E/flutter (26872): [ERROR:flutter/lib/ui/ui_dart_state.cc(199)] Unhandled Exception: Null check operator used on a null value E/flutter (26872): #0
MethodChannelFirebaseMessaging.registerBackgroundMessageHandler (package:firebase_messaging_platform_interface/src/method_channel/method_channel_messaging.dart:173:53) E/flutter (26872): #1
FirebaseMessagingPlatform.onBackgroundMessage= (package:firebase_messaging_platform_interface/src/platform_interface/platform_interface_messaging.dart:108:16)
// Background Messaging Set Up
Future<void> _firebaseMessagingBackgroundHandler(
RemoteMessage message) async {
print('background message');
}
FirebaseMessaging.onBackgroundMessage(_firebaseMessagingBackgroundHandler);
runApp(....)
I am getting an error for this code on Android system. Everything works except when the app is terminated.
What works on Android:
What does not work on Android:
What works on iOS:
What does not work on iOS:
I have no clue why I am getting that null value error on Android system and how can I fix this issue? Also, is it true that I can not receive the Data only
push notification on iOS when the app is terminated?
I had the same error as like you, on the same line. I checked out docs and it says 2 things about background message handler.
In my case it was not a top-level function, it was declared inside a class. When you move your handler out of any class or function, so that it is a top-level function and doesn't require any class or method initialisation then the error will be gone.