Alignment.centerRight,
           child: Text(
-            '\$${order.totalPrice.toStringAsFixed(2)}',
+            '\$${order.totalPrice!.toStringAsFixed(2)}',
             style: TextStyle(
               fontSize: 16.0,
               fontWeight: FontWeight.bold,
@@ -291,7 +291,7 @@ class MobileOrdersState extends State<MobileOrders> with SingleTickerProviderSta
                 mainAxisAlignment: MainAxisAlignment.start,
                 children: <Widget>[
                   Container(
-                    child: Util.showImage('${order.cartInfo.businessInfo.picUrl}',
+                    child: Util.showImage('${order.cartInfo!.businessInfo!.picUrl}',
                       width: 32.0,
                       height: 32.0,
                       fit: BoxFit.fill,
@@ -307,7 +307,7 @@ class MobileOrdersState extends State<MobileOrders> with SingleTickerProviderSta
                           children: <Widget>[
                             Container(
                               child: Text(
-                                '${order.cartInfo.businessInfo.name}',
+                                '${order.cartInfo!.businessInfo!.name}',
                                 style: TextStyle(
                                   fontSize: 20.0,
                                 ),

lib/widgets/mobile/mobile_pay_now.dart

@@ -30,9 +30,9 @@ class MobilePayNow extends StatefulWidget {
 }
 
 class MobilePayNowState extends State<MobilePayNow> {
-  Order order;
-  List<PaymentPlatform> paymentPlatforms;
-  User _user;
+  late Order order;
+  late List<PaymentPlatform> paymentPlatforms;
+  late User _user;
 
   
   @override
@@ -74,7 +74,7 @@ class MobilePayNowState extends State<MobilePayNow> {
                       ),
                     ),
                     Text(
-                      '\$${order.totalPrice.toStringAsFixed(2)}',
+                      '\$${order.totalPrice!.toStringAsFixed(2)}',
                       style: TextStyle(
                         fontSize: 24.0,
                         fontWeight: FontWeight.bold,
@@ -91,7 +91,7 @@ class MobilePayNowState extends State<MobilePayNow> {
                     )
                 ),
               ),
-              store.state.deviceId != null && store.state.deviceId.isNotEmpty || store.state.tableNumber != null && store.state.tableNumber.isNotEmpty ?
+              store.state.deviceId != null && store.state.deviceId!.isNotEmpty || store.state.tableNumber != null && store.state.tableNumber!.isNotEmpty ?
               GestureDetector(
                 child: Container(
                   padding: EdgeInsets.only(top: 20.0, bottom: 20.0, left: 16.0, right: 16.0),

lib/widgets/mobile/mobile_product_detail_page.dart

@@ -23,10 +23,10 @@ import '../../widgets/general/add_remove_button.dart';
 import '../../widgets/general/carousel.dart';
 import '../../widgets/general/show_price.dart';
 
-MediaQueryData mediaQuery;
-double statusBarHeight;
-double screenHeight;
-double screenWidth;
+late MediaQueryData mediaQuery;
+late double statusBarHeight;
+late double screenHeight;
+late double screenWidth;
 
 class MobileProductDetailPage extends StatefulWidget {
   final Business business;
@@ -44,18 +44,18 @@ class MobileProductDetailPage extends StatefulWidget {
 
 class MobileProductDetailPageState extends State<MobileProductDetailPage>
     with SingleTickerProviderStateMixin {
-  ShopScrollCoordinator _shopCoordinator;
-  ShopScrollController _pageScrollController;
+  late ShopScrollCoordinator _shopCoordinator;
+  late ShopScrollController _pageScrollController;
 
-  TabController _tabController;
+  late TabController _tabController;
 
-  double _sliverAppBarInitHeight;
-  double _sliverAppBarMaxHeight;
+  late double _sliverAppBarInitHeight;
+  late double _sliverAppBarMaxHeight;
   final double _tabBarHeight = 50;
 
-  ProductDetail productDetail;
+  late ProductDetail productDetail;
 
-  bool refresh;
+  late bool refresh;
 
   @override
   Widget build(BuildContext context) {
@@ -204,7 +204,7 @@ class MobileProductDetailPageState extends State<MobileProductDetailPage>
                         mainAxisAlignment: MainAxisAlignment.start,
                         crossAxisAlignment: CrossAxisAlignment.start,
                         children: <Widget>[
-                          (productDetail.subproducts.length > 0) ?
+                          (productDetail.subproducts!.length > 0) ?
                           subProducts(productDetail.subproducts) :
                           SizedBox.shrink(),
                           Container(
@@ -219,7 +219,7 @@ class MobileProductDetailPageState extends State<MobileProductDetailPage>
                           Container(
                             padding: EdgeInsets.only(left: 10.0, right: 10.0),
                             child: (productDetail.description2 != null &&
-                                    !productDetail.description2.isEmpty)
+                                    !productDetail.description2!.isEmpty)
                                 ? Text(
                                     '${productDetail.description2}',
                                     style: TextStyle(
@@ -343,7 +343,7 @@ class MobileProductDetailPageState extends State<MobileProductDetailPage>
       Container(
         padding: EdgeInsets.symmetric(horizontal: 12.0, vertical: 5.0),
         child: Util.showImage(
-          'https:${subproduct.product.image}',
+          'https:${subproduct.product!.image}',
           width: 48,
           height: 48,
           fit: BoxFit.contain,
@@ -363,7 +363,7 @@ class MobileProductDetailPageState extends State<MobileProductDetailPage>
                   child: Container(
                     padding: EdgeInsets.only(left: 12, top: 5),
                     child: Text(
-                      subproduct.product.name,
+                      subproduct.product!.name,
                       style: TextStyle(
                         fontSize: 15.0,
                       ),
@@ -374,7 +374,7 @@ class MobileProductDetailPageState extends State<MobileProductDetailPage>
                   width: 80,
                   padding: EdgeInsets.only(left: 12, top: 5, right: 12),
                   child: Text(
-                    '${subproduct.product.price.toStringAsFixed(2)}',
+                    '${subproduct.product!.price!.toStringAsFixed(2)}',
                     style: TextStyle(
                       fontSize: 13,
                       decoration: TextDecoration.lineThrough,
@@ -386,7 +386,7 @@ class MobileProductDetailPageState extends State<MobileProductDetailPage>
                   width: 60,
                   padding: EdgeInsets.only(left: 12, top: 5, right: 12),
                   child: Text(
-                    'x${subproduct.quantity.toStringAsFixed(0)}',
+                    'x${subproduct.quantity!.toStringAsFixed(0)}',
                     style: TextStyle(
                       fontSize: 13,
                     ),
@@ -398,7 +398,7 @@ class MobileProductDetailPageState extends State<MobileProductDetailPage>
             Container(
               padding: EdgeInsets.only(left: 12, top: 12, right: 12),
               child: Text(
-                '${subproduct.product.description}',
+                '${subproduct.product!.description}',
                 style: TextStyle(
                   fontSize: 12,
                   color: Colors.black45,
@@ -419,9 +419,9 @@ class MobileProductDetailPageState extends State<MobileProductDetailPage>
     var pages = <Widget>[];
     List<String> images = [];
     images.add(productDetail.image);
-    for (var i = 0; i < productDetail.images.length; i++) {
+    for (var i = 0; i < productDetail.images!.length; i++) {
       // print('>>https:' + productDetail.images[i].image);
-      images.add(productDetail.images[i].image);
+      images.add(productDetail.images![i].image);
     }
 
