phase3(foundation): http_util dio5 migration + null-safe models

- http_util.dart: dio4->5 (DioException, nullable params, drop unused statusCode,
  null-safe e.response!.data), countryCode ?? ''
- models/* (39 files): make all instance fields nullable (fromJson initializer-list
  pattern forces nullable); fix internal method usages (cart_info/cart_line_item/
  order/shipping_rate) with !/??
- models/ now passes dart analyze with 0 errors

Widget-level null-safety + remaining utils/store continue in next batch.

lib/models/Subproduct.dart

@@ -4,9 +4,9 @@ import 'dart:convert';
 import 'package:flutter_wisetronic/models/product_attribute.dart';
 
 class Subproduct {
-  int id;
-  SimpleProduct product;
-  double quantity;
+  int? id;
+  SimpleProduct? product;
+  double? quantity;
 
   Subproduct.fromJson(Map<String, dynamic> json) :
       id = json['id'],
@@ -26,15 +26,15 @@ class Subproduct {
 }
 
 class SimpleProduct {
-  int id;
-  String name;
-  String sku;
-  double price;
-  String description;
-  String image;
-  List<ProductAttribute> productAttributes;
-  double customerLastPrice;
-  String extraData;
+  int? id;
+  String? name;
+  String? sku;
+  double? price;
+  String? description;
+  String? image;
+  List<ProductAttribute>? productAttributes;
+  double? customerLastPrice;
+  String? extraData;
 
   SimpleProduct.fromJson(Map<String, dynamic> json) :
       id = json['id'],

lib/models/address.dart

@@ -1,21 +1,21 @@
 import 'dart:convert';
 
 class Address {
-  int id;
-  String addressLine1;
-  String addressLine2;
-  String city;
-  String state;
-  String country;
-  String zip;
-  String phone;
-  String fax;
-  String email;
-  String contactName;
-  int gender;
-  String lat;
-  String lng;
-  String fullAddress;
+  int? id;
+  String? addressLine1;
+  String? addressLine2;
+  String? city;
+  String? state;
+  String? country;
+  String? zip;
+  String? phone;
+  String? fax;
+  String? email;
+  String? contactName;
+  int? gender;
+  String? lat;
+  String? lng;
+  String? fullAddress;
 
   Address.fromJson(Map<String, dynamic> json)
     : id = json['id'],

lib/models/blog.dart

@@ -2,8 +2,8 @@
 import 'dart:convert';
 
 class Section {
-  int id;
-  String name;
+  int? id;
+  String? name;
 
   Section.fromJson(Map<String, dynamic> json) :
       id = json['id'],
@@ -21,14 +21,14 @@ class Section {
 }
 
 class Blog {
-  int id;
-  String title;
-  String body;
-  String createdAt;
-  String thumbUrl;
-  String imageUrl;
-  String videoUrl;
-  Section section;
+  int? id;
+  String? title;
+  String? body;
+  String? createdAt;
+  String? thumbUrl;
+  String? imageUrl;
+  String? videoUrl;
+  Section? section;
 
   Blog.fromJson(Map<String, dynamic> json) :
       id = json['id'],

lib/models/booking_date_time.dart

@@ -4,10 +4,10 @@ import 'dart:convert';
 import 'booking_time.dart';
 
 class BookingDateTime {
-  String viewDate;
-  int unixTime;
-  String sendTimeTip;
-  List<BookingTime> bookTimes;
+  String? viewDate;
+  int? unixTime;
+  String? sendTimeTip;
+  List<BookingTime>? bookTimes;
 
   BookingDateTime(this.viewDate, this.unixTime, this.sendTimeTip, this.bookTimes);
 

lib/models/booking_time.dart

@@ -2,9 +2,9 @@
 import 'dart:convert';
 
 class BookingTime {
-  String viewTime;
-  int unixTime;
-  String sendTimeTip;
+  String? viewTime;
+  int? unixTime;
+  String? sendTimeTip;
 
   BookingTime(this.viewTime, this.unixTime, this.sendTimeTip);
 

lib/models/business.dart

@@ -8,7 +8,7 @@ import 'product.dart';
 import 'waiting_line.dart';
 
 class QuickInput {
-  String value;
+  String? value;
   QuickInput.fromJson(Map<String, dynamic> json)
     : value = json['value'];
 
