FLUTTER：在HTTP中获取“isFavorite”时出现问题

g52tjvyc  于 2023-04-22  发布在  Flutter
关注(0)|答案(1)|浏览(87)

我正在学习flutter，并为后端学习目的开发一个虚拟商店应用程序。在我的Firebase实时数据库中，'isFavorite'被设置为'true'。但是在刷新屏幕后，'Icons.favorite'被设置为'Icons.favorite_border'。它应该是阴影的。因此，“图标.收藏夹”是正确的图标，因为它在Firebase中是“true”。它消耗了我很多时间，但我想修复它。
dependencies（pubspec.yaml）：

dependencies:
  flutter:
    sdk: flutter
  provider: ^6.0.5
  intl: ^0.18.0
  http: ^0.13.5

main.dart:

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

import './screens/cart_screen.dart';
import './providers/cart.dart';
import './providers/product.dart';
import './screens/products_overview_screen.dart';
import './screens/product_detail_screen.dart';
import './providers/products_provider.dart';
import '../providers/orders.dart';
import './screens/orders_screen.dart';
import './screens/user_product_screen.dart';
import './screens/edit_product_screen.dart';
import './screens/auth_screen.dart';
import './providers/auth.dart';

final MaterialColor primaryColor = MaterialColor(
  0xFFEBEDF3,
  <int, Color>{
    50: Color(0xFFF3F4F7),
    100: Color(0xFFE6E8EC),
    200: Color(0xFFD0D4DD),
    300: Color(0xFFB8BDC9),
    400: Color(0xFFA0A6B2),
    500: Color(0xFF878E9C),
    600: Color(0xFF767D8C),
    700: Color(0xFF636D7A),
    800: Color(0xFF505C68),
    900: Color(0xFF3D4A56),
  },
);

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MultiProvider(
        providers: [
          ChangeNotifierProvider(
            create: (ctx) => Auth(),
          ),
          ChangeNotifierProxyProvider<Auth, ProductsProvider>(
            //update: (ctx, auth, previousProducts) => ProductsProvider(auth.token),
            create: (ctx) => ProductsProvider(
              '',
              '',
              [],
            ),
            update: (ctx, auth, previousProducts) => ProductsProvider(
                auth.token!,
                auth.userId,
                previousProducts == null ? [] : previousProducts.items),
          ),
          ChangeNotifierProvider(
            create: (ctx) => Cart(),
          ),
          ChangeNotifierProxyProvider<Auth, Orders>(
            //update: (ctx, auth, previousProducts) => ProductsProvider(auth.token),
            create: (ctx) => Orders('', []),
            update: (ctx, auth, previousOrders) => Orders(auth.token!,
                previousOrders == null ? [] : previousOrders.orders),
          ),
        ],
        child: Consumer<Auth>(
          builder: (ctx, auth, _) => MaterialApp(
              theme: ThemeData(
                colorScheme: ColorScheme.fromSwatch(primarySwatch: primaryColor)
                    .copyWith(
                  secondary: Colors.blueGrey,
                ),
                fontFamily: 'Lato',
              ),
              home: auth.isAuth ? ProductsOverviewScreen() : AuthScreen(),
              routes: {
                ProductDetailScreen.routeName: (ctx) => ProductDetailScreen(),
                CartScreen.routeName: (ctx) => CartScreen(),
                OrdersScreen.routeName: (ctx) => OrdersScreen(),
                UserProductScreen.routeName: (ctx) => UserProductScreen(),
                EditProductScreen.routeName: (ctx) => EditProductScreen(),
              }),
        ));
  }
}

以下是我的product_overview_screen.dart：

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

import '../widgets/app_drawer.dart';
import '../screens/cart_screen.dart';
import '../widgets/badge.dart';
import '../widgets/products_grid.dart';
import '../providers/cart.dart';
import '../providers/products_provider.dart';

enum FilterOptions {
  Favorites,
  All,
}

class ProductsOverviewScreen extends StatefulWidget {
  @override
  State<ProductsOverviewScreen> createState() => _ProductsOverviewScreenState();
}

class _ProductsOverviewScreenState extends State<ProductsOverviewScreen> {
  var _showOnlyFavorites = false;
  var _isInit = true;
  var _isLoading = false;

  // @override
  void initState() {
    //
    // Future.delayed(Duration.zero).then((_) {
    //   Provider.of<ProductsProvider>(context).fetchAndSetProduct();
    // });
    super.initState();
  }

