CODEWITHSUNDEEP
firebaseflutterfirebase-authentication
MBK
MBK

Reputation: 3424

Flutter Firebase authStateChanges() with Provider & NullSafety On

I have seen many questions like this, but most of them are outdated and not using null safety.

I am using FirebaseAuth and provider to stream & update the users state (Is he logged in or not)

what's wrong with this code?

AuthenticationProvider Class

class AuthenticationProvider {
  final FirebaseAuth _firebaseAuth;
  AuthenticationProvider(this._firebaseAuth);

   Stream<User?> get authState => _firebaseAuth.authStateChanges();
  
}

main.dart

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MultiProvider(
      providers: [
        Provider<AuthenticationProvider>(
          create: (_) => AuthenticationProvider(FirebaseAuth.instance),
        ),
        StreamProvider(
          create: (context) =>
              context.read<AuthenticationProvider>().authState,
          initialData: null,
        ),
      ],
      child: MaterialApp(
        title: 'Flutter Demo',
        
        home: SplashScreen(),
        
      ),
    );
  }
}

SplashScreen() class

 class SplashScreen extends StatelessWidget {
      @override
      Widget build(BuildContext context) {
        final firebaseUser = context.watch<User>();
    
        if (firebaseUser != null) { // This line warning: The operand can't be null, so the condition is always true. Remove the condition.
          return Dashboard();
        }
        return StartingScreen();
      }
    }

Upvotes: 2

Views: 1714

Answers (1)

Frank van Puffelen
Frank van Puffelen

Reputation: 600141

Given that you start with a stream of User?:

Stream<User?> get authState => _firebaseAuth.authStateChanges();

I think the watch should be on User? too. So:

final firebaseUser = context.watch<User?>();

Upvotes: 4

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