@@ -23,48 +23,48 @@ class QuickInput {
 }
 
 class Business {
-  int id;
-  String name;
-  String phone;
-  Address address;
-  String fullAddress;
-  String picUrl;
-  int status;
-  List<BusinessTime> openingTime;
-  double shippingFee;
-  double packageFee;
-  double minPrice;
-  int shippingTime;
-  int monthSales;
-  String bulletin;
-  int category;
-  bool isLike;
-  String description;
-  String policy;
-  String bannerImageUrl;
-  int todayOpen;
-  int todayClose;
-  bool showMonthlySold;
-  List<ImageUrl> slideImages;
-  List<Product> promoProducts;
-  String paypalEmail;
-  bool deliveryCanadaPost;
-  bool deliveryStoreDelivery;
-  bool deliveryPickup;
-  String currency;
-  List<WaitingLine> waitingLine;
-  bool enableWaitingLine;
-  double pointsToCreditsConversionRate;
-  String chaseXLogin;
-  String chaseTransactionKey;
-  String chaseResponseKey;
-  DistanceInfo distanceInfo;
-  int commentsCount;
-  bool forceClose;
-  bool isPublic;
-  double referrerCoupon;
-  bool instanceDelivery;
-  List<QuickInput> quickInputs;
+  int? id;
+  String? name;
+  String? phone;
+  Address? address;
+  String? fullAddress;
+  String? picUrl;
+  int? status;
+  List<BusinessTime>? openingTime;
+  double? shippingFee;
+  double? packageFee;
+  double? minPrice;
+  int? shippingTime;
+  int? monthSales;
+  String? bulletin;
+  int? category;
+  bool? isLike;
+  String? description;
+  String? policy;
+  String? bannerImageUrl;
+  int? todayOpen;
+  int? todayClose;
+  bool? showMonthlySold;
+  List<ImageUrl>? slideImages;
+  List<Product>? promoProducts;
+  String? paypalEmail;
+  bool? deliveryCanadaPost;
+  bool? deliveryStoreDelivery;
+  bool? deliveryPickup;
+  String? currency;
+  List<WaitingLine>? waitingLine;
+  bool? enableWaitingLine;
+  double? pointsToCreditsConversionRate;
+  String? chaseXLogin;
+  String? chaseTransactionKey;
+  String? chaseResponseKey;
+  DistanceInfo? distanceInfo;
+  int? commentsCount;
+  bool? forceClose;
+  bool? isPublic;
+  double? referrerCoupon;
+  bool? instanceDelivery;
+  List<QuickInput>? quickInputs;
 
   Business.fromJson(Map<String, dynamic> json)
     : id = json['id'],

lib/models/business_time.dart

@@ -1,8 +1,8 @@
 import 'dart:convert';
 
 class BusinessTime {
-  String openTime;
-  String closeTime;
+  String? openTime;
+  String? closeTime;
 
   BusinessTime.fromJson(Map<String, dynamic> json)
     : openTime = json['open_time'],

lib/models/cart_info.dart

@@ -7,18 +7,18 @@ import 'cart_line_item.dart';
 import 'extra_fee.dart';
 
 class CartInfo {
-  int id;
-  double originPrice;
-  double discountPrice;
-  double totalPrice;
-  Business businessInfo;
-  List<CartLineItem> productList;
-  List<ExtraFee> extraFeeList;
-  List<ExtraFee> discountList;
-  int deliveryMethod;
-  String shippingMethod;
-  double amountPaid;
-  String extraData;
+  int? id;
+  double? originPrice;
+  double? discountPrice;
+  double? totalPrice;
+  Business? businessInfo;
+  List<CartLineItem>? productList;
+  List<ExtraFee>? extraFeeList;
+  List<ExtraFee>? discountList;
+  int? deliveryMethod;
+  String? shippingMethod;
+  double? amountPaid;
+  String? extraData;
 
   CartInfo.fromJson(Map<String, dynamic> json)
     : id = json['id'],
@@ -53,7 +53,7 @@ class CartInfo {
     if (productList == null) {
       productList = [item];
     } else {
-      productList.add(item);
+      productList!.add(item);
     }
 
   }
@@ -74,19 +74,19 @@ class CartInfo {
     originPrice = 0.0;
     discountPrice = 0.0;
     totalPrice = 0.0;
-    for (var i = 0; i < productList.length; i++) {
-      newTotal += productList[i].getTotalPrice();
+    for (var i = 0; i < (productList?.length ?? 0); i++) {
+      newTotal += productList![i].getTotalPrice();
     }
     originPrice = newTotal;
     totalPrice = newTotal;
-    return totalPrice;
+    return totalPrice ?? 0.0;
   }
 
   int getProductListTotalQuantity() {
     int qty = 0;
-    if (productList != null && productList.length > 0) {
-      for (var i = 0; i < productList.length; i++) {
-        qty += productList[i].quantity.round();
+    if (productList != null && productList!.length > 0) {
+      for (var i = 0; i < productList!.length; i++) {
+        qty += (productList![i].quantity ?? 0).round();
       }
     }
     return qty;

lib/models/cart_line_item.dart

@@ -6,15 +6,15 @@ import 'package:uuid/uuid.dart';
 import 'product.dart';
 
 class CartLineItem {
-  int id;
-  double unitPrice;
-  double totalPrice;
-  Product product;
-  String name;
-  String description;
-  double quantity;
-  String uuid;
-  String parentUuid;
+  int? id;
+  double? unitPrice;
+  double? totalPrice;
+  Product? product;
+  String? name;
+  String? description;
+  double? quantity;
+  String? uuid;
+  String? parentUuid;
 