     for (var i = 0; i < images.length; i++) {

lib/widgets/mobile/mobile_product_item.dart

@@ -98,7 +98,7 @@ class MobileProductItemState extends State<MobileProductItem> {
                           new Container(
                             child: widget.business.showMonthlySold ?
                             Text(
-                              S.of(context).sold_per_month_token(widget.product.monthSales.toStringAsFixed(0)),
+                              S.of(context).sold_per_month_token(widget.product.monthSales!.toStringAsFixed(0)),
                               style: new TextStyle(
                                   fontSize: 9.0
                               ),

lib/widgets/mobile/mobile_renew_license.dart

@@ -97,7 +97,7 @@ class MobileRenewLicenseState extends State<MobileRenewLicense> {
           ),
           autofocus: true,
           validator: (String? value) {
-            if (value.trim().isEmpty) {
+            if (value!.trim().isEmpty) {
               return S.of(context).please_enter_group_number;
             }
             return null;

lib/widgets/mobile/mobile_renew_minioffice.dart

@@ -104,7 +104,7 @@ class MobileRenewMiniOfficeState extends State<MobileRenewMiniOffice> {
     );
   }
 
-  Widget buildLine(String name, String value, {double nameSize, double valueSize}) {
+  Widget buildLine(String name, String value, {double? nameSize, double? valueSize}) {
     Row row = Row(
       mainAxisAlignment: MainAxisAlignment.start,
       crossAxisAlignment: CrossAxisAlignment.start,

lib/widgets/mobile/mobile_reset_password.dart

@@ -27,10 +27,10 @@ class MobileResetPasswordState extends State<MobileResetPassword> {
   final passwordController = TextEditingController();
   final passwordAgainController = TextEditingController();
 
-  bool passwordVisible;
-  bool passwordAgainVisible;
+  late bool passwordVisible;
+  late bool passwordAgainVisible;
 
-  bool canReset;
+  late bool canReset;
 
   @override
   void initState() {
@@ -105,7 +105,7 @@ class MobileResetPasswordState extends State<MobileResetPassword> {
                         fontSize: 18.0
                     ),
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         return S.of(context).password_is_required;
                       }
                       return null;
@@ -159,10 +159,10 @@ class MobileResetPasswordState extends State<MobileResetPassword> {
                         fontSize: 18.0
                     ),
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         return S.of(context).password_is_required;
                       }
-                      if (value.trim() != passwordController.text.trim()) {
+                      if (value!.trim() != passwordController.text.trim()) {
                         return S.of(context).password_is_not_match_password_again;
                       }
                       return null;

lib/widgets/mobile/mobile_search_place.dart

@@ -107,7 +107,7 @@ class MobileSearchPlaceState extends State<MobileSearchPlace> {
     );
     if (result is DioError) {
       if (result.response != null) {
-        throw RuntimeError(result.response.data['message']);
+        throw RuntimeError(result.response!.data['message']);
       } else {
         throw RuntimeError(result.message);
       }

lib/widgets/mobile/mobile_set_password.dart

@@ -28,10 +28,10 @@ class MobileSetPasswordState extends State<MobileSetPassword> {
   final passwordController = TextEditingController();
   final passwordAgainController = TextEditingController();
 
-  bool passwordVisible;
-  bool passwordAgainVisible;
+  late bool passwordVisible;
+  late bool passwordAgainVisible;
 
-  bool canReset;
+  late bool canReset;
 
   @override
   void initState() {
@@ -106,7 +106,7 @@ class MobileSetPasswordState extends State<MobileSetPassword> {
                         fontSize: 18.0
                     ),
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         return S.of(context).password_is_required;
                       }
                       return null;
@@ -160,10 +160,10 @@ class MobileSetPasswordState extends State<MobileSetPassword> {
                         fontSize: 18.0
                     ),
                     validator: (String? value) {
-                      if (value.trim().isEmpty) {
+                      if (value!.trim().isEmpty) {
                         return S.of(context).password_is_required;
                       }
-                      if (value.trim() != passwordController.text.trim()) {
+                      if (value!.trim() != passwordController.text.trim()) {
                         return S.of(context).password_is_not_match_password_again;
                       }
                       return null;

lib/widgets/mobile/mobile_store_product_search.dart

@@ -105,7 +105,7 @@ class MobileStoreProductSearchState extends State<MobileStoreProductSearch> {
     );
     if (result is DioError) {
       if (result.response != null) {
-        throw RuntimeError(result.response.data);
+        throw RuntimeError(result.response!.data);
       } else {
         throw RuntimeError(result.message);
       }

lib/widgets/mobile/mobile_user_profile.dart

@@ -27,10 +27,10 @@ class MobileUserProfile extends StatefulWidget {
 }
 
 class MobileUserProfileState extends State<MobileUserProfile> {
-  User _user;
+  late User _user;
 
