backup.

lib/utils/double_back_to_close_app.dart

@@ -0,0 +1,98 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+
+/// Allows the user to close the app by double tapping the back-button.
+///
+/// You must specify a [SnackBar], so it can be shown when the user taps the
+/// back-button. Notice that the value you set for [SnackBar.duration] is going
+/// to be considered to decide whether the snack-bar is currently visible or
+/// not.
+///
+/// Since the back-button is an Android feature, this Widget is going to be
+/// nothing but the own [child] if the current platform is anything but Android.
+class DoubleBackToCloseApp extends StatefulWidget {
+  /// The [SnackBar] shown when the user taps the back-button.
+  final SnackBar snackBar;
+
+  /// The widget below this widget in the tree.
+  final Widget child;
+
+  /// Creates a widget that allows the user to close the app by double tapping
+  /// the back-button.
+  const DoubleBackToCloseApp({
+    Key key,
+    @required this.snackBar,
+    @required this.child,
+  })  : assert(snackBar != null),
+        assert(child != null),
+        super(key: key);
+
+  @override
+  _DoubleBackToCloseAppState createState() => _DoubleBackToCloseAppState();
+}
+
+class _DoubleBackToCloseAppState extends State<DoubleBackToCloseApp> {
+  /// The last time the user tapped Android's back-button.
+  DateTime _lastTimeBackButtonWasTapped;
+
+  /// Returns whether the current platform is Android.
+  bool get _isAndroid => Theme.of(context).platform == TargetPlatform.android;
+
+  /// Returns whether the [DoubleBackToCloseApp.snackBar] is currently visible.
+  ///
+  /// The snack-bar is going to be considered visible if the duration of the
+  /// snack-bar is greater than the difference from now to the
+  /// [_lastTimeBackButtonWasTapped].
+  ///
+  /// This is not quite accurate since the snack-bar could've been dismissed by
+  /// the user, so this algorithm needs to be improved, as described in #2.
+  bool get _isSnackBarVisible =>
+      (_lastTimeBackButtonWasTapped != null) &&
+          (widget.snackBar.duration >
+              DateTime.now().difference(_lastTimeBackButtonWasTapped));
+
+  /// Returns whether the next back navigation of this route will be handled
+  /// internally.
+  ///
+  /// Returns true when there's a widget that inserted an entry into the
+  /// 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;
+
+  @override
+  Widget build(BuildContext context) {
+    _ensureThatContextContainsScaffold();
+
+    if (_isAndroid) {
+      return WillPopScope(
+        onWillPop: _handleWillPop,
+        child: widget.child,
+      );
+    } else {
+      return widget.child;
+    }
+  }
+
+  /// Handles [WillPopScope.onWillPop].
+  Future<bool> _handleWillPop() async {
+    if (_isSnackBarVisible || _willHandlePopInternally) {
+      return true;
+    } else {
+      _lastTimeBackButtonWasTapped = DateTime.now();
+      // Scaffold.of(context).showSnackBar(widget.snackBar);
+      ScaffoldMessenger.of(context).showSnackBar(widget.snackBar);
+      return false;
+    }
+  }
+
+  /// Throws a [FlutterError] if this widget was not wrapped in a [Scaffold].
