小编Abd*_*hTh的帖子

我是 Flutter 的新手。我有Firebase Auth/Google Auth 的问题FirebaseUser未定义代码：

FirebaseAuth _auth = FirebaseAuth.instance;
GoogleSignIn googleSignIn = GoogleSignIn();

Future<FirebaseUser> currentUser() async { // The Issue is here in the Future<>
  final GoogleSignInAccount account = await googleSignIn.signIn();
  final GoogleSignInAuthentication authentication =
      await account.authentication;

  final GoogleAuthCredential credential = GoogleAuthProvider.getCredential(
      idToken: authentication.idToken, accessToken: authentication.accessToken);

  final AuthResult authResult = await _auth.signInWithCredential(credential);
  final FirebaseUser user = authResult.user; // and here as I can't define this FirebaseUser object to return

  return user;
}

pubspec.yml

dependencies:
  flutter:
    sdk: …

I'm trying to add WidgetsBindingObserver accoidring to (https://medium.com/@phongyewtong/best-method-to-restart-reload-your-flutter-app-on-startup-2f787cecc6d6)

class MyApp extends StatefulWidget with WidgetsBindingObserver {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);   // The Error is right here
  }

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);

    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return MaterialHomeApp();
  }

The Erros says The argument type '_MyAppState' can't be assigned to the parameter type 'WidgetsBindingObserver'.dartargument_type_not_assignable