Riverpod's AsyncValue's when method's properties loading: and error: does not work as official document

Question

根据 https://pub.dev/documentation/riverpod/latest/riverpod/AsyncValue-class.html ，我创建了以下代码；

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

class User {
  final name = '';
}

final userProvider = StreamProvider<User>((_) async* {
  // fetch the user
});

class Example extends ConsumerWidget {
  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final AsyncValue<User> user = ref.watch(userProvider);

    return user.when(
      loading: () => CircularProgressIndicator(), // <---here
      error: (error, stack) => Text('Oops, something unexpected happened'), // <---here
      data: (User user) => Text('Hello ${user.name}'),
    );
  }
}

我在加载时遇到以下错误：和错误：

正在加载：

The argument type 'CircularProgressindicator Function()' can't be assigned to the parameter type 'Widget Function(Async Value?)'. (Documentation)

错误：

The argument type 'Text Function(Object, StackTrace?)' can't be assigned to the parameter type 'Widget Function (Object, StackTrace?, Async Data?)'. (Documentation)

error screen

这是今天突然发生的事情。直到昨天还完全没有问题。

我正在使用 flutter_riverpod-1.00-dev.11.

我已经做了“flutter clean”，删除了pubspec.lock，“flutter pub get”。

你有解决这个问题的办法吗？

Answer 1

最近更新了文档，因为 AsyncValue 在 master 分支上发生了更改，但更改尚未发布。

由于您使用的是版本 1.0.0-dev.11，因此语法为：

return user.when(
  loading: (_) => CircularProgressIndicator(), // <---here
  error: (error, stack, _) => Text('Oops, something unexpected happened'), // <---here
  data: (User user) => Text('Hello ${user.name}'),
);

最近删除了那些额外的参数，因此您不应该尝试使用它们。

Riverpod's AsyncValue's when method's properties loading: and error: does not work as official document

Riverpod's AsyncValue's when method's properties loading: and error: does not work as official document

flutter

riverpod

asyncvalue