+  void _ensureThatContextContainsScaffold() {
+    if (Scaffold.maybeOf(context) == null) {
+      throw FlutterError(
+        '`DoubleBackToCloseApp` must be wrapped in a `Scaffold`.',
+      );
+    }
+  }
+}

lib/utils/http_util.dart

@@ -0,0 +1,370 @@
+
+
+import 'dart:async';
+import 'dart:convert';
+
+import 'package:crypto/crypto.dart';
+import 'package:dio/dio.dart';
+import '../store/store.dart';
+import 'utils.dart';
+import 'package:hive/hive.dart';
+import 'package:universal_io/io.dart';
+
+import '../constants.dart';
+
+typedef void PostCallback(Response response);
+
+String generateSignature(String string, {String key}) {
+  if (key == null) {
+    key = Constants.API_SECRET;
+  }
+  Hmac mac = new Hmac(sha256, utf8.encode(key));
+  Digest digest = mac.convert(utf8.encode(string + key));
+  String base64Mac = base64.encode(utf8.encode("$digest"));
+  return base64Mac;
+}
+
+class HttpUtil {
+  static String platformName = Utils.getPlatformName();
+
+  static final Map<String, String> headers = {
+    'Accept': 'application/json',
+//    'Content-Type': 'application/json',
+    'Http-Signature': '',
+//    'Http-Group-Id': Constants.GROUP_ID,
+    'Http-Business-Id': '0',
+    'Http-App-Key': '',
+    'Http-Contact-Authorization': '',
+    'Http-Device-Type': Platform.isIOS ? 'ios' : (Platform.isAndroid ? 'android' : 'web'),
+    'Http-Api-Branch': 'flutter',
+    'Http-Language-Code': store.state.locale.languageCode,
+  };
+
+  static Future<dynamic> httpGet(String url,
+      {
+        Map<String, dynamic> queryParameters,
+        int businessId = 0,
+        Function(int, int) receiveProgress,
+        bool returnError = false,
+        Map<String, String> additionalHeaders,
+      }) async {
+    Map<String, dynamic> localHeaders = json.decode(json.encode(headers));
+    if (additionalHeaders != null) {
+      localHeaders.addAll(additionalHeaders);
+    }
+
+    if (!url.startsWith('http')) {
+      localHeaders['Http-Signature'] = generateSignature(url);
+    }
+
+    localHeaders['Http-Business-Id'] = businessId.toString();
+    Box box = await Utils.getBox();
+    localHeaders['Http-Contact-Authorization'] = box.get(Constants.KEY_ACCESS_TOKEN, defaultValue: '');
+    localHeaders['Http-App-Key'] = platformName;
+    localHeaders['Http-Device-Type'] = platformName;
+    String requestUrl = Constants.BASE_API_URL + url;
+
+    if (url.startsWith('http')) {
+      requestUrl = url;
+    }
+
+    Utils.jsonPrettyPrint(queryParameters);
+
+    Dio dio = Dio();
+    try {
+      Response response = await dio.get(requestUrl,
+        queryParameters: queryParameters,
+        options: Options(
+          headers: localHeaders
+        ),
+        onReceiveProgress: receiveProgress,
+      ).timeout(const Duration(seconds: 30));
+
+      print('HttpGet success. Request: $requestUrl, Response: ${response.statusCode}, Headers: ${response.request.headers}');
+//      print(response.data);
+//      Utils.jsonPrettyPrint(response.data);
+
+      int statusCode = response.statusCode;
+      return response.data;
+    } on DioError catch(e) {
+      print('error $e');
+      if (returnError) {
+        return e;
+      }
+      throw e;
+    }
+  }
+
+  static Future<dynamic> httpPost(String url, PostCallback callback,
+      {
+        Map<String, dynamic> queryParameters,
+        int businessId = 0,
+        bool isFormData = false,
+        Map<String, String> additionalHeaders,
+        Map<String, dynamic> body,
+        Function(int, int) sendProgress,
+        Function(int, int) receiveProgress,
+        bool returnError = false,
+      }) async {
+
+    Map<String, dynamic> localHeaders = json.decode(json.encode(headers));
+    if (additionalHeaders != null) {
+      localHeaders.addAll(additionalHeaders);
+    }
+    if (!url.startsWith('http')) {
+      localHeaders['Http-Signature'] = generateSignature(url);
+    }