   CartLineItem() {
     uuid = Uuid().v4();
@@ -48,7 +48,7 @@ class CartLineItem {
   }
 
   double getTotalPrice() {
-    totalPrice = unitPrice * quantity;
-    return totalPrice;
+    totalPrice = (unitPrice ?? 0.0) * (quantity ?? 0);
+    return totalPrice ?? 0.0;
   }
 }

lib/models/category.dart

@@ -2,8 +2,8 @@
 import 'dart:convert';
 
 class Category {
-  int id;
-  String name;
+  int? id;
+  String? name;
 
   Category.fromJson(Map<String, dynamic> json)
     : id = json['id'],

lib/models/category_products.dart

@@ -4,12 +4,12 @@ import 'dart:convert';
 import 'product.dart';
 
 class CategoryProducts {
-  int id;
-  int businessId;
-  String name;
-  String description;
-  String iconUrl;
-  List<Product> products;
+  int? id;
+  int? businessId;
+  String? name;
+  String? description;
+  String? iconUrl;
+  List<Product>? products;
 
   CategoryProducts.fromJson(Map<String, dynamic> json)
     : id = json['id'],

lib/models/comment.dart

@@ -4,15 +4,15 @@ import 'dart:convert';
 import 'product_image.dart';
 
 class Comment {
-  int id;
-  String contact;
-  String content;
-  int rating;
-  List<ProductImage> images;
-  String createdAt;
-  int thumbUp;
-  int thumbDown;
-  String replyFromStore;
+  int? id;
+  String? contact;
+  String? content;
+  int? rating;
+  List<ProductImage>? images;
+  String? createdAt;
+  int? thumbUp;
+  int? thumbDown;
+  String? replyFromStore;
 
   Comment.fromJson(Map<String, dynamic> json) :
       id = json['id'],

lib/models/coupon.dart

@@ -4,14 +4,14 @@ import 'dart:convert';
 import 'business.dart';
 
 class Coupon {
-  int id;
-  String code;
-  String description;
-  String expirationDate;
-  double minAmount;
-  Business store;
-  double valueAmount;
-  bool isPercentage;
+  int? id;
+  String? code;
+  String? description;
+  String? expirationDate;
+  double? minAmount;
+  Business? store;
+  double? valueAmount;
+  bool? isPercentage;
 
   Coupon.fromJson(Map<String, dynamic> json)
     : id = json['id'],

lib/models/distance_info.dart

@@ -4,9 +4,9 @@ import 'dart:convert';
 import 'text_value.dart';
 
 class DistanceInfo {
-  TextValue duration;
-  TextValue distance;
-  String status;
+  TextValue? duration;
+  TextValue? distance;
+  String? status;
 
   DistanceInfo.fromJson(Map<String, dynamic> json)
     : duration = json['duration'] != null ? TextValue.fromJson(json['duration']) : null,

lib/models/error_message.dart

@@ -2,8 +2,8 @@
 import 'dart:convert';
 
 class ErrorMessage {
-  String code;
-  String string;
+  String? code;
+  String? string;
 
   ErrorMessage.fromJson(Map<String, dynamic> json)
     : code = json['code'],

lib/models/extra_fee.dart

@@ -3,11 +3,11 @@
 import 'dart:convert';
 
 class ExtraFee {
-  int id;
-  String name;
-  String description;
-  double rate;
-  double price;
+  int? id;
+  String? name;
+  String? description;
+  double? rate;
+  double? price;
 
   ExtraFee.fromJson(Map<String, dynamic> json)
     : id = json['id'],

lib/models/fulfillment.dart

@@ -2,11 +2,11 @@
 import 'dart:convert';
 
 class Fulfillment {
-  int id;
-  String shippingMethod;
-  String trackingNumber;
-  String note;
-  String createdAt;
+  int? id;
+  String? shippingMethod;
+  String? trackingNumber;
+  String? note;
+  String? createdAt;
 
   Fulfillment.fromJson(Map<String, dynamic> json) :
       id = json['id'],

lib/models/gallery.dart

@@ -2,9 +2,9 @@
 import 'dart:convert';
 
 class Gallery {
-  int id;
-  String image;
-  String linkUrl;
+  int? id;
+  String? image;
+  String? linkUrl;
 
