android - How to stack Firebase Cloud Messaging notifications when the application is not running?

Question

I am using Firebase Cloud Messaging to send push notifications from my server to my android application.

When the application is running, the notifications are stacked because I set them to a group in my FirebaseMessagingService. Which is nice.

However, when the application is not running, the notifications are not stacked and each one appears individually. Which is not nice.

How to make sure notifications are stacked even when the application is not running?

This is how my FirebaseMessagingService looks like:

public class MyFcmListenerService extends FirebaseMessagingService {

    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        RemoteMessage.Notification notification = remoteMessage.getNotification();

        Uri defaultSoundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
        NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this)

                .setSmallIcon(R.drawable.notif_white)
                .setLargeIcon(BitmapFactory.decodeResource(getApplicationContext().getResources(), R.drawable.notif_white))
                .setContentTitle(getResources().getString(R.string.app_name))
                .setContentText(notification.getBody())
                .setAutoCancel(true)
                .setPriority(2)
                .setSound(defaultSoundUri)
                .setContentIntent(pendingIntent)
                .setGroup("1")
                .setGroupSummary(true)
                .setOnlyAlertOnce(true);


        NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        notificationManager.notify(0 , notificationBuilder.build());

        }
    }

Answer 1

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