CODEWITHSUNDEEP
firebaseflutter
Taio
Taio

Reputation: 3724

How to resolve this NoSuchMethodError in flutter firebase

I have this code which is supposed to return the userId. Problem is it returns null since the user is signed out. 

@override
void initState() {
// TODO: implement initState
super.initState();
try {
  widget.auth.currentUser().then((userId) {
    setState(() {
     authStatus = userId == null ? AuthStatus.notSignedIn : AuthStatus.signedIn;
    });
  });
} catch (e) {}
}

This still throws an error even after wrapping a catch block around it. the error freezes my app Error:

Exception has occurred.
NoSuchMethodError: The getter 'uid' was called on null.
Receiver: null
Tried calling: uid

The method trying to be called is 

Future<String> currentUser() async {
FirebaseUser user = await _firebaseAuth.currentUser();
return user.uid;
}

Upvotes: 4

Views: 8746

Answers (3)

Ersan Kolay
Ersan Kolay

Reputation: 265

FirebaseUser _user;

  @override
  void initState() {
    super.initState();
    _checkUser();
  }

  @override
  Widget build(BuildContext context) {
    if (_user == null) {
      return AuthStatus.notSignedIn;
    } else {
      return AuthStatus.signedIn;
    }
  }

  Future<void> _checkUser() async {
    _user = await FirebaseAuth.instance.currentUser();
    setState(() {});
  }

Upvotes: 0

Alexandre Leite
Alexandre Leite

Reputation: 1763

Seems like you're watching the login playlist of Andrea Bizzotto, am I right?

I've passed through it too. The way I managed so that I could fix the error was change the position of auth.currentUser() declaration. You probably have created your Auth auth inside the StatelessWidget.

Try to move the instance of Auth from StatelessWidget to your State, right before your void initState().

And also replace your code so that you can access your Auth from the State. Like this:

  @override
  void initState() {
    // TODO: implement initState
    super.initState();
    try {
      auth.currentUser().then((userId) { //I've removed the 'widget.'
        setState(() {
          authStatus =
              userId == null ? AuthStatus.notSignedIn : AuthStatus.signedIn;
        });
      });
    } catch (e) {}
  }

Once you did this, your code should not throw this error anymore.

Upvotes: 3

diegoveloper
diegoveloper

Reputation: 103421

Try this:

     widget.auth.currentUser().then((userId) {
        setState(() {
         authStatus = userId == null ? AuthStatus.notSignedIn : AuthStatus.signedIn;
        });
      }).catchError((onError){
        authStatus = AuthStatus.notSignedIn;
      });

Update If the firebaseAuth return null you can't use uid property from user because it's null.

    Future<String> currentUser() async {
      FirebaseUser user = await _firebaseAuth.currentUser();
      return user != null ? user.uid : null;
    }

Upvotes: 5

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