   Gallery.fromJson(Map<String, dynamic> json)
       : id = json['id'],

lib/models/group.dart

@@ -3,8 +3,8 @@
 import 'dart:convert';
 
 class Group {
-  int id;
-  String name;
+  int? id;
+  String? name;
 
   Group.fromJson(Map<String, dynamic> json) :
       id = json['id'],

lib/models/image_url.dart

@@ -1,8 +1,8 @@
 import 'dart:convert';
 
 class ImageUrl {
-  int id;
-  String imageUrl;
+  int? id;
+  String? imageUrl;
 
   ImageUrl.fromJson(Map<String, dynamic> json)
     : id = json['id'],

lib/models/key_value.dart

@@ -1,7 +1,7 @@
 
 class KeyValue {
-  String name;
-  dynamic value;
+  String? name;
+  dynamic? value;
 
   KeyValue(this.name, this.value);
 

lib/models/located_address.dart

@@ -1,17 +1,17 @@
 import 'dart:convert';
 
 class LocatedAddress {
-  int storeId;
-  double latitude;
-  double longitude;
-  String streetNumber;
-  String streetName;
-  String city;
-  String locality;
-  String province;
-  String country;
-  String postalCode;
-  String formattedAddress;
+  int? storeId;
+  double? latitude;
+  double? longitude;
+  String? streetNumber;
+  String? streetName;
+  String? city;
+  String? locality;
+  String? province;
+  String? country;
+  String? postalCode;
+  String? formattedAddress;
 
   LocatedAddress.fromJson(Map<String, dynamic> json)
     : storeId = json['store_id'],

lib/models/order.dart

@@ -11,33 +11,33 @@ import 'fulfillment.dart';
 import 'user_position.dart';
 
 class Order {
-  int id;
-  int userId;
-  int businessId;
-  Business businessInfo;
-  CartInfo cartInfo;
-  int status;
-  double originPrice;
-  double discountPrice;
-  double totalPrice;
-  String consignee;
-  String phone;
-  String address;
-  Address shippingAddress;
-  int payMethod;
-  String remark;
-  String orderNum;
-  int bookedAt;
-  int createdAt;
-  String shippingMethod;
+  int? id;
+  int? userId;
+  int? businessId;
+  Business? businessInfo;
+  CartInfo? cartInfo;
+  int? status;
+  double? originPrice;
+  double? discountPrice;
+  double? totalPrice;
+  String? consignee;
+  String? phone;
+  String? address;
+  Address? shippingAddress;
+  int? payMethod;
+  String? remark;
+  String? orderNum;
+  int? bookedAt;
+  int? createdAt;
+  String? shippingMethod;
   String paymentStatus; // UNPAID, PAID, PARTIALPAID
-  double amountPaid;
-  List<Fulfillment> fulfillments;
-  String extraData;
-  bool hasComment;
-  double fee;
-  UserPosition shipperPosition;
-  DistanceInfo deliveryDistance;
+  double? amountPaid;
+  List<Fulfillment>? fulfillments;
+  String? extraData;
+  bool? hasComment;
+  double? fee;
+  UserPosition? shipperPosition;
+  DistanceInfo? deliveryDistance;
 
   Order.fromJson(Map<String, dynamic> json)
       : id = json['id'],
@@ -100,7 +100,7 @@ class Order {
 
   double getSubtotal() {
     double subtotal = 0.0;
-    for (CartLineItem lineItem in cartInfo.productList) {
+    for (CartLineItem lineItem in cartInfo?.productList ?? <CartLineItem>[]) {
       subtotal += lineItem.getTotalPrice();
     }
     return subtotal;

lib/models/payment_platform.dart

@@ -6,19 +6,19 @@ import 'package:flutter/cupertino.dart';
 import '../generated/l10n.dart';
 
 class PaymentPlatform {
-  int id;
-  String name;
-  String code;
-  String method;
-  String icon;
-  String xLogin;
-  String transactionKey;
-  String responseKey;
-  String squareAppId;
-  String squareAccessToken;
-  String squareLocationId;
-  String publishableKey;
-  String merchantId;
+  int? id;
+  String? name;
+  String? code;
+  String? method;
+  String? icon;
+  String? xLogin;
+  String? transactionKey;
+  String? responseKey;
+  String? squareAppId;
+  String? squareAccessToken;
+  String? squareLocationId;
+  String? publishableKey;
+  String? merchantId;
 
   PaymentPlatform(this.code);
 

lib/models/position.dart

@@ -1,7 +1,7 @@
 
 class Position {
-  final double latitude;
-  final double longitude;
+  final double? latitude;
+  final double? longitude;
 
