Flutter onbackgroundmessage not working

Query: flutter onBackgroundMessage not working

When the onBackgroundMessage handler in Flutter is not working, it can be due to various reasons. Let’s explore some possible explanations and examples:

Possible Causes:

1. No Firebase Messaging Plugin: The onBackgroundMessage handler is specifically used for handling background messages in flutter_local_notifications plugin combined with the Firebase Messaging plugin. Make sure you have added the Firebase Messaging plugin to your Flutter project.
2. Incorrect Implementation: Ensure that you have implemented the onBackgroundMessage handler correctly in your code. Here is an example:

import 'package:flutter_local_notifications/flutter_local_notifications.dart';
import 'package:firebase_messaging/firebase_messaging.dart';

Future _firebaseMessagingBackgroundHandler(RemoteMessage message) async {
  await Firebase.initializeApp();
  print('Handling a background message: ${message.messageId}');
}

void main() {
  FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
      FlutterLocalNotificationsPlugin();

  const AndroidInitializationSettings initializationSettingsAndroid =
      AndroidInitializationSettings('app_icon');

  final InitializationSettings initializationSettings =
      InitializationSettings(android: initializationSettingsAndroid);

  flutterLocalNotificationsPlugin.initialize(initializationSettings,
      onSelectNotification: (String? payload) async {}); // Add this line if necessary

  FirebaseMessaging.onBackgroundMessage(_firebaseMessagingBackgroundHandler);

  runApp(MyApp());
}
    

3. Not Running in Background: Background handling requires the app to be running in the background. If the app is not running in the background, onBackgroundMessage won’t be triggered. You can test this by running the app on a physical device and then switching to another app or locking the device screen.
4. Permissions: Verify that you have set up the necessary permissions for receiving notifications in the AndroidManifest.xml file. Here is an example:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.your_app">

    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
    <uses-permission android:name="android.permission.WAKE_LOCK" />
  
    <application
        android:name=".Application"
        ...
    >
        ...
        <receiver android:name="com.dexterous.flutterlocalnotifications.ScheduledNotificationBootReceiver">
            <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED" />
            </intent-filter>
        </receiver>
        <receiver android:name="com.dexterous.flutterlocalnotifications.ScheduledNotificationReceiver">
            <intent-filter>
                <action android:name="com.dexterous.flutterlocalnotifications.SCHEDULE_NOTIFICATION" />
            </intent-filter>
        </receiver>
  
    </application>

</manifest>
    

5. Other Factors: There could be other factors such as conflicts with other plugins or outdated versions, so it’s essential to ensure you have the latest versions of the plugins and dependencies in your project. Troubleshoot any conflicts and follow the documentation and examples provided by the plugin maintainers.

By considering these possible causes and implementing the necessary steps, you should be able to resolve the issue with onBackgroundMessage not working in Flutter.