Flutter电商应用 #

lib/
├── main.dart
├── app.dart
├── models/
│   ├── product.dart
│   ├── cart_item.dart
│   └── user.dart
├── providers/
│   ├── products_provider.dart
│   ├── cart_provider.dart
│   └── auth_provider.dart
├── services/
│   ├── api_service.dart
│   └── storage_service.dart
├── screens/
│   ├── home/
│   ├── product/
│   ├── cart/
│   └── profile/
├── widgets/
│   ├── product_card.dart
│   └── cart_item_widget.dart
└── utils/
    ├── constants.dart
    └── validators.dart

class ProductsProvider extends ChangeNotifier {
  List<Product> _products = [];
  bool _isLoading = false;
  
  List<Product> get products => _products;
  bool get isLoading => _isLoading;
  
  Future<void> fetchProducts() async {
    _isLoading = true;
    notifyListeners();
    
    try {
      _products = await ApiService().getProducts();
    } finally {
      _isLoading = false;
      notifyListeners();
    }
  }
}

class CartProvider extends ChangeNotifier {
  final Map<String, CartItem> _items = {};
  
  Map<String, CartItem> get items => _items;
  int get itemCount => _items.length;
  double get totalAmount =>
      _items.values.fold(0, (sum, item) => sum + item.price * item.quantity);
  
  void addItem(Product product) {
    if (_items.containsKey(product.id)) {
      _items[product.id]!.quantity++;
    } else {
      _items[product.id] = CartItem(
        id: product.id,
        title: product.title,
        price: product.price,
        quantity: 1,
      );
    }
    notifyListeners();
  }
  
  void removeItem(String productId) {
    _items.remove(productId);
    notifyListeners();
  }
  
  void clear() {
    _items.clear();
    notifyListeners();
  }
}