   Position({this.latitude, this.longitude});
 

lib/models/product.dart

@@ -5,23 +5,23 @@ import 'Subproduct.dart';
 import 'product_attribute.dart';
 
 class Product {
-  int id;
-  int businessId;
-  int categoryId;
-  String name;
-  double price;
-  double regularPrice;
-  String description;
-  String detailDescription;
-  String imagePath;
-  String secondImagePath;
-  double monthSales;
-  int rate;
-  double leftNum;
-  List<ProductAttribute> productAttributes;
-  bool nonInventory;
-  String extraData;
-  List<Subproduct> subproducts;
+  int? id;
+  int? businessId;
+  int? categoryId;
+  String? name;
+  double? price;
+  double? regularPrice;
+  String? description;
+  String? detailDescription;
+  String? imagePath;
+  String? secondImagePath;
+  double? monthSales;
+  int? rate;
+  double? leftNum;
+  List<ProductAttribute>? productAttributes;
+  bool? nonInventory;
+  String? extraData;
+  List<Subproduct>? subproducts;
 
   Product(int id, int businessId, String name, double price, String description,
       String imagePath, List<ProductAttribute> productAttributes) {

lib/models/product_attribute.dart

@@ -4,14 +4,14 @@ import 'dart:convert';
 import 'product_option.dart';
 
 class ProductAttribute {
-  int id;
-  String name;
-  List<ProductOption> productOptions;
-  bool singleSelection;
-  bool byQuantity;
-  bool required;
-  String extra;
-  bool disabled;
+  int? id;
+  String? name;
+  List<ProductOption>? productOptions;
+  bool? singleSelection;
+  bool? byQuantity;
+  bool? required;
+  String? extra;
+  bool? disabled;
 
   ProductAttribute.fromJson(Map<String, dynamic> json)
     : id = json['id'],

lib/models/product_detail.dart

@@ -8,30 +8,30 @@ import 'product_attribute.dart';
 import 'product_image.dart';
 
 class ProductDetail {
-  int id;
-  String image;
-  List<ProductImage> images;
-  String sku;
-  String name;
-  double price;
-  double regularPrice;
-  String description;
-  String description2;
-  String detailDescription;
-  double monthSales;
-  int rate;
-  double leftNum;
-  List<ProductAttribute> productAttributes;
-  bool nonInventory;
-  String extraData;
-  String purchaseNote;
-  double weight;
-  double dimentionsLength;
-  double dimentionsWidth;
-  double dimentionsHeight;
-  bool reviewsAllowed;
-  List<Category> categories;
-  List<Subproduct> subproducts;
+  int? id;
+  String? image;
+  List<ProductImage>? images;
+  String? sku;
+  String? name;
+  double? price;
+  double? regularPrice;
+  String? description;
+  String? description2;
+  String? detailDescription;
+  double? monthSales;
+  int? rate;
+  double? leftNum;
+  List<ProductAttribute>? productAttributes;
+  bool? nonInventory;
+  String? extraData;
+  String? purchaseNote;
+  double? weight;
+  double? dimentionsLength;
+  double? dimentionsWidth;
+  double? dimentionsHeight;
+  bool? reviewsAllowed;
+  List<Category>? categories;
+  List<Subproduct>? subproducts;
 
   ProductDetail.fromJson(Map<String, dynamic> json)
     : id = json['id'],

lib/models/product_image.dart

@@ -1,8 +1,8 @@
 import 'dart:convert';
 
 class ProductImage {
-  int id;
-  String image;
+  int? id;
+  String? image;
 
   ProductImage.fromJson(Map<String, dynamic> json)
     : id = json['id'],

lib/models/product_option.dart

@@ -2,11 +2,11 @@
 import 'dart:convert';
 
 class ProductOption {
-  int id;
-  String name;
-  double adjustAmount;
-  String extra;
-  bool disabled;
+  int? id;
+  String? name;
+  double? adjustAmount;
+  String? extra;
+  bool? disabled;
 
   ProductOption.fromJson(Map<String, dynamic> json)
     : id = json['id'],

lib/models/shipping_rate.dart

@@ -4,9 +4,9 @@ import 'dart:convert';
 import 'package:flutter/foundation.dart';
 
 class ShippingRate {
-  String name;
-  double price;
-  List<Rate> rates;
+  String? name;
+  double? price;
+  List<Rate>? rates;
 
   ShippingRate.fromJson(Map<String, dynamic> json)
     : name = json['name'],
@@ -25,7 +25,7 @@ class ShippingRate {
           other is ShippingRate &&
           runtimeType == other.runtimeType &&
           name == other.name &&
-          price.toStringAsFixed(2) == other.price.toStringAsFixed(2) &&
+          price?.toStringAsFixed(2) == other.price?.toStringAsFixed(2) &&
           listEquals(rates, other.rates);
 