-  bool _showProgress;
-  double _progress;
+  late bool _showProgress;
+  late double _progress;
 
   @override
   Widget build(BuildContext context) {
@@ -229,7 +229,7 @@ class MobileUserProfileState extends State<MobileUserProfile> {
                 ),
                 Container(
                   child: Text(
-                    _user.mobile != null && _user.mobile.isNotEmpty ? Utils.safePhoneNumber(_user.mobile) : S.of(context).not_binding,
+                    _user.mobile != null && _user.mobile!.isNotEmpty ? Utils.safePhoneNumber(_user.mobile) : S.of(context).not_binding,
                     style: TextStyle(
                       color: Colors.grey,
                     ),
@@ -282,7 +282,7 @@ class MobileUserProfileState extends State<MobileUserProfile> {
                 ),
                 Container(
                   child: Text(
-                    _user.email != null && _user.email.isNotEmpty ? Utils.safePhoneNumber(_user.email) : S.of(context).not_binding,
+                    _user.email != null && _user.email!.isNotEmpty ? Utils.safePhoneNumber(_user.email) : S.of(context).not_binding,
                     style: TextStyle(
                       color: Colors.grey,
                     ),
@@ -393,7 +393,7 @@ class MobileUserProfileState extends State<MobileUserProfile> {
                   ),
                   autofocus: true,
                   validator: (String? value) {
-                    if (value.trim().isEmpty) {
+                    if (value!.trim().isEmpty) {
                       return S.of(context).nickname_is_required;
                     }
                     return null;

lib/widgets/mobile/mobile_view_blog.dart

@@ -28,7 +28,7 @@ class MobileViewBlog extends StatefulWidget {
 }
 
 class MobileViewBlogState extends State<MobileViewBlog> {
-  Blog blog;
+  late Blog blog;
 
   @override
   void initState() {

lib/widgets/mobile/mobile_view_ticket.dart

@@ -34,7 +34,7 @@ class MobileViewTicket extends StatefulWidget {
 class MobileViewTicketState extends State<MobileViewTicket> {
   final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
 
-  Ticket ticket;
+  late Ticket ticket;
 
   final issueMsgController = TextEditingController();
 
@@ -123,7 +123,7 @@ class MobileViewTicketState extends State<MobileViewTicket> {
           width: double.maxFinite,
           padding: EdgeInsets.only(top: 8.0, left: 16.0, right: 16.0, bottom: 24.0),
           child: Text(
-            '${ticket.issue.msg}',
+            '${ticket.issue!.msg}',
             style: TextStyle(
               color: Colors.black54,
               fontSize: 14.0,
@@ -141,7 +141,7 @@ class MobileViewTicketState extends State<MobileViewTicket> {
         Container(
           width: double.maxFinite,
           padding: EdgeInsets.only(top: 16.0, bottom: 16.0, left: 16.0, right: 16.0),
-          child: showGalleryImages(mainContext, ticket.issue.files),
+          child: showGalleryImages(mainContext, ticket.issue!.files),
           decoration: BoxDecoration(
             border: Border(
               bottom: BorderSide(
@@ -171,7 +171,7 @@ class MobileViewTicketState extends State<MobileViewTicket> {
       ],
     );
 
-    if (ticket.followUps.length > 0) {
+    if (ticket.followUps!.length > 0) {
       view.children.add(
         Container(
           width: double.maxFinite,
@@ -185,8 +185,8 @@ class MobileViewTicketState extends State<MobileViewTicket> {
           ),
         ),
       );
-      for (int i = 0; i < ticket.followUps.length; i++) {
-        FollowUp followUp = ticket.followUps[i];
+      for (int i = 0; i < ticket.followUps!.length; i++) {
+        FollowUp followUp = ticket.followUps![i];
         view.children.add(
           Container(
             width: double.maxFinite,
@@ -294,7 +294,7 @@ class MobileViewTicketState extends State<MobileViewTicket> {
               ),
               autofocus: false,
               validator: (String? value) {
-                if (value.trim().isEmpty) {
+                if (value!.trim().isEmpty) {
                   return S.of(context).this_field_is_required;
                 }
                 return null;
@@ -353,7 +353,7 @@ class MobileViewTicketState extends State<MobileViewTicket> {
       ),
     );
 
-    if (ticket.followUps.length > 0) {
+    if (ticket.followUps!.length > 0) {
       view.children.add(
         Container(
           width: double.maxFinite,
@@ -393,7 +393,7 @@ class MobileViewTicketState extends State<MobileViewTicket> {
             padding: EdgeInsets.only(left: 20.0, right: 20.0, top: 0.0, bottom: 30.0),
             child: TextLink(
               S.of(context).new_ticket,
-              '/new-ticket/${ticket.store.id}',
+              '/new-ticket/${ticket.store!.id}',
             ),
           ),
       );
@@ -690,7 +690,7 @@ class MobileViewTicketState extends State<MobileViewTicket> {
                       child: Text(S.of(context).ok),
                       onPressed: () {
                         Routes.router.navigateTo(context,
-                          '/my-support/${ticket.store.id}',
+                          '/my-support/${ticket.store!.id}',
                           replace: true,
                         );
                       },

