StateNotifier as Listenable

[GitGud31]

I'm trying out go_router with riverpod, and I was wondering on how to get a Listenable from a riverpod provider. I'm currently using ChangeNotifier and it works fine, but I want to use StateNotifier instead and I don't know how to make it work. Any suggestions on how I can make refreshListenable (from go_router) listen to a StateNotifier?

Repo link: App sample

file: root_screen.dart

final _router = GoRouter(
...
refreshListenable: ref.watch(authStateNotifier) // I want to use StateNotifier here instead.
...
);

file: auth_state_notifier.dart

final authStateNotifier =
    ChangeNotifierProvider<AuthStateNotifier>((_) => AuthStateNotifier());

class AuthStateNotifier extends ChangeNotifier {
  bool _isAuthenticated = false;

  bool get isAuthenticated => _isAuthenticated;

  void authenticate() {
    _isAuthenticated = true;
    notifyListeners();
  }

  void logout() {
    _isAuthenticated = false;
    notifyListeners();
  }
}

[iamarnas]

You handle the simple boolean state. Your StateNotifier should look like this:

class AuthStateNotifier extends StateNotifier<bool>{
  AuthStateNotifier() : super(false);

  void authenticate() {
    state = true;
  }

  void logout() {
    state = false;
  } 

[iamarnas]

And tip att the end. You don't need make simple things depend on Riverpod.

In your case, ValueNotifier is easier.

[GitGud31]

Yup that's what I noticed (StateNotifier doesn't extend Listenable) checking the doc, so I'll continue to use ChangeNotifier. And I want to ask now, why doesn't StateNotifier extend Listenable like ChangeNotifier does ? as I understand it they're almost similar (in terms of what they're created for/todo), right?

And thanks for the replies!!

[GitGud31]

In your case, ValueNotifier is easier.

Yes, indeed. But that's just sample app, so I tried to mimic an auth situation with only a boolean and see how things work (btw riverpod and go_router), Thanks again :D

[iamarnas]

Why doesn't StateNotifier extend Listenable like ChangeNotifier does ?

Because StateNotifier not depend on Flutter, it pure Dart. You can move you code to another project to example.

[GitGud31]

I see, I appreciate your anwsers, thanks !

[yeasir-bjit]

@freezed
class AuthState with _$AuthState {
  const AuthState._();
  const factory AuthState.initial() = _Initial;
  const factory AuthState.authenticated() = _Authenticated;
  const factory AuthState.unauthenticated() = _Unauthenticated;
  const factory AuthState.failure(AuthFailure failure) = _Failure;
}

My state class looks like this. I am using freezed union for this. How do handle the routing flow based on the authentication state? I my project, oAuth2 is used so that when pressing the login button it opens a webview (modally on iOS). If the user cancels the webview, then authentication fails and the state becomes unauthenticated, and I need to show a failure alert.