Flutter's GetIt with the app in background

Question

I'm having issues with using GetIt while the app is in background. With the app is in focus everything works great but the moment I switch focus everything breaks. What's my error here?

I'm using GetIt 6.1.1, flutter 2.0.5, here's the stacktrace

I/flutter ( 5125): FlutterFire Messaging: An error occurred in your background messaging handler:
I/flutter ( 5125): 'package:get_it/get_it_impl.dart': Failed assertion: line 315 pos 7: 'instanceFactory != null': Object/factory with  type NotificationCubit is not registered inside GetIt. 
I/flutter ( 5125): (Did you accidentally do GetIt sl=GetIt.instance(); instead of GetIt sl=GetIt.instance;
I/flutter ( 5125): Did you forget to register it?)

Here's my GetIt setup

get_it.dart

GetIt getIt = GetIt.instance;

void setupGetIt() {
  getIt.registerSingleton<NotificationCubit>(NotificationCubit());
}

main.dart

void main() async {
  // some other methods
  setupGetIt();
  runApp(MyApp());
}

And the method that throws the error.

void _handleMessage(RemoteMessage message) {
  getIt
      .get<NotificationCubit>()
      .addNotification(NotificationClassName.fromRemoteMessage(message));

  _displaySnackBar(message);
}

Answer 1

You need to call setupGetIt(); again in your _handleMessage, the code becomes:

void _handleMessage(RemoteMessage message) {
   
   //Add it here
   setupGetIt();
   getIt
    .get<NotificationCubit>()
    .addNotification(NotificationClassName.fromRemoteMessage(message));

  _displaySnackBar(message);
 }

The error is thrown because when _handleMessage method is called, the compiler fails to find getIt.registerSingleton<NotificationCubit>(NotificationCubit()); which registers NotificationCubit>.