   @override
@@ -41,8 +41,8 @@ class ShippingRate {
 }
 
 class Rate {
-  String name;
-  double rate;
+  String? name;
+  double? rate;
 
   Rate.fromJson(Map<String, dynamic> json)
     : name = json['name'],
@@ -59,7 +59,7 @@ class Rate {
           other is Rate &&
           runtimeType == other.runtimeType &&
           name == other.name &&
-          rate.toStringAsFixed(2) == other.rate.toStringAsFixed(2);
+          rate?.toStringAsFixed(2) == other.rate?.toStringAsFixed(2);
 
   @override
   String toString() {

lib/models/simple_business.dart

@@ -4,9 +4,9 @@ import 'dart:convert';
 import 'address.dart';
 
 class Store {
-  int id;
-  String name;
-  Address address;
+  int? id;
+  String? name;
+  Address? address;
 
   Store.fromJson(Map<String, dynamic> json)
     : id = json['id'],

lib/models/simple_product.dart

@@ -1,12 +1,12 @@
 import 'dart:convert';
 
 class SimpleProduct {
-  int id;
-  String name;
-  double price;
-  double regularPrice;
-  String description;
-  String imagePath;
+  int? id;
+  String? name;
+  double? price;
+  double? regularPrice;
+  String? description;
+  String? imagePath;
 
   SimpleProduct.fromJson(Map<String, dynamic> json)
     : id = json['id'],

lib/models/text_value.dart

@@ -2,8 +2,8 @@
 import 'dart:convert';
 
 class TextValue {
-  String text;
-  int value;
+  String? text;
+  int? value;
 
   TextValue.fromJson(Map<String, dynamic> json)
       : text = json['text'],

lib/models/ticket.dart

@@ -4,10 +4,10 @@ import 'dart:convert';
 import 'simple_business.dart';
 
 class TicketFile {
-  int id;
-  String url;
-  String fileName;
-  String fileType;
+  int? id;
+  String? url;
+  String? fileName;
+  String? fileType;
 
   TicketFile.fromJson(Map<String, dynamic> json)
     : id = json['id'],
@@ -29,9 +29,9 @@ class TicketFile {
 }
 
 class Issue {
-  int id;
-  String msg;
-  List<TicketFile> files;
+  int? id;
+  String? msg;
+  List<TicketFile>? files;
 
   Issue.fromJson(Map<String, dynamic> json)
     : id = json['id'],
@@ -51,11 +51,11 @@ class Issue {
 }
 
 class FollowUp {
-  int id;
-  String msg;
-  String poster;
-  String createdAt;
-  List<TicketFile> files;
+  int? id;
+  String? msg;
+  String? poster;
+  String? createdAt;
+  List<TicketFile>? files;
 
   FollowUp.fromJson(Map<String, dynamic> json)
     : id = json['id'],
@@ -79,12 +79,12 @@ class FollowUp {
 }
 
 class Ticket {
-  int id;
-  Issue issue;
-  Store store;
-  List<FollowUp> followUps;
-  bool isClosed;
-  String createdAt;
+  int? id;
+  Issue? issue;
+  Store? store;
+  List<FollowUp>? followUps;
+  bool? isClosed;
+  String? createdAt;
 
   Ticket.fromJson(Map<String, dynamic> json)
     : id = json['id'],

lib/models/user.dart

@@ -2,22 +2,22 @@
 import 'dart:convert';
 
 class User {
-  int id;
-  String username;
-  String nickname;
-  String mobile;
-  String email;
-  String avatarUrl;
-  int lastAddressId;
-  String passCode;
-  double credit;
-  double wallet;
-  int coupon;
-  int points;
-  int orderNum;
-  double pointsToCreditsConversionRate;
-  String contactNumber;
-  String flutterMiniStoreToken;
+  int? id;
+  String? username;
+  String? nickname;
+  String? mobile;
+  String? email;
+  String? avatarUrl;
+  int? lastAddressId;
+  String? passCode;
+  double? credit;
+  double? wallet;
+  int? coupon;
+  int? points;
+  int? orderNum;
+  double? pointsToCreditsConversionRate;
+  String? contactNumber;
+  String? flutterMiniStoreToken;
 
   User.fromJson(Map<String, dynamic> json)
       : id = json['id'],

lib/models/user_position.dart

@@ -2,8 +2,8 @@
 import 'dart:convert';
 
 class UserPosition {
-  double lat;
-  double lng;
+  double? lat;
+  double? lng;
 