lib/widgets/mobile/product_item.dart

@@ -64,7 +64,7 @@ class ProductItemState extends State<ProductItem> {
           width: widget.imageWidth,
           height: widget.imageWidth,
           child: GestureDetector(
-            child: onHover && widget.product.secondImagePath.isNotEmpty ?
+            child: onHover && widget.product.secondImagePath!.isNotEmpty ?
             Util.showImage('${widget.product.secondImagePath}',
               fit: BoxFit.fill,
             ) :
@@ -127,7 +127,7 @@ class ProductItemState extends State<ProductItem> {
                 new Container(
                   child: widget.business.showMonthlySold ?
                   Text(
-                    S.of(context).sold_per_month_token(widget.product.monthSales.toStringAsFixed(0)),
+                    S.of(context).sold_per_month_token(widget.product.monthSales!.toStringAsFixed(0)),
                     style: new TextStyle(
                         fontSize: 9.0
                     ),
@@ -157,7 +157,7 @@ class ProductItemState extends State<ProductItem> {
           width: widget.imageWidth,
           height: widget.imageWidth,
           child: GestureDetector(
-            child: onHover && widget.product.secondImagePath.isNotEmpty ?
+            child: onHover && widget.product.secondImagePath!.isNotEmpty ?
             Util.showImage('${widget.product.secondImagePath}',
               fit: BoxFit.fill,
             ) :
@@ -212,7 +212,7 @@ class ProductItemState extends State<ProductItem> {
                       new Container(
                         child: widget.business.showMonthlySold ?
                         Text(
-                          S.of(context).sold_per_month_token(widget.product.monthSales.toStringAsFixed(0)),
+                          S.of(context).sold_per_month_token(widget.product.monthSales!.toStringAsFixed(0)),
                           style: new TextStyle(
                               fontSize: 9.0
                           ),

lib/widgets/mobile/product_search.dart

@@ -113,7 +113,7 @@ class ProductSearchState extends State<ProductSearch> {
     );
     if (result is DioError) {
       if (result.response != null) {
-        throw RuntimeError(result.response.data);
+        throw RuntimeError(result.response!.data);
       } else {
         throw RuntimeError(result.message);
       }

lib/widgets/mobile/shop.dart

@@ -37,10 +37,10 @@ import 'product_item.dart';
 import 'product_search.dart';
 import 'shopping_cart_bar.dart';
 
-MediaQueryData mediaQuery;
-double statusBarHeight;
-double screenWidth;
-double screenHeight;
+late MediaQueryData mediaQuery;
+late double statusBarHeight;
+late double screenWidth;
+late double screenHeight;
 
 class Shop extends StatefulWidget {
   final int businessId;
@@ -56,10 +56,10 @@ class ShopState extends State<Shop>
 
   GlobalKey<ScaffoldState> _scaffoldKey = new GlobalKey<ScaffoldState>();
 
-  Business _business;
-  List<CategoryProducts> _categoryProducts;
-  List<Product> _featuredProducts;
-  List<Product> _hotSaleProducts;
+  late Business _business;
+  late List<CategoryProducts> _categoryProducts;
+  late List<Product> _featuredProducts;
+  late List<Product> _hotSaleProducts;
 
   List<dynamic> _prompts = [];
   bool checkCloseFlag = false;
@@ -79,22 +79,22 @@ class ShopState extends State<Shop>
 
   bool refresh = false;
 
-  ShopScrollCoordinator _shopCoordinator;
-  ShopScrollController _pageScrollController;
-  TabController _tabController;
+  late ShopScrollCoordinator _shopCoordinator;
+  late ShopScrollController _pageScrollController;
+  late TabController _tabController;
   final double _sliverAppBarInitHeight = 150.0;
   final double _tabBarHeight = 50.0;
-  double _sliverAppBarMaxHeight;
+  late double _sliverAppBarMaxHeight;
 
-  ShopScrollController _listScrollController1;
-  ShopScrollController _listScrollController2;
-  ShopScrollController _listScrollController3;
+  late ShopScrollController _listScrollController1;
+  late ShopScrollController _listScrollController2;
+  late ShopScrollController _listScrollController3;
 
   AnimationPointManager _animationPointManager = AnimationPointManager();
   GlobalKey stackKey = GlobalKey();
   GlobalKey endKey = GlobalKey();
 
-  List<Comment> comments;
+  late List<Comment> comments;
   int _commentPage = 1;
   int _commentPageCount = 1;
   bool _commentLoadingFinish = false;
@@ -102,13 +102,13 @@ class ShopState extends State<Shop>
   RefreshController(initialRefresh: true);
 
   PanelController panelController = PanelController();
-  SlidingUpPanel _slidUpShoppingCart;
+  late SlidingUpPanel _slidUpShoppingCart;
 
-  SliverPersistentHeader promotHeader;
+  late SliverPersistentHeader promotHeader;
 
   bool _animationFinish = true;
 
-  Carousel slidingGellery;
+  late Carousel slidingGellery;
 
