my_app_state.dart

class _MyAppState extends State<MyApp> {

  final GlobalKey<NavigatorState> _navigatorKey = GlobalKey();

  @override
  Widget build(BuildContext context) {
    return BlocProvider<NavigatorBloc>(
      bloc: NavigatorBloc(navigatorKey: _navigatorKey),
      child: MaterialApp(
        navigatorKey: _navigatorKey,
        title: 'My App',
        home: HomePage(),
      ),
    );
  }
}