Using Flutter ChangeNotifierProvider for authentication - firebase

Question

I am using ChangeNotifierProvider to handle app state for my flutter app.
My main.dart file
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:flutter_app/services/auth.dart';
Future<void> main() async {
WidgetsFlutterBinding.ensureInitialized();
await Firebase.initializeApp();
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return ChangeNotifierProvider<AuthService>(
create: (context) => AuthService(), // initializes auth.dart file here
child: MaterialApp(
initialRoute: '/',
onGenerateRoute: RouteGenerator.generateRoute,
debugShowCheckedModeBanner: false,
title: '...',
home: WelcomeScreen(),
));
}
}
I am trying to change the value of the uid field here in auth.dart
auth.dart file
import 'package:flutter/material.dart';
import 'package:firebase_auth/firebase_auth.dart';
class AuthService with ChangeNotifier {
final FirebaseAuth _auth = FirebaseAuth.instance;
String uid = ""; //initial value of uid
UserM _userFromFirebaseUser(User user) {
return user != null ? UserM(uid: user.uid) : null;
}
Stream<UserM> get user {
return null;
}
Future signInWithEmail(String email, String password) async {
try {
UserCredential result = await _auth.signInWithEmailAndPassword(
email: email, password: password);
User user = result.user;
uid = user.uid; //trying to change uid here
print('user id: $uid'); //new value is printed here
notifyListeners();
return _userFromFirebaseUser(user);
} catch (e) {
print(e.toString());
return null;
}
}
uid changes but then when i try to get the new value in another file, i still get the old value which is the empty string declared on top.
This is how i am trying to access it
final auth = Provider.of<AuthService>(context, listen: true).uid;
print(auth);
What am I doing wrong please?

Answer 1

I don't get why there is a need to use Provider to get the uid of a user in Firebase. You can get the uid synchronously by doing currentUser.uid.
Here is an example:
print(FirebaseAuth.instance.currentUser.uid);