Если это поможет. Я создаю класс шаблон class Pattern extends StatelessWidget {
@override Widget build(BuildContext context) {
return Scaffold(
body: BlocProvider<NavigationBloc>(
create: (context) => NavigationBloc(),
child: BlocBuilder<NavigationBloc, NavigationStates>(
builder: (context, navigationState) {
return navigationState as Widget;
},
),
),
);
}
}