A value of type 'AuthResult' can't be

问题:

I'm implementing the google sign in method in my project using Firebase Google sign in option, when the add the below line in my code its throwing me the error like:

A value of type 'AuthResult' can't be assigned to a variable of type 'FirebaseUser'

Here's my Code:

final FirebaseAuth _firebaseAuth = FirebaseAuth.instance;
final GoogleSignIn _googlSignIn = new GoogleSignIn();

Future<FirebaseUser> _signIn(BuildContext context) async {

  Scaffold.of(context).showSnackBar(new SnackBar(
    content: new Text('Sign in'),
  ));

  final GoogleSignInAccount googleUser = await _googlSignIn.signIn();
  final GoogleSignInAuthentication googleAuth =await googleUser.authentication;

  final AuthCredential credential = GoogleAuthProvider.getCredential(
    accessToken: googleAuth.accessToken,
    idToken: googleAuth.idToken,
  );

  FirebaseUser userDetails = await _firebaseAuth.signInWithCredential(credential).user;
  ProviderDetails providerInfo = new ProviderDetails(userDetails.providerId);

  List<ProviderDetails> providerData = new List<ProviderDetails>();
  providerData.add(providerInfo);

  UserDetails details = new UserDetails(
    userDetails.providerId,
    userDetails.displayName,
    userDetails.photoUrl,
    userDetails.email,
    providerData,
  );

  Navigator.push(
    context,
    new MaterialPageRoute(
      builder: (context) => new Profile(detailsUser: details),
    ),
  );
  return userDetails;
}

Can someone tell me whats the problem please.

回答1:

The method firebaseAuth.signInWithCredential(credential) returns a value of type AuthResult, therefore you need to do the following :

AuthResult userDetails = await _firebaseAuth.signInWithCredential(credential);

The other alternative and the better one for your code, is since signInWithCredential returns AuthResult and since class AuthResult contains instance variable user of type FirebaseUser, then you can do the following:

FirebaseUser userDetails = (await _firebaseAuth.signInWithCredential(credential)).user;

https://github.com/FirebaseExtended/flutterfire/blob/master/packages/firebase_auth/firebase_auth/lib/src/auth_result.dart#L18