Failed to initialize Firebase app instance from an isolate


I am trying to interact with the Firestore from a separate isolate. So far I am stacked on Firebase app initialization inside the isolate.


Future<void> main() async {
  await Firebase.initializeApp();
  print("Firebase app initialized in the main isolate");


void trackActivityInBackground(message) async {
  await Firebase.initializeApp();
  print("Firebase app initialized in an isolate");

top-level function

While trying to initialize the FirebaseApp instance inside the isolate I get an exception
Unhandled Exception: Exception: Null check operator used on a null value

If I add WidgetsFlutterBinding.ensureInitialized() on the first line of trackActivityInBackground, I get an exception:
UI actions are only available on root isolate.

Under the hood, when await Firebase.initializeApp() is called, after a series of calls finally the app tries to get binaryMessenger, but when I dived deeper, I’ve noticed that both _binaryMessenger and ServiceBinding.instance are null here

BinaryMessenger get binaryMessenger => _binaryMessenger ?? ServicesBinding.instance!.defaultBinaryMessenger;

So the source of the crash is clear, what is not clear, is how to make it work? 😀

Thanks for the help in advance!


In refernce to this question the following github thread answers this question.

Answered By – Rajeev Tirumalasetty

Answer Checked By – Marilyn (FlutterFixes Volunteer)

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