Google authentication problem (Flutter and Firebase) - firebase

Question

I am flutter-newbie and I have one problem: I want to add Google authentication to my flutter app with firebase. This is my code for login screen:
import 'package:PixiCall/resources/firebase_repository.dart';
import 'package:PixiCall/screens/home_screen.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/material.dart';
class LoginScreen extends StatefulWidget {
#override
_LoginScreenState createState() => _LoginScreenState();
}
class _LoginScreenState extends State<LoginScreen> {
FirebaseRepository _repository = FirebaseRepository();
#override
Widget build(BuildContext context) {
return Scaffold(
body: loginButton(),
);
}
Widget loginButton() {
return FlatButton(
padding: EdgeInsets.all(35),
child: Text(
'Login',
style: TextStyle(
fontSize: 25,
fontWeight: FontWeight.w900,
letterSpacing: 1.2,
),
),
onPressed: () => performLogin,
);
}
void performLogin() {
_repository.signIn().then((User user) {
if (user != null) {
authenticateUser(user);
} else {
print('There was an error');
}
});
}
void authenticateUser(User user, BuildContext context) {
_repository.authenticateUser(user).then((isNewUser) {
if (isNewUser) {
_repository.addDataToDb(user).then((value) {
Navigator.pushReplacement(context,
MaterialPageRoute(builder: (context) {
return HomeScreen();
}));
});
} else {
Navigator.pushReplacement(context,
MaterialPageRoute(builder: (context) {
return HomeScreen();
}));
}
});
}
}
I have this error here:
lib/screens/login_screen.dart:39:25: Error: Too few positional arguments: 2 required, 1 given.
authenticateUser(user);
What is the other parameter which I have to add?
Also I think that I have one more mistake in other file. This is the code from other file:
import 'package:PixiCall/models/user.dart';
import 'package:PixiCall/utils/utilities.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:google_sign_in/google_sign_in.dart';
class FirebaseMethods {
final FirebaseAuth _auth = FirebaseAuth.instance;
GoogleSignIn _googleSignIn = GoogleSignIn();
static final FirebaseFirestore firestore = FirebaseFirestore.instance;
//user class
User1 user = User1();
Future<User> getCurrentUser() async {
User currentUser;
currentUser = await _auth.currentUser;
return currentUser;
}
Future<User> signIn() async {
GoogleSignInAccount _signInAccount = await _googleSignIn.signIn();
GoogleSignInAuthentication _signInAuthentication =
await _signInAccount.authentication;
final AuthCredential credential = GoogleAuthProvider.credential(
accessToken: _signInAuthentication.accessToken,
idToken: _signInAuthentication.idToken,
);
User user = await _auth.signInWithCredential(credential);
return user;
}
Future<bool> authenicateUser(User user) async {
QuerySnapshot result = await firestore
.collection('users')
.where('email', isEqualTo: user.email)
.get();
final List<DocumentSnapshot> docs = result.docs;
//if user is registered then length of list > 0 or else less than 0
return docs.length == 0 ? true : false;
}
Future<void> addDataToDb(User currentUser) async {
String username = Utils.getUsername(currentUser.email);
user = User1(
uid: currentUser.uid,
email: currentUser.email,
name: currentUser.displayName,
profilePhoto: currentUser.photoURL,
username: username);
firestore.collection('users').doc(currentUser.uid).set(user.toMap(user));
}
}
This is the mistake in console:
lib/resources/firebase_methods.dart:32:17: Error: A value of type 'UserCredential' can't be assigned to a variable of type 'User'.
Sorry if I confused you, as I said, I am newbie. If you want any other informations please ask here.

Answer 1

For the first mistake , you defined a function void authenticateUser(User user, BuildContext context) so when you use it, it expects 2 arguments a User type object and a BuildContext object
Then you are calling this function in
void performLogin() {
_repository.signIn().then((User user) {
if (user != null) {
authenticateUser(user);
} else {
print('There was an error');
}
});
}
You are passing only the User object, missing the BuildContext

Answer 2

For GoogleSingIn this was my solution:
class AuthService {
final FirebaseAuth _auth = FirebaseAuth.instance;
final GoogleSignIn _googleSignIn = GoogleSignIn();
//create user object based on FB json
User _userFromFirebaseUser(FirebaseUser user) {
return user != null
? User(uid: user.uid, emailVerified: user.isEmailVerified)
: null;
}
//auth change user stream
Stream<User> get user {
return _auth.onAuthStateChanged.map(_userFromFirebaseUser);
}
Future<User> singInUsingGoogle() async {
int age;
String email;
String name;
String lastname;
final GoogleSignInAccount googleUser = await _googleSignIn.signIn();
final GoogleSignInAuthentication googleAuth = await googleUser.authentication;
final AuthCredential credential = GoogleAuthProvider.getCredential(
idToken: googleAuth.idToken, accessToken: googleAuth.accessToken);
final result = await _auth.signInWithCredential(credential);
FirebaseUser user = result.user;
print(result.user.providerData);
await DatabaseService(uid: user.uid).createUserData(
//user info
)