(Flutter/Riverpod) StateProvider 文檔示例未更新

Question

Riverod 的 StateProvider 示例尚未更新。

https://pub.dev/documentation/riverpod/latest/riverpod/StateProvider-class.html

final selectedProductIdProvider = StateProvider<String?>((ref) => null);
final productsProvider = StateNotifierProvider<ProductsNotifier, List<Product>>(
    (ref) => ProductsNotifier());

Widget build(BuildContext context, WidgetRef ref) {
  final List<Product> products = ref.watch(productsProvider);
  final selectedProductId = ref.watch(selectedProductIdProvider);

  return ListView(
    children: [
      for (final product in products)
        GestureDetector(
          onTap: () => selectedProductId.state = product.id,
          child: ProductItem(
            product: product,
            isSelected: selectedProductId.state == product.id,
          ),
        ),
    ],
  );
}

現在 Riverpod 已經成為 v1 穩定版，上面的代碼不再工作了。

以下是 Riverpod v1 stable 的正確代碼嗎？

final selectedProductIdProvider = StateProvider<String?>((ref) => null);
final productsProvider = StateNotifierProvider<ProductsNotifier, List<Product>>(
    (ref) => ProductsNotifier());

class Foo2 extends ConsumerWidget {
  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final List<Product> products = ref.watch(productsProvider);
    final String? selectedProductId = ref.watch(selectedProductIdProvider);
    final StateController<String?> selectedProductIdController =
        ref.watch(selectedProductIdProvider.notifier);

    return ListView(
      children: [
        for (final product in products)
          GestureDetector(
            onTap: () => selectedProductIdController.state = product.id,
            child: ProductItem(
              product: product,
              isSelected: selectedProductId == product.id,
            ),
          ),
      ],
    );
  }
}

Answer 1

哎呀！

您的代碼是正確的，盡管您不必在build中獲取通知程序，也可以在onTap中進行：

onTap: () => ref.read(selectedProductIdProvider.notifier).state = product.id,