Flutter Firebase.signInWithGoogle method not found

Question

I am trying to add Google Authentication in my Flutter Application. But my Android studio is not able to find the method signInWithGoogle under FirebaseAuth class. I mean to say when I write FirebaseAuth.signInWithGoogle Android studio complains saying The method signInWithGoogle isn't defined for the class Firebase.

I already have the have Firebase.signInWithEmailAndPassword and it is working fine.

I have below dependency in pubspec.yaml firebase_auth: ^0.8.0+1

Below are my imports in the class...

import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/material.dart';
import 'package:google_sign_in/google_sign_in.dart';
import 'package:my_project/auth.dart';
import 'package:my_project/register.dart';
import 'package:my_project/signin/button_list.dart';
import 'package:my_project/signin/button_view.dart';
import 'package:my_project/utils.dart';
class _LoginPageState extends State<LoginPage> {
 final formKey = GlobalKey<FormState>();

// Google Sign In
final GoogleSignIn _googleSignIn = GoogleSignIn();
final FirebaseAuth _auth = FirebaseAuth.instance; // No errors so far

below is the method in the same class that shows the error

Also when I click the ctrl + space to see all the methods under FirebaseAuth it is not showing the signInWithGoogle method at all.

please help! Thanks in Advance...

Answer 1

check out the example provided in the firebase_auth github repo https://github.com/flutter/plugins/blob/master/packages/firebase_auth/example/lib/main.dart#L70

Future<String> _testSignInWithGoogle() async {
    final GoogleSignInAccount googleUser = await _googleSignIn.signIn();
    final GoogleSignInAuthentication googleAuth =
        await googleUser.authentication;
    final AuthCredential credential = GoogleAuthProvider.getCredential(
      accessToken: googleAuth.accessToken,
      idToken: googleAuth.idToken,
    );

    final AuthResult authResult = await _auth.signInWithCredential(credential);
    final FirebaseUser user = authResult.user;
    assert(user.email != null);
    assert(user.displayName != null);
    assert(!user.isAnonymous);
    assert(await user.getIdToken() != null);

    final FirebaseUser currentUser = await _auth.currentUser();
    assert(user.uid == currentUser.uid);

    return 'signInWithGoogle succeeded: $user';
}

Answer 2

Adding to the accepted answer, since firebase_auth version 0.12.0:

Sign-in methods now return AuthResult instead of FirebaseUser. Retrieve the FirebaseUser using the user property of AuthResult.

So the actual correct solution is:

...
    final AuthResult authResult = await _auth.signInWithCredential(credential);
    final FirebaseUser user = authResult.user;
...