[firebase_messaging] <Background push notification handling - no implementation found for method FcmDartService#initialized>

[urbanjagodic]

Occurrence of MissingPluginException(No implementation found for method FcmDartService#initialized)

Recently I have updated FCM plugin for flutter to 5.1.5 version that supports
handling of background push notifications. I have followed the instructions
to implement and incorporate it into my application, but handling still fails.
Every time when I try to interact with a push notification on device, from onResume or onLaunch state, plugin fails and I receive this error:

> E/MethodChannel#plugins.flutter.io/firebase_messaging(19582): Failed to handle method call
E/MethodChannel#plugins.flutter.io/firebase_messaging(19582): java.lang.IllegalStateException: registrar.activity() must not be null
E/MethodChannel#plugins.flutter.io/firebase_messaging(19582): 	at com.apptreesoftware.barcodescan.BarcodeScanPlugin$Companion.registerWith(BarcodeScanPlugin.kt:19)
E/MethodChannel#plugins.flutter.io/firebase_messaging(19582): 	at com.apptreesoftware.barcodescan.BarcodeScanPlugin.registerWith(Unknown Source:2)
E/MethodChannel#plugins.flutter.io/firebase_messaging(19582): 	at io.flutter.plugins.GeneratedPluginRegistrant.registerWith(GeneratedPluginRegistrant.java:28)
E/MethodChannel#plugins.flutter.io/firebase_messaging(19582): 	at example.app.myapp.Application.registerWith(Application.kt:18)
E/MethodChannel#plugins.flutter.io/firebase_messaging(19582): 	at io.flutter.plugins.firebasemessaging.FlutterFirebaseMessagingService.startBackgroundIsolate(FlutterFirebaseMessagingService.java:164)
E/MethodChannel#plugins.flutter.io/firebase_messaging(19582): 	at io.flutter.plugins.firebasemessaging.FirebaseMessagingPlugin.onMethodCall(FirebaseMessagingPlugin.java:133)
E/MethodChannel#plugins.flutter.io/firebase_messaging(19582): 	at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(MethodChannel.java:222)
E/MethodChannel#plugins.flutter.io/firebase_messaging(19582): 	at io.flutter.embedding.engine.dart.DartMessenger.handleMessageFromDart(DartMessenger.java:96)
E/MethodChannel#plugins.flutter.io/firebase_messaging(19582): 	at io.flutter.embedding.engine.FlutterJNI.handlePlatformMessage(FlutterJNI.java:643)
E/MethodChannel#plugins.flutter.io/firebase_messaging(19582): 	at android.os.MessageQueue.nativePollOnce(Native Method)
E/MethodChannel#plugins.flutter.io/firebase_messaging(19582): 	at android.os.MessageQueue.next(MessageQueue.java:326)
E/MethodChannel#plugins.flutter.io/firebase_messaging(19582): 	at android.os.Looper.loop(Looper.java:160)
E/MethodChannel#plugins.flutter.io/firebase_messaging(19582): 	at android.app.ActivityThread.main(ActivityThread.java:6863)
E/MethodChannel#plugins.flutter.io/firebase_messaging(19582): 	at java.lang.reflect.Method.invoke(Native Method)
E/MethodChannel#plugins.flutter.io/firebase_messaging(19582): 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:537)
E/MethodChannel#plugins.flutter.io/firebase_messaging(19582): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
E/flutter (19582): [ERROR:flutter/lib/ui/ui_dart_state.cc(148)] Unhandled Exception: PlatformException(error, registrar.activity() must not be null, null)
E/flutter (19582): #0      StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:564:7)
E/flutter (19582): #1      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:316:33)
E/flutter (19582): <asynchronous suspension>
E/flutter (19582): #2      FirebaseMessaging.configure (package:firebase_messaging/firebase_messaging.dart:118:16)
E/flutter (19582): #3      PushNotificationReceiver.handleReceivedPushNotification (package:panda/utils/push_notification_receiver.dart:57:26)
E/flutter (19582): #4      _MainNavigationState.build (package:panda/navigation/main_navigation.dart:116:30)
E/flutter (19582): #5      StatefulElement.build (package:flutter/src/widgets/framework.dart:4012:27)
E/flutter (19582): #6      ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3924:15)
E/flutter (19582): #7      Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
E/flutter (19582): #8      ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
E/flutter (19582): #9      StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11)
E/flutter (19582): #10     ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
E/flutter (19582): #11     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
E/flutter (19582): #12     Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
E/flutter (19582): #13     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
E/flutter (19582): #14     Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
E/flutter (19582): #15     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
E/flutter (19582): #16     ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
E/flutter (19582): #17     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
E/flutter (19582): #18     Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
E/flutter (19582): #19     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14)
E/flutter (19582): #20     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
E/flutter (19582): #21     Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
E/flutter (19582): #22     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14)
E/flutter (19582): #23     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
E/flutter (19582): #24     Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
E/flutter (19582): #25     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14)
E/flutter (19582): #26     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
E/flutter (19582): #27     Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
E/flutter (19582): #28     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
E/flutter (19582): #29     Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
E/flutter (19582): #30     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
E/flutter (19582): #31     StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11)
E/flutter (19582): #32     ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
E/flutter (19582): #33     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
E/flutter (19582): #34     Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
E/flutter (19582): #35     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
E/flutter (19582): #36     Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
E/flutter (19582): #37     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
E/flutter (19582): #38     StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11)
E/flutter (19582): #39     ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
E/flutter (19582): #40     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
E/flutter (19582): #41     Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
E/flutter (19582): #42     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14)
E/flutter (19582): #43     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
E/flutter (19582): #44     Element.updateChild (package:flutter/src/widget
E/flutter (19582): [ERROR:flutter/lib/ui/ui_dart_state.cc(148)] **Unhandled Exception: MissingPluginException(No implementation found for method FcmDartService#initialized on channel plugins.flutter.io/firebase_messaging_background)**
E/flutter (19582): #0      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:314:7)
E/flutter (19582): <asynchronous suspension>
E/flutter (19582): #1      _fcmSetupBackgroundChannel (package:firebase_messaging/firebase_messaging.dart:50:21)
E/flutter (19582): #2      _AsyncAwaitCompleter.start (dart:async-patch/async_patch.dart:49:6)
E/flutter (19582): #3      _fcmSetupBackgroundChannel (package:firebase_messaging/firebase_messaging.dart:23:32)
E/flutter (19582): #4      _runMainZoned.<anonymous closure>.<anonymous closure> (dart:ui/hooks.dart:216:25)
E/flutter (19582): #5      _rootRun (dart:async/zone.dart:1124:13)
E/flutter (19582): #6      _CustomZone.run (dart:async/zone.dart:1021:19)
E/flutter (19582): #7      _runZoned (dart:async/zone.dart:1516:10)
E/flutter (19582): #8      runZoned (dart:async/zone.dart:1500:12)
E/flutter (19582): #9      _runMainZoned.<anonymous closure> (dart:ui/hooks.dart:208:5)
E/flutter (19582): #10     _startIsolate.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:301:19)
E/flutter (19582): #11     _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:172:12)
E/flutter (19582): 