   // StreamSubscription onProductWillAddToCartSubscription;
   // StreamSubscription onProductWillRemoveFromCartSubscription;
@@ -247,7 +247,7 @@ class ShopState extends State<Shop>
       mainAxisAlignment: MainAxisAlignment.start,
       children: <Widget>[],
     );
-    for (var i = 0; i < _business.promoProducts.length; i++) {
+    for (var i = 0; i < _business.promoProducts!.length; i++) {
       promotRow.children.add(Container(
         padding: EdgeInsets.only(
           left: 10.0,
@@ -286,17 +286,17 @@ class ShopState extends State<Shop>
             GestureDetector(
               child: Container(
                 child: Util.showImage(
-                  _business.promoProducts[i].imagePath,
+                  _business.promoProducts![i].imagePath,
                   width: 110.0,
                 ),
               ),
               onTap: () {
-                _showProductDetail(_business.promoProducts[i]);
+                _showProductDetail(_business.promoProducts![i]);
               },
             ),
             Container(
               child: Text(
-                _business.promoProducts[i].name,
+                _business.promoProducts![i].name,
                 maxLines: 2,
                 overflow: TextOverflow.ellipsis,
                 style: TextStyle(fontSize: 14.0),
@@ -306,13 +306,13 @@ class ShopState extends State<Shop>
               mainAxisAlignment: MainAxisAlignment.spaceBetween,
               children: <Widget>[
                 ShowPrice(
-                  _business.promoProducts[i].price,
+                  _business.promoProducts![i].price,
                   currencySign: '\$',
-                  regularPrice: _business.promoProducts[i].regularPrice,
+                  regularPrice: _business.promoProducts![i].regularPrice,
                 ),
                 Container(
                   child: AddRemoveButton(
-                    product: _business.promoProducts[i],
+                    product: _business.promoProducts![i],
                     business: _business,
                     addOnly: true,
                   ),
@@ -581,7 +581,7 @@ class ShopState extends State<Shop>
               mainAxisAlignment: MainAxisAlignment.start,
               children: <Widget>[],
             );
-            if (comment.images.length > 0) {
+            if (comment.images!.length > 0) {
               for (ProductImage image in comment.images) {
                 imageRow.children.add(
                   GestureDetector(
@@ -609,7 +609,7 @@ class ShopState extends State<Shop>
             }
             Widget replyWidget = SizedBox.shrink();
             if (comment.replyFromStore != null &&
-                comment.replyFromStore.isNotEmpty) {
+                comment.replyFromStore!.isNotEmpty) {
               replyWidget = Container(
                 child: Column(
                   mainAxisAlignment: MainAxisAlignment.start,
@@ -681,7 +681,7 @@ class ShopState extends State<Shop>
                         Container(
                           child: SmoothStarRating(
                             starCount: 5,
-                            rating: comment.rating.toDouble(),
+                            rating: comment.rating!.toDouble(),
                             size: 12.0,
                             filledIconData: Icons.star,
                             color: Colors.green,
@@ -772,18 +772,18 @@ class ShopState extends State<Shop>
       children: <Widget>[],
     );
     addressColumn.children.add(new Text(
-      _business.address.addressLine1 +
-          (_business.address.addressLine2.isNotEmpty
-              ? ' ' + _business.address.addressLine2
+      _business.address!.addressLine1! +
+          (_business.address!.addressLine2!.isNotEmpty
+              ? ' ' + _business.address!.addressLine2
               : ''),
       style: new TextStyle(fontSize: 13.0, color: const Color(0xFFEEEEEE)),
     ));
     addressColumn.children.add(new Text(
-      _business.address.city +
+      _business.address!.city! +
           ', ' +
-          _business.address.state +
+          _business.address!.state +
           ', ' +
-          _business.address.zip,
+          _business.address!.zip,
       style: new TextStyle(fontSize: 13.0, color: const Color(0xFFEEEEEE)),
     ));
 
@@ -800,16 +800,16 @@ class ShopState extends State<Shop>
         color: Colors.white,
       ));
       distanceRow.children.add(new Text(
-        _business.distanceInfo.distance != null
-            ? _business.distanceInfo.distance.text
+        _business.distanceInfo!.distance != null
+            ? _business.distanceInfo!.distance!.text
             : '***' + ' / ',
         style: new TextStyle(color: const Color(0xFFEEEEEE), fontSize: 13.0),
       ));
       var duration = Duration(
-          seconds: (_business.distanceInfo.duration != null
-              ? _business.distanceInfo.duration.value
-              : 30) +
-              _business.shippingTime * 60);
+          seconds: (_business.distanceInfo!.duration != null
+              ? _business.distanceInfo!.duration!.value
+              : 30)! +
+              _business.shippingTime! * 60);
       var hours = duration.inHours.remainder(60);
       var minutes = duration.inMinutes.remainder(60);
       distanceRow.children.add(new Text(
@@ -910,9 +910,9 @@ class ShopState extends State<Shop>
                             color: Colors.white,
                           ),
                           new Text(
-                            _business.openingTime[0].openTime +
+                            _business.openingTime![0].openTime! +
                                 ':00 - ' +
-                                _business.openingTime[0].closeTime +
+                                _business.openingTime![0].closeTime +
                                 ':00',
                             style: new TextStyle(
                                 fontSize: 13.0, color: const Color(0xFFEEEEEE)),
@@ -941,7 +941,7 @@ class ShopState extends State<Shop>
       mainAxisAlignment: MainAxisAlignment.start,
       mainAxisSize: MainAxisSize.min,
       children: <Widget>[
-        _business.bulletin.isNotEmpty ? Row(
+        _business.bulletin!.isNotEmpty ? Row(
           crossAxisAlignment: CrossAxisAlignment.start,
           children: <Widget>[
             Container(
@@ -956,7 +956,7 @@ class ShopState extends State<Shop>
               width: mediaQuery.size.width - 30.0,
               padding: EdgeInsets.only(right: 10.0, bottom: 10.0),
               child: new Text(
-                _business.bulletin.isEmpty ? '' : _business.bulletin,
+                _business.bulletin!.isEmpty ? '' : _business.bulletin,
                 softWrap: true,
                 style: new TextStyle(
                     fontSize: 12.0, color: const Color(0xFFDDDDDD)),
@@ -965,7 +965,7 @@ class ShopState extends State<Shop>
             ),
           ],
         ) : SizedBox.shrink(),
-        _business.description.isNotEmpty ? Column(
+        _business.description!.isNotEmpty ? Column(
           mainAxisAlignment: MainAxisAlignment.start,
           crossAxisAlignment: CrossAxisAlignment.start,
           children: [
@@ -1009,7 +1009,7 @@ class ShopState extends State<Shop>
           padding: EdgeInsets.only(left: 10.0, right: 10.0, bottom: 10.0),
           child: slidingGellery,
         ) : SizedBox.shrink(),
-        _business.policy.isNotEmpty ? Column(
+        _business.policy!.isNotEmpty ? Column(
           mainAxisAlignment: MainAxisAlignment.start,
           crossAxisAlignment: CrossAxisAlignment.start,
           children: [
@@ -1098,11 +1098,11 @@ class ShopState extends State<Shop>
 
