构建 MyApp（脏，状态：_MyAppState#86032）抛出了以下 NoSuchMethodError：

Question

我收到此错误消息，但不知道如何解决：

Exception caught by widgets library The following NoSuchMethodError was thrown building MyApp(dirty, state: _MyAppState#86032):

The method 'call' was called on null.

Receiver: null

Tried calling: call(Instance of 'ChangeNotifierProvider<UserLoggedIn>')```

这是导致此问题的代码：

void main() {
    runApp(ProviderScope(child:MyApp()));
 }

class MyApp extends StatefulHookWidget {

 @override
 _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp>

我想我应该更改我当前使用的 flutter 版本，因为在我更新 flutter 时发生了这种情况，但那没有用。

Answer 1

听起来您可能已将 flutter 更新到具有空安全性的版本。发生这种情况时，methods 不能为 null，即使在以前版本的 flutter 中是可以的运行。看看这些参考资料： Null Safety

Migration

构建 MyApp（脏，状态：_MyAppState#86032）抛出了以下 NoSuchMethodError：

The following NoSuchMethodError was thrown building MyApp(dirty, state: _MyAppState#86032):

dart

flutter

dart-null-safety