+    localHeaders['Http-Business-Id'] = businessId.toString();
+    Box box = await Utils.getBox();
+    localHeaders['Http-Contact-Authorization'] = box.get(Constants.KEY_ACCESS_TOKEN, defaultValue: '');
+    localHeaders['Http-App-Key'] = platformName;
+    localHeaders['Http-Device-Type'] = platformName;
+
+    String requestUrl = Constants.BASE_API_URL + url;
+    if (url.startsWith('http')) {
+      requestUrl = url;
+    }
+
+    // Don't print body will cause upload Multipart file failed
+    //Utils.jsonPrettyPrint(body);
+
+    Dio dio = Dio();
+    dio.interceptors.add(LogInterceptor());
+    try {
+      Response response = await dio.post(
+        requestUrl,
+        queryParameters: queryParameters == null ? {} : queryParameters,
+        data: isFormData ? FormData.fromMap(body) : json.encode(body),
+        options: Options(
+          headers: localHeaders,
+//          contentType: isFormData ? Headers.formUrlEncodedContentType : Headers.jsonContentType,
+        ),
+        onSendProgress: sendProgress,
+        onReceiveProgress: receiveProgress,
+      ).timeout(Duration(seconds: 30));
+
+      print('HttpPost Success. Request: ${response.request.uri}, Response: ${response.statusCode}, Headers: ${response.request.headers}');
+//      Utils.jsonPrettyPrint(response.data);
+
+      int statusCode = response.statusCode;
+      if (callback != null) {
+        callback(response);
+      }
+      return response.data;
+    } on DioError catch(e) {
+      if (e.response != null) {
+        print('HttpPost failed. Request: ${e.request.uri}, Headers: ${e.response.request.headers}');
+        try {
+          Utils.jsonPrettyPrint(e.response.data);
+        } catch (err) {
+          print(e.response.data);
+        }
+      }
+      if (returnError) {
+        return e;
+      }
+      throw e;
+    }
+  }
+
+  static Future<dynamic> httpPut(String url, PostCallback callback,
+      {
+        Map<String, dynamic> queryParameters,
+        int businessId = 0,
+        Map<String, String> additionalHeaders,
+        Map<String, dynamic> body,
+        Function(int, int) sendProgress,
+        Function(int, int) receiveProgress,
+        bool returnError = false,
+      }) async {
+
+    Map<String, dynamic> localHeaders = json.decode(json.encode(headers));
+    if (additionalHeaders != null) {
+      localHeaders.addAll(additionalHeaders);
+    }
+
+    if (!url.startsWith('http')) {
+      localHeaders['Http-Signature'] = generateSignature(url);
+    }
+
+    localHeaders['Http-Business-Id'] = businessId.toString();
+    Box box = await Utils.getBox();
+    localHeaders['Http-Contact-Authorization'] = box.get(Constants.KEY_ACCESS_TOKEN, defaultValue: '');
+    localHeaders['Http-App-Key'] = platformName;
+    localHeaders['Http-Device-Type'] = platformName;
+
+    localHeaders['Content-Type'] = Headers.jsonContentType;
+
+    String requestUrl = Constants.BASE_API_URL + url;
+
+    if (url.startsWith('http')) {
+      requestUrl = url;
+    }
+
+    Dio dio = Dio();
+    try {
+      Response response = await dio.put(
+        requestUrl,
+        queryParameters: queryParameters == null ? {} : queryParameters,
+        data: json.encode(body),
+        options: Options(
+          headers: localHeaders,
+        ),
+        onSendProgress: sendProgress,
+        onReceiveProgress: receiveProgress,
+      ).timeout(Duration(seconds: 30));
+
+      print('HttpPost Success. Request: ${response.request.uri}, Response: ${response.statusCode}, Headers: ${response.request.headers}');
+//      Utils.jsonPrettyPrint(response.data);
+
+      int statusCode = response.statusCode;
+      if (callback != null) {
+        callback(response);
+      }
+      return response.data;
+    } on DioError catch(e) {
+      print('HttpPost failed. Request: ${e.request.uri}');
+      if (e.response != null) {
+        Utils.jsonPrettyPrint(e.response.data);
+      }
