[firebase_messaging] Why not use FirebaseMessagingService#onMessageReceived for receiving messages?

[yorihutagalung]

Hello everyone,

Does anyone know why firebase_messaging (Android) uses BroadcastReceiver instead of FirebaseMessagingService#onMessageReceived to receive messages?

According to the Android official documentation, it states that we should use FirebaseMessagingService, and I couldn’t find any reference to the BroadcastReceiver approach.

My company is currently investigating a low notification receive rate on our flutter app compared to our native app, even though both use FCM to send notifications (via the same backend system). After reviewing the native implementation, we noticed this discrepancy and are wondering if this could be the reason why our flutter app has a lower receive rate.

Any explanation would be greatly appreciated. Thank you!

[amrnabih113]

Actually, Flutter doesn’t skip FirebaseMessagingService , the plugin still uses it under the hood.
The reason you see a BroadcastReceiver is because Flutter has to deliver the message from Android into the Dart world. On native Android, you can just override onMessageReceived() and you’re done, but in Flutter the Dart runtime might not even be running (for example, when the app is in the background or killed).

That’s where the BroadcastReceiver comes in: it catches the FCM message, then spins up a background Dart isolate and forwards the message to your Dart handler. It’s basically just a bridge between Android and Flutter.