Here are my Application.kt and MainActivity kotlin classes:

Application.kt

package example.app.myapp

import io.flutter.app.FlutterApplication
import io.flutter.plugin.common.PluginRegistry
import io.flutter.plugin.common.PluginRegistry.PluginRegistrantCallback
import io.flutter.plugins.GeneratedPluginRegistrant
import io.flutter.plugins.firebasemessaging.FlutterFirebaseMessagingService

class Application : FlutterApplication(), PluginRegistrantCallback {

  override fun onCreate() {
    super.onCreate()
    FlutterFirebaseMessagingService.setPluginRegistrant(this)
  }

  override fun registerWith(registry: PluginRegistry) {
    GeneratedPluginRegistrant.registerWith(registry)
  }
}

MainActivity.kt:

package example.app.myapp

import android.os.Bundle

import io.flutter.plugins.GeneratedPluginRegistrant
import android.view.WindowManager.LayoutParams
import io.flutter.app.FlutterFragmentActivity

class MainActivity: FlutterFragmentActivity() {
  override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    GeneratedPluginRegistrant.registerWith(this)
    getWindow().addFlags(LayoutParams.FLAG_SECURE)
  }
}

[anatter]

same issue here

[kevmax1]

Please any one have solution for this issue ?

[mohmdezeldeen]

same issue here ..

[divan]

So in the new firebase_messaging version, support for background messages was added. Actually, if you don't add background message handler, it failed to work on Android for me, so I added handler, according to docs:

_fcm.configure(
	...
	onBackgroundMessage: myBackgroundMessageHandler,
	...
)

Now, if you run code with background handler on iOS, it explodes with the error in this issue. So the solution is to set the handler to null for iOS:

_fcm.configure(
	...
	onBackgroundMessage: Platform.isIOS ? null : myBackgroundMessageHandler,
	...
)

This solved the problem for me.

[urbanjagodic]

So in the new firebase_messaging version, support for background messages was added. Actually, if you don't add background message handler, it failed to work on Android for me, so I added handler, according to docs:

_fcm.configure(
	...
	onBackgroundMessage: myBackgroundMessageHandler,
	...
)

Now, if you run code with background handler on iOS, it explodes with the error in this issue. So the solution is to set the handler to null for iOS:

_fcm.configure(
	...
	onBackgroundMessage: Platform.isIOS ? null : myBackgroundMessageHandler,
	...
)

This solved the problem for me.

It still throws the same error output. Receiving push notifications when app is active works fine, it fails only in onResume and onLaunch states.

How have you implemented Application and MainActivity classes?

[urbanjagodic]

Ok, it appears that that the issue was with notification data payload message, not with the
code implementation itself.

I just added

"data" : {
     "body" : "example body data",
     "title" : "example title data",
     "click_action": "FLUTTER_NOTIFICATION_CLICK",
 }

to notification message payload and now it works for both onResume and onLaunch states.

[alvinotienokelly]

So in the new firebase_messaging version, support for background messages was added. Actually, if you don't add background message handler, it failed to work on Android for me, so I added handler, according to docs:

_fcm.configure(
	...
	onBackgroundMessage: myBackgroundMessageHandler,
	...
)

Now, if you run code with background handler on iOS, it explodes with the error in this issue. So the solution is to set the handler to null for iOS:

_fcm.configure(
	...
	onBackgroundMessage: Platform.isIOS ? null : myBackgroundMessageHandler,
	...
)

This solved the problem for me.

but when i try to use onBackground message it says that it is an unknown parameter.

[divan]

@urbanjagodic, yes, that one is super easy to overlook too. Overall, for people who don't have prior experience with firebase messaging on Android, I feel like tons are default assumptions go wrong with using this plugin.
I also spent weeks(!) before realized that I need to add "FLUTTER_NOTIFICATION_CLICK" to the push notification payload (which still doesn't make much sense to me). Yet, it's in the README (not sure if I overlooked it at the beginning, or it's just you would never assume such thing to be required).

@alvinotienokelly, did you update your firebase_messaging plugin to the latest version?

Actually, I had to remove onBackgroundMessage handler completely, because it was causing SIGSEGV crash on Android (which cause wasn't obvious), and after spending a week debugging it I removed it waiting for the more stable code. (there a plenty of issues on this crash in both flutterfire and flutter repositories)