+      if (returnError) {
+        return e;
+      }
+      throw e;
+    }
+  }
+
+  static Future<dynamic> httpPatch(String url, PostCallback callback,
+      {
+        Map<String, dynamic> queryParameters,
+        int businessId = 0,
+        Map<String, String> additionalHeaders,
+        Map<String, dynamic> body,
+        Function(int, int) sendProgress,
+        Function(int, int) receiveProgress,
+        bool returnError = false,
+      }) async {
+
+    Map<String, dynamic> localHeaders = json.decode(json.encode(headers));
+    if (additionalHeaders != null) {
+      localHeaders.addAll(additionalHeaders);
+    }
+
+    if (!url.startsWith('http')) {
+      localHeaders['Http-Signature'] = generateSignature(url);
+    }
+
+    localHeaders['Http-Business-Id'] = businessId.toString();
+    Box box = await Utils.getBox();
+    localHeaders['Http-Contact-Authorization'] = box.get(Constants.KEY_ACCESS_TOKEN, defaultValue: '');
+    localHeaders['Http-App-Key'] = platformName;
+    localHeaders['Http-Device-Type'] = platformName;
+
+    localHeaders['Content-Type'] = Headers.jsonContentType;
+
+    String requestUrl = Constants.BASE_API_URL + url;
+
+    if (url.startsWith('http')) {
+      requestUrl = url;
+    }
+
+    Utils.jsonPrettyPrint(body);
+
+    Dio dio = Dio();
+    try {
+      Response response = await dio.patch(
+        requestUrl,
+        queryParameters: queryParameters == null ? {} : queryParameters,
+        data: json.encode(body),
+        options: Options(
+          headers: localHeaders,
+        ),
+        onSendProgress: sendProgress,
+        onReceiveProgress: receiveProgress,
+      ).timeout(Duration(seconds: 30));
+
+      print('HttpPost Success. Request: ${response.request.uri}, Response: ${response.statusCode}, Headers: ${response.request.headers}');
+//      Utils.jsonPrettyPrint(response.data);
+
+      int statusCode = response.statusCode;
+      if (callback != null) {
+        callback(response);
+      }
+      return response.data;
+    } on DioError catch(e) {
+      print('HttpPost failed. Request: ${e.request.uri}');
+      if (e.response != null) {
+        Utils.jsonPrettyPrint(e.response.data);
+      }
+      if (returnError) {
+        return e;
+      }
+      throw e;
+    }
+  }
+
+  static Future<dynamic> httpDelete(String url, PostCallback callback,
+      {
+        Map<String, dynamic> queryParameters,
+        int businessId = 0,
+        Map<String, String> additionalHeaders,
+        Map<String, dynamic> body,
+        bool returnError = false,
+      }) async {
+
+    Map<String, dynamic> localHeaders = json.decode(json.encode(headers));
+    if (additionalHeaders != null) {
+      localHeaders.addAll(additionalHeaders);
+    }
+
+    if (!url.startsWith('http')) {
+      localHeaders['Http-Signature'] = generateSignature(url);
+    }
+
+    localHeaders['Http-Business-Id'] = businessId.toString();
+    Box box = await Utils.getBox();
+    localHeaders['Http-Contact-Authorization'] = box.get(Constants.KEY_ACCESS_TOKEN, defaultValue: '');
+    localHeaders['Http-App-Key'] = platformName;
+    localHeaders['Http-Device-Type'] = platformName;
+
+    localHeaders['Content-Type'] = Headers.jsonContentType;
+
+    String requestUrl = Constants.BASE_API_URL + url;
+
+    if (url.startsWith('http')) {
+      requestUrl = url;
+    }
+
+    Utils.jsonPrettyPrint(body);
+
+    Dio dio = Dio();
+    try {
+      Response response = await dio.delete(
+        requestUrl,
+        queryParameters: queryParameters == null ? {} : queryParameters,
+        data: json.encode(body),
+        options: Options(
+          headers: localHeaders,
+        ),
+      ).timeout(Duration(seconds: 30));
+
+      print('HttpPost Success. Request: ${response.request.uri}, Response: ${response.statusCode}, Headers: ${response.request.headers}');
+//      Utils.jsonPrettyPrint(response.data);
+
+      int statusCode = response.statusCode;