   UserPosition.fromJson(Map<String, dynamic> json) :
       lat = double.parse(json['lat'].toString()),

lib/models/waiting_line.dart

@@ -4,8 +4,8 @@ import 'dart:convert';
 import 'waiting_line_item.dart';
 
 class WaitingLine {
-  List<WaitingLineItem> waitingLines;
-  String storeSn;
+  List<WaitingLineItem>? waitingLines;
+  String? storeSn;
 
   WaitingLine.fromJson(Map<String, dynamic> json)
     : waitingLines = (json['waiting_lines'] as List).map((i) => WaitingLineItem.fromJson(i)).toList(),

lib/models/waiting_line_item.dart

@@ -1,11 +1,11 @@
 import 'dart:convert';
 
 class WaitingLineItem {
-  String deviceId;
-  String phone;
-  String createdAt;
-  int peopleCount;
-  int waitingNumber;
+  String? deviceId;
+  String? phone;
+  String? createdAt;
+  int? peopleCount;
+  int? waitingNumber;
 
   WaitingLineItem.fromJson(Map<String, dynamic> json)
     : deviceId = json['device_id'],

lib/utils/http_util.dart

@@ -14,10 +14,8 @@ import '../constants.dart';
 
 typedef void PostCallback(Response response);
 
-String generateSignature(String string, {String key}) {
-  if (key == null) {
-    key = Constants.API_SECRET;
-  }
+String generateSignature(String string, {String? key}) {
+  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"));
@@ -38,16 +36,16 @@ class HttpUtil {
     '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-Country-Code': store.state.locale.countryCode ?? '',
   };
 
   static Future<dynamic> httpGet(String url,
       {
-        Map<String, dynamic> queryParameters,
+        Map<String, dynamic>? queryParameters,
         int businessId = 0,
-        Function(int, int) receiveProgress,
+        Function(int, int)? receiveProgress,
         bool returnError = false,
-        Map<String, String> additionalHeaders,
+        Map<String, String>? additionalHeaders,
       }) async {
     Map<String, dynamic> localHeaders = json.decode(json.encode(headers));
     if (additionalHeaders != null) {
@@ -69,7 +67,7 @@ class HttpUtil {
       requestUrl = url;
     }
 
-    Utils.jsonPrettyPrint(queryParameters);
+    Utils.jsonPrettyPrint(queryParameters ?? {});
 
     Dio dio = Dio();
     try {
@@ -84,9 +82,8 @@ class HttpUtil {
       // print('response data: ${response.data}');
 //      Utils.jsonPrettyPrint(response.data);
 
-      int statusCode = response.statusCode;
       return response.data;
-    } on DioError catch(e) {
+    } on DioException catch(e) {
       print('HttpGet failed, request: $requestUrl, headers: $localHeaders, error ${e.response}');
       if (returnError) {
         return e;
@@ -97,14 +94,14 @@ class HttpUtil {
 
   static Future<dynamic> httpPost(String url, PostCallback callback,
       {
-        Map<String, dynamic> queryParameters,
+        Map<String, dynamic>? queryParameters,
         int businessId = 0,
         bool isFormData = false,
-        Map<String, String> additionalHeaders,
-        Map<String, dynamic> body,
-        FormData formData,
-        Function(int, int) sendProgress,
-        Function(int, int) receiveProgress,
+        Map<String, String>? additionalHeaders,
+        Map<String, dynamic>? body,
+        FormData? formData,
+        Function(int, int)? sendProgress,
+        Function(int, int)? receiveProgress,
         bool returnError = false,
       }) async {
 
@@ -130,15 +127,15 @@ class HttpUtil {
     }
 
     // Don't print body will cause upload Multipart file failed
-    //Utils.jsonPrettyPrint(body);
+    //Utils.jsonPrettyPrint(body ?? {});
 
     Dio dio = Dio();
     dio.interceptors.add(LogInterceptor());
     try {
       Response response = await dio.post(
         requestUrl,
-        queryParameters: queryParameters == null ? {} : queryParameters,
-        data: isFormData ? ((formData != null)?formData:FormData.fromMap(body)) : json.encode(body),
+        queryParameters: queryParameters ?? {},
+        data: isFormData ? ((formData != null)?formData:FormData.fromMap(body ?? {})) : json.encode(body),
         options: Options(
           headers: localHeaders,
           contentType: isFormData ? Headers.formUrlEncodedContentType : Headers.jsonContentType,
@@ -149,17 +146,16 @@ class HttpUtil {
 
 //      Utils.jsonPrettyPrint(response.data);
 