   List<Widget> _buildBanners(BuildContext context) {
     var pages = <Widget>[];
-    for (var i = 0; i < _business.slideImages.length; i++) {
+    for (var i = 0; i < _business.slideImages!.length; i++) {
       pages.add(new GestureDetector(
         child: new Container(
           child: Util.showImage(
-            _business.slideImages[i].imageUrl,
+            _business.slideImages![i].imageUrl,
             fit: BoxFit.cover,
           ),
         ),
@@ -1139,11 +1139,11 @@ class ShopState extends State<Shop>
               CartInfo cartInfo =
               Utils.getCartInfoByBusiness(store.state.cartInfos, _business);
               if (cartInfo != null &&
-                  cartInfo.businessInfo.id == _business.id &&
+                  cartInfo.businessInfo!.id == _business.id &&
                   cartInfo.productList != null) {
-                for (var i = 0; i < cartInfo.productList.length; i++) {
-                  if (cartInfo.productList[i].product.categoryId == cp.id) {
-                    qtyInCategory += cartInfo.productList[i].quantity.round();
+                for (var i = 0; i < cartInfo.productList!.length; i++) {
+                  if (cartInfo.productList![i].product!.categoryId == cp.id) {
+                    qtyInCategory += cartInfo.productList![i].quantity!.round();
                   }
                 }
               }
@@ -1213,7 +1213,7 @@ class ShopState extends State<Shop>
   }
 
   void _selectCategory(int index) {
-    if (displayProductByCategoryClick && _categoryProducts[index].id > 0) {
+    if (displayProductByCategoryClick && _categoryProducts[index].id! > 0) {
       categoryId = _categoryProducts[index].id;
       loadProducts();
       return;
@@ -1221,7 +1221,7 @@ class ShopState extends State<Shop>
     double height = 0.0;
     for (int i = 0; i < index; ++i) {
       height += _categoryDescHeight +
-          _categoryProducts[i].products.length * _productHeight;
+          _categoryProducts[i].products!.length * _productHeight;
     }
     if (height > _listScrollController1.position.maxScrollExtent) {
       height = _listScrollController1.position.maxScrollExtent;
@@ -1237,7 +1237,7 @@ class ShopState extends State<Shop>
       _categoryIndexChange = false;
     });
     print(
-        'height: $height, index: $index, ${_categoryProducts[0].products.length}');
+        'height: $height, index: $index, ${_categoryProducts[0].products!.length}');
     if (mounted) {
       setState(() {
         _categoryIndex = index;
@@ -1272,7 +1272,7 @@ class ShopState extends State<Shop>
     if (height > 0) {
       for (int i = 0; i < _categoryProducts.length; ++i) {
         double categoryHeight = _categoryDescHeight +
-            _categoryProducts[i].products.length * _productHeight;
+            _categoryProducts[i].products!.length * _productHeight;
         if (height >= cHeight && height < cHeight + categoryHeight) {
           return i;
         }
@@ -1311,7 +1311,7 @@ class ShopState extends State<Shop>
   int numCategoriesHasProducts() {
     int num = 0;
     for (CategoryProducts cp in _categoryProducts) {
-      if (cp.products.length > 0) {
+      if (cp.products!.length > 0) {
         num += 1;
       }
     }
@@ -1362,7 +1362,7 @@ class ShopState extends State<Shop>
                 });
               }
 
-              if (cp.products.length == 0) {
+              if (cp.products!.length == 0) {
                 return SizedBox.shrink();
               }
 
@@ -1403,7 +1403,7 @@ class ShopState extends State<Shop>
                                 ),
                               ),
                               new Visibility(
-                                  visible: cp.description.isNotEmpty,
+                                  visible: cp.description!.isNotEmpty,
                                   child: new Text(
                                     cp.description,
                                     overflow: TextOverflow.ellipsis,
@@ -1448,7 +1448,7 @@ class ShopState extends State<Shop>
                     ),
                   );
                 } else {
-                  if (cp.products.length < Constants.ORDERS_PER_PAGE) {
+                  if (cp.products!.length < Constants.ORDERS_PER_PAGE) {
                     col.children.add(
                       Container(
                         padding: EdgeInsets.all(12.0),
@@ -1620,7 +1620,7 @@ class ShopState extends State<Shop>
                 displayProductByCategoryClickIndicator =
                     S.of(context).end_of_the_list;
               } else {
-                if (moreCategoryProducts[0].products.length < Constants.ORDERS_PER_PAGE) {
+                if (moreCategoryProducts[0].products!.length < Constants.ORDERS_PER_PAGE) {
                   _productCurrentPage = 0;
                   displayProductByCategoryClickIndicator =
                       S.of(context).end_of_the_list;
@@ -1631,7 +1631,7 @@ class ShopState extends State<Shop>
                 CategoryProducts currentCp =
                 getCategoryProductByCategoryId(categoryId);
                 if (currentCp != null) {
-                  currentCp.products.addAll(moreCategoryProducts[0].products);
+                  currentCp.products!.addAll(moreCategoryProducts[0].products);
                 } else {
                   _productCurrentPage = 0;
                   displayProductByCategoryClickIndicator =
@@ -1653,16 +1653,16 @@ class ShopState extends State<Shop>
   }
 
   CartLineItem _newCartLineItem(
-      {int id,
-        double price,
-        Product product,
-        String name,
-        String description,
-        double quantity}) {
+      {int? id,
+        double? price,
+        Product? product,
+        String? name,
+        String? description,
+        double? quantity}) {
     CartLineItem lineItem = CartLineItem();
     lineItem.unitPrice = price;
     lineItem.product = product;
-    lineItem.name = product.name;
+    lineItem.name = product!.name;
     lineItem.description = description;
     lineItem.quantity = quantity;
     return lineItem;

lib/widgets/mobile/shopping_cart_bar.dart

@@ -35,21 +35,21 @@ class ShoppingCartBar extends StatefulWidget {
 }
 
 class ShoppingCartBarState extends State<ShoppingCartBar> {
-  CartInfo cartInfo;
+  late CartInfo cartInfo;
   double totalPrice = 0.0;
 
