When use flutter_local_notifications with firebase message on ios 18 get push notification twice

[Nak-2000]

Describe the bug
since the ios18 release there's some issue with push notification twice when I use flutter local notification function inside FirebaseMessaging.onMessage.listen() function. and it's only happen to ios18 device (even after firebase has already fix the notification twice but the local notification still push twice).

Expected behavior
I would expect the notification to only push once.

Sample code to reproduce the problem

var initializationSettingsAndroid = const AndroidInitializationSettings('@mipmap/ic_launcher');
var initializationSettingsIOS = const DarwinInitializationSettings(
defaultPresentAlert: true,
);

var initializationSettings = InitializationSettings(android: initializationSettingsAndroid, iOS: initializationSettingsIOS);
await flutterLocalNotificationsPlugin.initialize(initializationSettings, onDidReceiveNotificationResponse: (response) async {

print("onDidReceiveNotificationResponse:");
selectNotificationSubject.add(response.payload!);
print("onDidReceiveNotificationResponse: ${response.payload}");

});

FirebaseMessaging.onMessage.listen((RemoteMessage remoteMessage) {
var message = remoteMessage.data;
print("onMessage==>: listen $message");
appNotification = AppNotification(
id: message['id'],
type: message['type'],
title: message['title'],
content: message['content'],
referenceId: message['reference_id'],
screenDetail: message['detail_screen'],
);
_showNotification(appNotification);
});

Future _showNotification(AppNotification? appNotification) async {
try {
const AndroidNotificationDetails androidPlatformChannelSpecifics = AndroidNotificationDetails(
'default_channel_id',
'your_channel_name',
channelDescription: 'your_channel_description',
importance: Importance.max,
priority: Priority.high,
showWhen: false,
);

  const NotificationDetails platformChannelSpecifics = NotificationDetails(android: androidPlatformChannelSpecifics);
  await flutterLocalNotificationsPlugin.show(
    1,
    "${appNotification!.title}",
    "${appNotification.content}",
    platformChannelSpecifics,
    payload: jsonEncode(appNotification),
  );
} on Exception catch (e) {
  log("show notification error $e");
}

}

[Levi-Lesches]

Are you sure firebase isn't also trying to show a notification? In that case you'd get the first notification from fcm and then another one from this package. Try commenting out the call to show() and see if you get 0, 1, or 2 notifications

[bbader-kada]

Yes same problem for me.

FirebaseMessaging.onMessage.listen(_onMessage); - triggers twice. So when the flutterLocalNotificationsPlugin.show is commented out then nothing will happen.

[Levi-Lesches]

Interesting. If you can demonstrate that it's firebase triggering twice and not an issue with this package, I'd recommend we close this issue and open one on firebase_messaging instead.

One way to demonstrate this would be to use shared preferences to set a flag, but check if it's already set. If firebase is really triggering twice, you should only be able to set the flag, and show a notification, once.

Please let us know if you try this

[SomaPrasanna4037]

In ios only it will trigger twice, we can check platform.isAndroid flag to call this method flutterLocalNotificationsPlugin.show