-      int statusCode = response.statusCode;
       if (callback != null) {
         callback(response);
       }
       return response.data;
-    } on DioError catch(e, stacktrace) {
+    } on DioException catch(e, stacktrace) {
       if (e.response != null) {
         try {
-          Utils.jsonPrettyPrint(e.response.data);
+          Utils.jsonPrettyPrint(e.response!.data);
         } catch (err) {
-          print(e.response.data);
+          print(e.response!.data);
         }
       }
       if (returnError) {
@@ -171,12 +167,12 @@ class HttpUtil {
 
   static Future<dynamic> httpPut(String url, PostCallback callback,
       {
-        Map<String, dynamic> queryParameters,
+        Map<String, dynamic>? queryParameters,
         int businessId = 0,
-        Map<String, String> additionalHeaders,
-        Map<String, dynamic> body,
-        Function(int, int) sendProgress,
-        Function(int, int) receiveProgress,
+        Map<String, String>? additionalHeaders,
+        Map<String, dynamic>? body,
+        Function(int, int)? sendProgress,
+        Function(int, int)? receiveProgress,
         bool returnError = false,
       }) async {
 
@@ -207,7 +203,7 @@ class HttpUtil {
     try {
       Response response = await dio.put(
         requestUrl,
-        queryParameters: queryParameters == null ? {} : queryParameters,
+        queryParameters: queryParameters ?? {},
         data: json.encode(body),
         options: Options(
           headers: localHeaders,
@@ -218,14 +214,13 @@ class HttpUtil {
 
 //      Utils.jsonPrettyPrint(response.data);
 
-      int statusCode = response.statusCode;
       if (callback != null) {
         callback(response);
       }
       return response.data;
-    } on DioError catch(e) {
+    } on DioException catch(e) {
       if (e.response != null) {
-        Utils.jsonPrettyPrint(e.response.data);
+        Utils.jsonPrettyPrint(e.response!.data);
       }
       if (returnError) {
         return e;
@@ -236,12 +231,12 @@ class HttpUtil {
 
   static Future<dynamic> httpPatch(String url, PostCallback callback,
       {
-        Map<String, dynamic> queryParameters,
+        Map<String, dynamic>? queryParameters,
         int businessId = 0,
-        Map<String, String> additionalHeaders,
-        Map<String, dynamic> body,
-        Function(int, int) sendProgress,
-        Function(int, int) receiveProgress,
+        Map<String, String>? additionalHeaders,
+        Map<String, dynamic>? body,
+        Function(int, int)? sendProgress,
+        Function(int, int)? receiveProgress,
         bool returnError = false,
       }) async {
 
@@ -268,13 +263,13 @@ class HttpUtil {
       requestUrl = url;
     }
 
-    Utils.jsonPrettyPrint(body);
+    Utils.jsonPrettyPrint(body ?? {});
 
     Dio dio = Dio();
     try {
       Response response = await dio.patch(
         requestUrl,
-        queryParameters: queryParameters == null ? {} : queryParameters,
+        queryParameters: queryParameters ?? {},
         data: json.encode(body),
         options: Options(
           headers: localHeaders,
@@ -285,14 +280,13 @@ class HttpUtil {
 
 //      Utils.jsonPrettyPrint(response.data);
 
-      int statusCode = response.statusCode;
       if (callback != null) {
         callback(response);
       }
       return response.data;
-    } on DioError catch(e) {
+    } on DioException catch(e) {
       if (e.response != null) {
-        Utils.jsonPrettyPrint(e.response.data);
+        Utils.jsonPrettyPrint(e.response!.data);
       }
       if (returnError) {
         return e;
@@ -303,10 +297,10 @@ class HttpUtil {
 
   static Future<dynamic> httpDelete(String url, PostCallback callback,
       {
-        Map<String, dynamic> queryParameters,
+        Map<String, dynamic>? queryParameters,
         int businessId = 0,
-        Map<String, String> additionalHeaders,
-        Map<String, dynamic> body,
+        Map<String, String>? additionalHeaders,
+        Map<String, dynamic>? body,
         bool returnError = false,
       }) async {
 
@@ -333,13 +327,13 @@ class HttpUtil {
       requestUrl = url;
     }
 
-    Utils.jsonPrettyPrint(body);
+    Utils.jsonPrettyPrint(body ?? {});
 
     Dio dio = Dio();
     try {
       Response response = await dio.delete(
         requestUrl,
-        queryParameters: queryParameters == null ? {} : queryParameters,
+        queryParameters: queryParameters ?? {},
         data: json.encode(body),
         options: Options(
           headers: localHeaders,
@@ -348,14 +342,13 @@ class HttpUtil {
 
 //      Utils.jsonPrettyPrint(response.data);
 
-      int statusCode = response.statusCode;
       if (callback != null) {
         callback(response);
       }
       return response.data;
-    } on DioError catch(e) {
+    } on DioException catch(e) {
       if (e.response != null) {
-        Utils.jsonPrettyPrint(e.response.data);
+        Utils.jsonPrettyPrint(e.response!.data);
       }
       if(returnError) {
         return e;