+      if (callback != null) {
+        callback(response);
+      }
+      return response.data;
+    } on DioError catch(e) {
+      print('HttpPost failed. Request: ${e.request.uri}');
+      if (e.response != null) {
+        Utils.jsonPrettyPrint(e.response.data);
+      }
+      if(returnError) {
+        return e;
+      }
+      throw e;
+    }
+  }
+}

lib/utils/util_io.dart

@@ -0,0 +1,46 @@
+
+import 'package:cached_network_image/cached_network_image.dart';
+import 'package:flutter/material.dart';
+import '../routes.dart';
+import 'utils.dart';
+import 'package:hive/hive.dart';
+import 'package:path_provider/path_provider.dart';
+
+class Util {
+  static Future<Box> getBox() async {
+    final dir = await getApplicationDocumentsDirectory();
+    Hive.init(dir.path);
+    Box box = await Hive.openBox('app_data');
+    return box;
+  }
+
+  static Widget showImage(String imageUrl, {double width, double height,
+    BoxFit fit, Widget Function(BuildContext, String, dynamic) errorWidget}) {
+    if (imageUrl == null || imageUrl.isEmpty) {
+      return Container(
+        width: width,
+        height: height,
+        child: Text(''),
+      );
+    }
+    return CachedNetworkImage(
+      imageUrl: imageUrl,
+      width: width,
+      height: width,
+      fit: fit,
+      placeholder: (context, url) => Utils.imageLoadingIndicator(),
+      errorWidget: errorWidget != null ? errorWidget : (context, url, error) {
+        return Image.asset(
+          'assets/images/not_found.png',
+          width: width,
+          height: height,
+          fit: fit,
+        );
+      },
+    );
+  }
+
+  static void openWebUrl(BuildContext context, String link) {
+    Routes.router.navigateTo(context, '/webview/$link');
+  }
+}

lib/utils/util_web.dart

@@ -0,0 +1,52 @@
+
+import 'package:flutter/material.dart';
+import 'package:url_launcher/url_launcher.dart';
+import 'utils.dart';
+import 'package:hive/hive.dart';
+import 'package:hive_flutter/hive_flutter.dart';
+
+class Util {
+
+  static Future<Box> getBox() async {
+    Hive.initFlutter();
+    Box box = await Hive.openBox('wisetronic_app_data');
+    return box;
+  }
+
+  static Widget showImage(String imageUrl, {double width, double height,
+    BoxFit fit, Widget Function(BuildContext, String, dynamic) errorWidget}) {
+    return Image.network(imageUrl,
+      fit: fit,
+      width: width,
+      height: height,
+      cacheWidth: width != null ? width.round() : null,
+      cacheHeight: height != null ? height.round() : null,
+      loadingBuilder: (BuildContext context, Widget child, ImageChunkEvent loadingProgress) {
+        if (loadingProgress == null) return child;
+        return Center(
+          child: Utils.imageLoadingIndicator(),
+        );
+      },
+      errorBuilder: (BuildContext context, Object object, StackTrace stackTrace) {
+        if (errorWidget != null) {
+          return errorWidget(context, null, null);
+        }
+        return Image.asset(
+          'assets/images/not_found.png',
+          width: width,
+          height: height,
+          fit: fit,
+        );
+      },
+    );
+  }
+
+  static void openWebUrl(BuildContext context, String link) async {
+    var url = 'https://${link}';
+    if (await canLaunch(url)) {
+      await launch('$url');
+    } else {
+      print('Could not launch $url');
+    }
+  }
+}

lib/utils/utils.dart

@@ -0,0 +1,277 @@
+
+import 'dart:convert';
+
+import 'package:dio/dio.dart';
+import 'package:flutter/cupertino.dart';
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_spinkit/flutter_spinkit.dart';
+import 'package:flutter_wisetronic/generated/l10n.dart';
+import 'package:fluttertoast/fluttertoast.dart';
+import 'package:hive/hive.dart';
+import 'package:intl/intl.dart';
+import 'package:url_launcher/url_launcher.dart';
+import 'package:universal_io/io.dart';
+import 'util_web.dart' if (dart.library.io) 'util_io.dart';
