查看firebase_auth github存储库
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';}