  @override
  void didChangeDependencies() {
    if (_isInit) {
      setState(() {
        _isLoading = true;
      });

      Provider.of<ProductsProvider>(context).fetchAndSetProduct().then((_) {
        setState(() {
          _isLoading = false;
        });
      });
    }
    _isInit = false;
    // TODO: implement didChangeDependencies
    super.didChangeDependencies();
  }

  @override
  Widget build(BuildContext context) {
    // final productsData = Provider.of<ProductsProvider>(context, listen: false);
    return Scaffold(
      backgroundColor: Colors.grey[100],
      appBar: AppBar(
        title: const Text('MyShop'),
        actions: [
          PopupMenuButton(
            onSelected: (FilterOptions selectedValue) {
              setState(() {
                if (selectedValue == FilterOptions.Favorites) {
                  _showOnlyFavorites = true;
                } else {
                  _showOnlyFavorites = false;
                }
              });
            },
            itemBuilder: (_) => const [
              PopupMenuItem(
                child: Text('Only Favorites'),
                value: FilterOptions.Favorites,
              ),
              PopupMenuItem(
                child: Text('Show All'),
                value: FilterOptions.All,
              ),
            ],
            icon: const Icon(
              Icons.more_vert,
            ),
          ),
          Consumer<Cart>(
            builder: (_, cart, ch) => Badge(
              child: ch as Widget,
              value: cart.itemCount.toString(),
              color: Colors.blueGrey,
              key: UniqueKey(),
            ),
            child: IconButton(
              icon: Icon(
                Icons.shopping_cart,
              ),
              onPressed: () {
                Navigator.of(context).pushNamed(CartScreen.routeName);
              },
            ),
          ),
        ],
      ),
      drawer: AppDrawer(),
      body: _isLoading
          ? Center(
              child: CircularProgressIndicator(),
            )
          : ProductsGrid(_showOnlyFavorites),
    );
  }
}

我的product_item.dart小部件

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

import '../screens/product_detail_screen.dart';
import '../providers/product.dart';
import '../providers/cart.dart';
import '../providers/auth.dart';

class ProductItem extends StatelessWidget {
  // final String id;
  // final String title;
  // final String imageUrl;

  // ProductItem(this.id, this.title, this.imageUrl);

  @override
  Widget build(BuildContext context) {
    final product = Provider.of<Product>(context, listen: false);
    final cart = Provider.of<Cart>(context, listen: false);
    final authData = Provider.of<Auth>(context, listen: false);
    return ClipRRect(
      borderRadius: BorderRadius.circular(8),
      child: GridTile(
        child: GestureDetector(
          onTap: () {
            Navigator.of(context).pushNamed(
              ProductDetailScreen.routeName,
              arguments: product.id,
            );
          },
          child: Image.network(
            product.imageUrl,
            fit: BoxFit.cover,
          ),
        ),
        footer: GridTileBar(
          backgroundColor: Colors.black87,
          leading: Consumer<Product>(
            builder: (ctx, product, _) => IconButton(
              icon: Icon(
                product.isFavorite ? Icons.favorite : Icons.favorite_border,
                color: Theme.of(context).colorScheme.secondary,
              ),
              onPressed: () {
                product.toggleFavoriteStatus(authData.token!, authData.userId);
              },
            ),
          ),
          title: Text(
            product.title,
            textAlign: TextAlign.center,
          ),
          trailing: IconButton(
            icon: Icon(
              Icons.shopping_cart,
              color: Theme.of(context).colorScheme.secondary,
            ),
            onPressed: () {
              cart.addItem(
                  product.id, product.title, product.quantity, product.price);
              ScaffoldMessenger.of(context).hideCurrentSnackBar();
              ScaffoldMessenger.of(context).showSnackBar(SnackBar(
                content: const Text(
                  'Added Item',
                  textAlign: TextAlign.center,
                ),
                duration: const Duration(seconds: 2),
                action: SnackBarAction(
                  label: 'Undo',
                  onPressed: () {
                    cart.removeSingleItem(product.id);
                  },
                ),
              ));
            },
          ),
        ),
      ),
    );
  }
}

我的产品型号

import 'dart:convert';

import 'package:flutter/foundation.dart';
import 'package:http/http.dart' as http;

class Product with ChangeNotifier {
  final String id;
  final String title;
  final String description;
  final double price;
  final String imageUrl;
  bool isFavorite;

