BLOC losing context when navigating to a new page - flutter

Question

I'm using the BLOC pattern to authenticate a user in my app. I have a main BlocProvider that wraps my app. And a BlocBuilder to build according to the authentication state.
If the user is unauthenticated i have onboarding / intro screens that will navigate to the login screen.
The login screen is wrapped in another BlocProvider that contains a button that will do the login, and add a logged in event when the login is successful.
Problem is when i navigate from the onboarding screens i loose the main authenticationBloc context. What do i need to to to have access to the authentication bloc after i pushed a new screen.
void main() {
WidgetsFlutterBinding.ensureInitialized();
Bloc.observer = SimpleBlocObserver();
runApp(
MyApp(),
);
}
class AuthenticationWrapper extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
home: BlocProvider<AuthenticationBloc>(
create: (context) => AuthenticationBloc()..add(AppStarted()),
child: MyApp(),
),
);
}
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return BlocListener<AuthenticationBloc, AuthenticationState>(
listener: (context, state) {
if (state is Authenticated) {
_appUserProfileRepository = AppUserProfileRepository();
}
},
child: BlocBuilder<AuthenticationBloc, AuthenticationState>(
builder: (context, state) {
_authCredentialHelper = state.authCredentialHelper;
if (state is Uninitialized) {
return SplashScreen();
}
if (state is Unauthenticated) {
return OnboardingScreens(authCredentialHelper: _authCredentialHelper);
}
if (state is InvalidRegistration) {
return RegisterProfileScreen(authCredentialHelper: _authCredentialHelper);
}
if (state is Authenticated) {
xxx
}
return Scaffold(body: Center(child: LoadingIndicator()));
},
),
);
}
}
This is the onboarding screen where i loose the authenticationbloc context as soon as i navigate
class OnboardingScreens extends StatelessWidget {
final AuthCredentialHelper authCredentialHelper;
OnboardingScreens({this.authCredentialHelper});
_pages(BuildContext context) {
return [
xxx
];
}
_getStartedClicked(BuildContext context) {
Navigator.push(context, MaterialPageRoute(builder: (context) {
return LoginScreen(authCredentialHelper: authCredentialHelper);
}));
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: SafeArea(
child: IntroductionScreen(
pages: _pages(context),
onDone: () => _getStartedClicked(context),
showSkipButton: true,
done: xxx
),
),
);
}
}
When adding a breakpoint at 1. the context is fine with a valid value for BlocProvider.of(context)
Stepping to 2. gives me an error:
BlocProvider.of() called with a context that does not contain a Cubit of type AuthenticationBloc.
_getStartedClicked(BuildContext context) {
1----->Navigator.push(context, MaterialPageRoute(builder: (context) {
2----->return LoginScreen(authCredentialHelper: authCredentialHelper);
}));
}
This is the LoginScreen code
class LoginScreen extends StatelessWidget {
final AuthCredentialHelper authCredentialHelper;
LoginScreen({this.authCredentialHelper});
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
leading: IconButton(
icon: Icon(Icons.arrow_back, color: darkBlue),
onPressed: () => Navigator.of(context).pop(),
),
backgroundColor: Colors.transparent,
elevation: 0.0,
),
body: SafeArea(
child: Center(
child: BlocProvider<LoginBloc>(
create: (context) => LoginBloc(authCredentialHelper: authCredentialHelper),
child: LoginForm(authCredentialHelper: authCredentialHelper),
),
),
),
);
}
}
Getting this error:
The following assertion was thrown building _InheritedProviderScope<LoginBloc>(value: Instance of 'LoginBloc'):
BlocProvider.of() called with a context that does not contain a Cubit of type AuthenticationBloc.
No ancestor could be found starting from the context that was passed to BlocProvider.of<AuthenticationBloc>().
This can happen if the context you used comes from a widget above the BlocProvider.

Answer 1

Change this :
Navigator.push(context, MaterialPageRoute(builder: (context) {
return LoginScreen(authCredentialHelper: authCredentialHelper);
}));
to
Navigator.push(
context,
MaterialPageRoute(builder: (contextLoginScreen) {
return BlocProvider.value(
value: context.bloc<AuthenticationBloc>(),
child: LoginScreen(authCredentialHelper: authCredentialHelper));
}),
);