flutter - 如何使用StreamProvider从StateNotifierProvider？

Question

我尝试使用StreamProvider从StateNotifierProvider。
这里是我的StreamProvider，工作正常为止。

final productListStreamProvider = StreamProvider.autoDispose<List<ProductModel>>((ref) {
  CollectionReference ref = FirebaseFirestore.instance.collection('products');
  return ref.snapshots().map((snapshot) {
    final list = snapshot.docs
        .map((document) => ProductModel.fromSnapshot(document))
        .toList();
    return list;
  });
});

现在，我想填充我的购物车将所有的产品在它从无到有。

final cartRiverpodProvider = StateNotifierProvider((ref) => 
new CartRiverpod(ref.watch(productListStreamProvider));

这是我的CartRiverPod StateNotifier

class CartRiverpod extends StateNotifier<List<CartItemModel>> {

  CartRiverpod([List<CartItemModel> products]) : super(products ?? []);

  void add(ProductModel product) {
    state = [...state, new CartItemModel(product:product)];
    print ("added");
  }

  void remove(String id) {
    state = state.where((product) => product.id != id).toList();
  }
}

Answer 1

完成此操作的最简单方法是接受 Reader作为 StateNotifier 的参数。
例如:

class CartRiverpod extends StateNotifier<List<CartItemModel>> {
  CartRiverpod(this._read, [List<CartItemModel> products]) : super(products ?? []) {
    // use _read anywhere in your StateNotifier to access any providers.
    // e.g. _read(productListStreamProvider);
  }

  final Reader _read;

  void add(ProductModel product) {
    state = [...state, new CartItemModel(product: product)];
    print("added");
  }

  void remove(String id) {
    state = state.where((product) => product.id != id).toList();
  }
}

final cartRiverpodProvider = StateNotifierProvider<CartRiverpod>((ref) => CartRiverpod(ref.read, []));