  Product({
    required this.id,
    required this.title,
    required this.description,
    required this.price,
    required this.imageUrl,
    this.isFavorite = false,
  });

  void _setFavValue(bool newValue) {
    isFavorite = newValue;
    notifyListeners();
  }

  int? get quantity => null;

  Future<void> toggleFavoriteStatus(String? token, String userId) async {
    final oldStatus = isFavorite;
    isFavorite = !isFavorite;

    final url = Uri.parse(
        'https://shopapp-bd154-default-rtdb.firebaseio.com/userFavorites/$userId/$id.json?auth=$token');
    try {
      final response = await http.put(url,
          body: json.encode({
            'isFavorite': isFavorite,
          }));
      if (response.statusCode >= 400) {
        _setFavValue(oldStatus);
      }
    } catch (error) {
      _setFavValue(oldStatus);
    }
    notifyListeners();
  }

  bool get isFavoriteState {
    return isFavorite;
  }
}

最后是我的products_provider.dart

import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'package:shop_app/models/http_exeception.dart';

import './product.dart';

class ProductsProvider with ChangeNotifier {
  List<Product> _items = [
    // Product(
    //   id: 'p1',
    //   title: 'Red Shirt',
    //   description: 'A red shirt - it is pretty red!',
    //   price: 29.99,
    //   imageUrl:
    //       'https://cdn.pixabay.com/photo/2016/10/02/22/17/red-t-shirt-1710578_1280.jpg',
    // ),
    // Product(
    //   id: 'p2',
    //   title: 'Trousers',
    //   description: 'A nice pair of trousers.',
    //   price: 59.99,
    //   imageUrl:
    //       'https://upload.wikimedia.org/wikipedia/commons/thumb/e/e8/Trousers%2C_dress_%28AM_1960.022-8%29.jpg/512px-Trousers%2C_dress_%28AM_1960.022-8%29.jpg',
    // ),
    // Product(
    //   id: 'p3',
    //   title: 'Yellow Scarf',
    //   description: 'Warm and cozy - exactly what you need for the winter.',
    //   price: 19.99,
    //   imageUrl:
    //       'https://live.staticflickr.com/4043/4438260868_cc79b3369d_z.jpg',
    // ),
    // Product(
    //   id: 'p4',
    //   title: 'A Pan',
    //   description: 'Prepare any meal you want.',
    //   price: 49.99,
    //   imageUrl:
    //       'https://upload.wikimedia.org/wikipedia/commons/thumb/1/14/Cast-Iron-Pan.jpg/1024px-Cast-Iron-Pan.jpg',
    // ),
  ];

  // var _showFavoritesOnly = false;

  final String authToken;
  final String userId;

  ProductsProvider(this.authToken, this.userId, this._items);

  List<Product> get items {
    // if (_showFavoritesOnly) {
    //   return _items.where((prodItem) => prodItem.isFavorite).toList();
    // }
    return [..._items];
  }

  List<Product> get favoriteItems {
    return _items.where((prodItem) => prodItem.isFavorite).toList();
  }

  Product findById(String id) {
    return _items.firstWhere((prod) => prod.id == id);
  }

  Future<void> fetchAndSetProduct() async {
    var url = Uri.parse(
        'https://shopapp-bd154-default-rtdb.firebaseio.com/products.json?auth=$authToken');
    try {
      final response = await http.get(url);
      final extractedData = json.decode(response.body) as Map<String, dynamic>;

      if (extractedData == null) {
        return;
      }
      url = Uri.parse(
          'https://shopapp-bd154-default-rtdb.firebaseio.com/userFavorites/$userId.json?auth=$authToken');
      final favoriteResponse = await http.get(url);
      final favoriteData = json.decode(favoriteResponse.body);
      final List<Product> loadedProducts = [];
      extractedData.forEach((prodId, prodData) {
        loadedProducts.add(Product(
          id: prodId,
          title: prodData['title'] ?? '',
          description: prodData['description'] ?? '',
          price: prodData['price'] ?? 0.0,
          imageUrl: prodData['imageUrl'] ?? '',
          isFavorite: favoriteData == null
              ? false
              : (favoriteData[prodId] ?? false) is bool
                  ? favoriteData[prodId]
                  : false,
        ));
      });
      _items = loadedProducts;
      notifyListeners();
    } catch (error) {
      rethrow;
    }
  }