+
+import '../routes.dart';
+import 'http_util.dart';
+
+typedef void OnSuccess(Response response);
+typedef void OnError(dynamic error);
+typedef void OnComplete(dynamic data);
+
+typedef void OnOk();
+
+class Utils {
+
+  static bool equalsIgnoreCase(String a, String b) =>
+      (a == null && b == null) ||
+          (a != null && b != null && a.toLowerCase() == b.toLowerCase());
+
+  static int selectionsContains(Map<String, dynamic> selections, String key, String name) {
+    if (selections.containsKey(key.toUpperCase())) {
+      for (var i = 0; i < (selections[key.toUpperCase()] as List).length; i++) {
+        Map<String, dynamic> item = (selections[key.toUpperCase()] as List)[i];
+        if (Utils.equalsIgnoreCase(item['name'], name)) {
+          return i;
+        }
+      }
+    }
+    return -1;
+  }
+
+  static List<String> getSelectedAttributeValue(Map<String, dynamic> selections, String key) {
+    List<String> valueArr = [];
+    if (selections.containsKey(key.toUpperCase())) {
+      for (var i = 0; i < (selections[key.toUpperCase()] as List).length; i++) {
+        valueArr.add((selections[key.toUpperCase()][i]['name'] as String).toLowerCase());
+      }
+    }
+    return valueArr;
+  }
+
+  static bool selectionsNotEmptyAt(Map<String, dynamic> selections, String key) {
+    if (selections.containsKey(key.toUpperCase()) && (selections[key.toUpperCase()] as List).length > 0) {
+      return true;
+    }
+    return false;
+  }
+
+  static Map<String, dynamic> stringToJson(String string) {
+    if (string == null || string.isEmpty) {
+      return null;
+    }
+    return json.decode(string);
+  }
+
+  static void jsonPrettyPrint(Map<String, dynamic> map) {
+    JsonEncoder encoder = new JsonEncoder.withIndent('    ');
+    String prettyPrint = encoder.convert(map);
+    debugPrint(prettyPrint);
+  }
+
+  static launchURL(String url) async {
+    if (await canLaunch(url)) {
+      await launch(url);
+    } else {
+      throw 'Could not launch $url';
+    }
+  }
+
+  static String getPlatformName() {
+    String platformName = '';
+    if (kIsWeb) {
+      platformName = 'web';
+    } else if (Platform.isAndroid) {
+      platformName = 'android';
+    } else if (Platform.isIOS) {
+      platformName = 'ios';
+    }
+    return platformName;
+  }
+
+  static Future<Box> getBox() async {
+    return Util.getBox();
+  }
+
+  static Widget imageLoadingIndicator() {
+    return SizedBox(
+      width: 30,
+      height: 30,
+      child: Container(
+        child: CupertinoActivityIndicator(),
+        color: Colors.transparent,
+      ),
+    );
+  }
+
+  static String safePhoneNumber(String phone) {
+    if (phone.length < 8) {
+      return phone;
+    }
+    String start = phone.substring(0, 3);
+    String end = phone.substring(phone.length - 3);
+    return '${start}****${end}';
+  }
+
+  static String safeString(String string) {
+    if (string == null || string.length == 0) {
+      return '';
+    }
+    String start = string.substring(0, 1);
+    String end = string.substring(string.length - 1);
+    return '${start}****${end}';
+  }
+
+  static String smartRound(double amount, int decimalPlace) {
+    double a = double.parse(amount.toStringAsFixed(decimalPlace));
+    double b = double.parse(amount.toStringAsFixed(0));
+    if (a - b == 0) {
+      return amount.toStringAsFixed(0);
+    }
+    return amount.toStringAsFixed(decimalPlace);
+  }
+
+  static void createOrUpdateStripePaymentMethod(
+      String paymentMethodId,
+      String cardBrand,
+      String paymentMethodType,
+      String cardCountry,
+      int cardExpMonth,
+      int cardExpYear,
+      String cardFunding,
+      String cardLast4,
+    ) {
+    HttpUtil.httpPost('v1/create-update-stripe-payment-method', (response) {
+      if (response.statusCode == 200) {
+        print('create or update customer stripe payment method success. ${response.data}');