   @override
   Widget build(BuildContext context) {
     totalPrice = 0.0;
     cartInfo = Utils.getCartInfoByBusiness(store.state.cartInfos, widget.business);
-    if (cartInfo != null && cartInfo.businessInfo.id == widget.business.id) {
+    if (cartInfo != null && cartInfo.businessInfo!.id == widget.business.id) {
       totalPrice = cartInfo.getTotalPrice();
     }
 
     Widget cartContent;
 
-    if (cartInfo == null || (cartInfo.businessInfo.id != widget.business.id)
-        || (totalPrice == 0.0 && cartInfo.productList.length == 0)) {
+    if (cartInfo == null || (cartInfo.businessInfo!.id != widget.business.id)
+        || (totalPrice == 0.0 && cartInfo.productList!.length == 0)) {
       cartContent = Center(
         child: Container(
           padding: EdgeInsets.all(20.0),
@@ -92,8 +92,8 @@ class ShoppingCartBarState extends State<ShoppingCartBar> {
           },
         ),
       );
-      for (var i = 0; i < cartInfo.productList.length; i++) {
-        (cartContent as Column).children.add(cartLineItem(cartInfo.productList[i], i));
+      for (var i = 0; i < cartInfo.productList!.length; i++) {
+        (cartContent as Column).children.add(cartLineItem(cartInfo.productList![i], i));
       }
     }
 
@@ -134,7 +134,7 @@ class ShoppingCartBarState extends State<ShoppingCartBar> {
                           ],
                         ),
                         new Text(
-                          S.of(context).delivery_fee(widget.business.shippingFee.toStringAsFixed(2)),
+                          S.of(context).delivery_fee(widget.business.shippingFee!.toStringAsFixed(2)),
                           style: new TextStyle(
                             fontSize: 9.0,
                             color: Style.backgroundColor,
@@ -149,10 +149,10 @@ class ShoppingCartBarState extends State<ShoppingCartBar> {
                 child: GestureDetector(
                   child: Container(
                     padding: EdgeInsets.all(10.0),
-                    color: widget.business.minPrice - totalPrice >= 0 ? new Color(0xFF535356) : Colors.lightGreen,
+                    color: widget.business.minPrice! - totalPrice >= 0 ? new Color(0xFF535356) : Colors.lightGreen,
                     child: Center(
                       child: Text(
-                        widget.business.minPrice - totalPrice >= 0 ? S.of(context).order_more((widget.business.minPrice - totalPrice).toStringAsFixed(2)) : S.of(context).checkout,
+                        widget.business.minPrice! - totalPrice >= 0 ? S.of(context).order_more((widget.business.minPrice! - totalPrice).toStringAsFixed(2)) : S.of(context).checkout,
                         style: TextStyle(
                           fontSize: 14.0,
                           color: Style.backgroundColor,
@@ -160,7 +160,7 @@ class ShoppingCartBarState extends State<ShoppingCartBar> {
                       ),
                     ),
                   ),
-                  onTap: widget.business.minPrice >= totalPrice ? null : () {
+                  onTap: widget.business.minPrice! >= totalPrice ? null : () {
                     if (store.state.user != null) {
                       Routes.router.navigateTo(context, '/checkout/${widget.business.id}');
                     } else {
@@ -255,7 +255,7 @@ class ShoppingCartBarState extends State<ShoppingCartBar> {
           widget.hasPicture ? Container(
             padding: EdgeInsets.all(6.0),
             child: Util.showImage(
-              '${item.product.imagePath}',
+              '${item.product!.imagePath}',
               width: 80,
               height: 80,
               fit: BoxFit.cover,
@@ -300,7 +300,7 @@ class ShoppingCartBarState extends State<ShoppingCartBar> {
               children: <Widget>[
                 Container(
                   child: Text(
-                    '${item.totalPrice.toStringAsFixed(2)}',
+                    '${item.totalPrice!.toStringAsFixed(2)}',
                     style: TextStyle(
                       color: Colors.redAccent,
                       fontSize: 14.0,