  Future<void> addProduct(Product product) async {
    try {
      final url = Uri.parse(
          'https://shopapp-bd154-default-rtdb.firebaseio.com/products.json?auth=$authToken');
      final response = await http.post(
        url,
        body: json.encode({
          'title': product.title,
          'description': product.description,
          'imageUrl': product.imageUrl,
          'price': product.price,
        }),
      );
      final newProduct = Product(
          id: json.decode(response.body)['name'],
          title: product.title,
          description: product.description,
          imageUrl: product.imageUrl,
          price: product.price);
      // _items.add(value);
      _items.add(newProduct);
      notifyListeners();
    } catch (error) {
      print(error);
      throw (error);
    }
  }

  Future<void> updateProduct(String id, Product newProduct) async {
    final prodIndex = _items.indexWhere((prod) => prod.id == id);
    if (prodIndex >= 0) {
      final url = Uri.parse(
          'https://shopapp-bd154-default-rtdb.firebaseio.com/products/$id.json?auth=$authToken');
      await http.patch(
        url,
        body: json.encode({
          'title': newProduct.title,
          'description': newProduct.description,
          'price': newProduct.price,
          'imageUrl': newProduct.imageUrl,
        }),
      );
      _items[prodIndex] = newProduct;
      notifyListeners();
    } else {
      print('...');
    }
  }

  Future<void> deleteProduct(String id) async {
    final url = Uri.parse(
        'https://shopapp-bd154-default-rtdb.firebaseio.com/products/$id.json?auth=$authToken');
    final existingProductIndex = _items.indexWhere((prod) => prod.id == id);
    Product? existingProduct = _items[existingProductIndex];

    _items.removeAt(existingProductIndex);
    notifyListeners();
    final response = await http.delete(url);
    if (response.statusCode >= 400) {
      _items.insert(existingProductIndex, existingProduct);
      notifyListeners();
      throw HttpException('Could not delete product.');
    }
    existingProduct = null;
  }

  // updateToken(String? token, _items) {}

  // void showFavoritesOnly() {
  //   _showFavoritesOnly = true;
  //   notifyListeners();
  // }

  // void showAll() {
  //   _showFavoritesOnly = false;
  //   notifyListeners();
  // }
}

我的firebase数据库结构：

flutter

1条答案

按热度按时间
ttygqcqt

ttygqcqt1#

所以我所做的是，我首先验证了'favoriteData'的值，然后将其传递给'isFavorite'。

Future<void> fetchAndSetProduct() async {
    var url = Uri.parse(
        'https://shopapp-bd154-default-rtdb.firebaseio.com/products.json?auth=$authToken');
    try {
      final response = await http.get(url);
      final extractedData = json.decode(response.body) as Map<String, dynamic>;

      if (extractedData == null) {
        return;
      }
      url = Uri.parse(
          'https://shopapp-bd154-default-rtdb.firebaseio.com/userFavorites/$userId.json?auth=$authToken');
      final favoriteResponse = await http.get(url);
      final favoriteData = json.decode(favoriteResponse.body);
      final List<Product> loadedProducts = [];
      extractedData.forEach((prodId, prodData) {
        var isFavorite = false;
        if (favoriteData != null && favoriteData[prodId] != null) {
          isFavorite = favoriteData[prodId]['isFavorite'] is bool &&
              favoriteData[prodId]['isFavorite'];
        }
        loadedProducts.add(Product(
          id: prodId,
          title: prodData['title'] ?? '',
          description: prodData['description'] ?? '',
          price: prodData['price'] ?? 0.0,
          imageUrl: prodData['imageUrl'] ?? '',
          isFavorite: isFavorite,

        ));
      });
      print(json.decode(favoriteResponse.body));
      _items = loadedProducts;
      notifyListeners();
    } catch (error) {
      rethrow;
    }
  }
赞(0）分享  回复(0）举报  2023-04-22
我来回答

相关问题

    查看更多

    热门标签

    更多
    JavaquerypythonNode开发语言requestUtil数据库Table后端算法LoggerMessageElementParser

    最新问答

    更多
    • 蜀ICP备2022004421号-2 NULL123 https://www.null123.com © All rights reserved
    • 本站内容来源互联网,如果侵犯您的权益请联系我们删除, 联系方式：448109455@qq.com