+      }
+    },
+      body: {
+        'payment_method_id': paymentMethodId,
+        'card_brand': cardBrand,
+        'payment_method_type': paymentMethodType,
+        'card_country': cardCountry,
+        'card_exp_month': cardExpMonth,
+        'card_exp_year': cardExpYear,
+        'card_funding': cardFunding,
+        'card_last4': cardLast4,
+      },
+      isFormData: true,
+    ).catchError((error) {
+      print('Error: ${error}');
+    });
+  }
+
+  static showSubmitDialog(BuildContext context) {
+    showDialog(
+      context: context,
+      barrierDismissible: false,
+      builder: (BuildContext context) {
+        return AlertDialog(
+          content: WillPopScope(
+              child: Container(
+                width: 300.0,
+                height: 150.0,
+                child: Center(
+                  child: Column(
+                    mainAxisAlignment: MainAxisAlignment.center,
+                    crossAxisAlignment: CrossAxisAlignment.center,
+                    children: <Widget>[
+                      SpinKitThreeBounce(
+                        color: Colors.lightBlueAccent,
+                        size: 30.0,
+                      ),
+                      Text(
+                        S.of(context).submitting,
+                      ),
+                    ],
+                  ),
+                ),
+              ),
+              onWillPop: () async {
+                Fluttertoast.showToast(
+                    msg: S.of(context).submitting_please_wait,
+                    toastLength: Toast.LENGTH_SHORT,
+                    gravity: ToastGravity.CENTER,
+                    backgroundColor: Colors.red,
+                    textColor: Colors.white
+                );
+                return false;
+              }
+          ),
+        );
+      },
+    );
+  }
+
+  static showLoadingDialog(BuildContext context, {String message}) {
+    showDialog(
+      context: context,
+      barrierDismissible: false,
+      builder: (BuildContext context) {
+        return AlertDialog(
+          content: WillPopScope(
+              child: Container(
+                width: 80.0,
+                height: 80.0,
+                child: Center(
+                  child: Column(
+                    mainAxisAlignment: MainAxisAlignment.center,
+                    crossAxisAlignment: CrossAxisAlignment.center,
+                    children: <Widget>[
+                      SpinKitThreeBounce(
+                        color: Colors.lightBlueAccent,
+                        size: 30.0,
+                      ),
+                      Text(
+                        message != null ? message : S.of(context).recalculating,
+                      ),
+                    ],
+                  ),
+                ),
+              ),
+              onWillPop: () async {
+                Fluttertoast.showToast(
+                    msg: S.of(context).loading_please_wait,
+                    toastLength: Toast.LENGTH_SHORT,
+                    gravity: ToastGravity.CENTER,
+                    backgroundColor: Colors.red,
+                    textColor: Colors.white
+                );
+                return false;
+              }
+          ),
+        );
+      },
+    );
+  }
+
+  static getTitleFromBody(String body) {
+    if (body.length <= 30) {
+      return body;
+    }
+    return body.substring(0, 29);
+  }
+
+  static void getMiniLink(String realLink, OnSuccess onSuccess, OnError onError) {
+    HttpUtil.httpPost('get-minilink/', (response) {
+      onSuccess(response);
+    },
+      body: {
+        'link': realLink
+      },
+      isFormData: true,
+    ).catchError((error) {
+      onError(error);
+    });
+  }
+}
+
+class RuntimeError extends Error{
+  final int code;
+  final String message;
+  RuntimeError(this.message, {this.code});
+  String toString() => "Runtime Error: $message";
+}