tools/nullfix.py

@@ -0,0 +1,175 @@
+#!/usr/bin/env python3
+"""
+nullfix.py — dart analyze 驱动的空安全批量修复（保守、带语法损坏自检）。
+
+处理的规则（全部由 analyzer 位置驱动，逐轮迭代）：
+  1. unchecked_use_of_nullable_value  -> 在接收者后插 '!'（属性/方法/[]/运算符）
+  2. not_initialized_non_nullable_instance_field / _variable
+     -> 字段/变量改为可空（在类型后插 '?'），跳过 return/this./关键词行
+  3. missing_default_value_for_parameter
+     -> 参数改为可空（类型后插 '?'），跳过 field-formal this.x
+
+不处理（需语义判断）: argument_type_not_assignable / invalid_assignment
+  （这两类留给后续：多为 nullable 传给非空形参，常伴随 1/2 解决后自动减少）
+
+每轮结束检测 expected_token / missing_identifier（语法损坏），有则中止。
+
+用法: python3 tools/nullfix.py [file] [--max-rounds N]
+"""
+import re, subprocess, sys, os
+
+ROUNDS = 40
+args=[]
+i=0
+while i<len(sys.argv):
+    a=sys.argv[i]
+    if a=='--max-rounds': ROUNDS=int(sys.argv[i+1]); i+=2; continue
+    if not a.endswith('nullfix.py'): args.append(a)
+    i+=1
+TARGET = args[0] if args else None
+
+ERR = re.compile(r'\s+error\s+-\s+([\w/.\-]+):(\d+):(\d+)\s+-\s+(.*?)\s+-\s+([a-z_]+)\s*$')
+PROP = re.compile(r"The property '([^']+)'")
+METH = re.compile(r"The method '([^']+)'")
+OPR  = re.compile(r"The operator '([^']+)'")
+NAME = re.compile(r"'([^']+)'")
+KEYWORDS = {'return','throw','await','yield','break','continue','assert','new','const',
+            'final','var','late','switch','case','default','if','else','for','while',
+            'do','try','catch','finally','in','is','as','super','this'}
+
+def analyze():
+    out = subprocess.run(['dart','analyze','lib'], capture_output=True, text=True).stdout
+    errs=[]; corruption=0
+    for ln in out.splitlines():
+        if 'expected_token' in ln or 'missing_identifier' in ln:
+            corruption += 1
+        m = ERR.match(ln)
+        if m:
+            p,l,c,msg,r=m.groups(); errs.append((p,int(l),int(c),msg,r))
+    if TARGET:
+        t=TARGET.replace('lib/','')
+        errs=[e for e in errs if e[0].endswith(t)]
+    return errs, corruption, out
+
+def classify_use(msg):
+    m=PROP.search(msg)
+    if m: return (m.group(1),'prop')
+    m=METH.search(msg)
+    if m: return (None,'index') if m.group(1)=='[]' else (m.group(1),'meth')
+    m=OPR.search(msg)
+    if m: return (m.group(1),'op')
+    return None
+
+def find_name_col(line, name, col0):
+    """在 line 上找 name 的出现，返回最接近 col0 的起始 index；找不到 None。"""
+    best=None
+    for mm in re.finditer(r'(?<![\w])'+re.escape(name)+r'(?!\w)', line):
+        d=abs(mm.start()-col0)
+        if best is None or d<best[0]: best=(d,mm.start())
+    return best[1] if best else None
+
+def insert_bang(line, col0, name, kind):
+    if kind in ('prop','meth') and name:
+        pat = re.compile(r'(?<!!)\.' + re.escape(name) + r'\b')
+        best=None
+        for mm in pat.finditer(line):
+            d=abs(mm.start()-col0)
+            if best is None or d<best[0]: best=(d,mm)
+        if not best: return None
+        idx=best[1].start(); j=idx-1
+        if j<0: return None
+        if line[j]=='!': return None
+        if not (line[j].isalnum() or line[j] in '_)?]'): return None
+        return line[:idx]+'!'+line[idx:]
+    if kind=='index':
+        best=None
+        for i,ch in enumerate(line):
+            if ch=='[':
+                d=abs(i-col0)
+                if best is None or d<best[0]: best=(d,i)
+        if not best: return None
+        idx=best[1]; j=idx-1
+        if j<0 or line[j]=='!': return None
+        if line[j].isalnum() or line[j] in '_)?]': return line[:idx]+'!'+line[idx:]
+        return None
+    if kind=='op':
+        for mm in re.finditer(re.escape(name), line):
+            idx=mm.start(); j=idx-1
+            while j>=0 and line[j]==' ': j-=1
+            if j<0 or line[j]=='!': continue
+            if line[j].isalnum() or line[j] in '_)?]': return line[:j+1]+'!'+line[j+1:]
+        return None
+    return None
+
+def insert_late(line):
+    stripped=line.strip()
+    if not stripped or stripped.startswith('late '): return None
+    head=stripped.split(';')[0]
+    if '?' in head or '=' in head: return None  # 已可空/已初始化
+    indent=line[:len(line)-len(stripped)]
+    if stripped.startswith('static '): return indent+'static late '+stripped[len('static '):]
+    if stripped.startswith('external '): return indent+'external late '+stripped[len('external '):]
+    return indent+'late '+stripped
+
+def insert_nullable_before_name(line, name, col0):
+    """把 'Type name' 改为 'Type? name'。跳过 field-formal(this.)、关键词行。"""
+    stripped=line.strip()
+    first=stripped.split(' ')[0] if stripped else ''
+    if first.rstrip(')').rstrip('(') in KEYWORDS: return None
+    idx=find_name_col(line, name, col0)
+    if idx is None: return None
+    # name 前一个非空字符
+    j=idx-1
+    while j>=0 and line[j] in ' \t': j-=1
+    if j<0: return None
+    if line[j]=='.':  return None   # field-formal this.name
+    if line[j]=='?':  return None   # 已可空
+    # j 应是类型末尾（字母/>/)/]）
+    if not (line[j].isalnum() or line[j] in '_>]?)'): return None
+    return line[:j+1]+'?'+line[j+1:]
+
+def apply_round(errs):
+    changed=0; files={}
+    def get(path):
+        if path not in files:
+            files[path]=open('lib/'+path).read().split('\n')
+        return files[path]
+    def flush():
+        for p,ls in files.items():
+            open('lib/'+p,'w').write('\n'.join(ls))
+    for path,line,col,msg,rule in errs:
+        if not os.path.exists('lib/'+path): continue
+        L=get(path)
+        if line>len(L): continue
+        old=L[line-1]; new=old
+        if rule=='unchecked_use_of_nullable_value':
+            cls=classify_use(msg)
+            if cls: new=insert_bang(old, col-1, cls[0], cls[1])
+        elif rule=='missing_default_value_for_parameter':
+            nm=NAME.search(msg)
+            if nm: new=insert_nullable_before_name(old, nm.group(1), col-1)
+        elif rule in ('not_initialized_non_nullable_instance_field','not_initialized_non_nullable_variable'):
+            new=insert_late(old)
+        if new and new!=old:
+            L[line-1]=new; changed+=1
+    flush()
+    return changed
+
+rounds=0
+while rounds<ROUNDS:
+    errs,corruption,_=analyze()
+    if corruption:
+        print(f'!! 检测到 {corruption} 处语法损坏，中止。请 git diff 检查。'); sys.exit(2)
+    if not errs: print('无错误，完成。'); break
+    c=apply_round(errs)
+    rounds+=1
+    print(f'第 {rounds} 轮：修复 {c} 处（剩余 error {len(errs)}）')
+    if c==0:
+        print('本轮无新增修复，剩余需人工/IDE 处理：')
+        from collections import Counter
+        cnt=Counter(e[4] for e in errs)
+        for r,n in cnt.most_common(8): print(f'   {n:4d}  {r}')
+        break
+
+errs,corruption,_=analyze()
+print(f'\n=== 完成。剩余 error: {len(errs)} | 语法损坏: {corruption} ===')