Should you need access to the raw push messages to process some custom logic around the data in the push, you can obtain it by either registering a PushMessageListener when initializing the SDK, or the System Tray Intent used to open Launcher Activity.

App state	Notification	Data	Both
Foreground	PushMessageListener	PushMessageListener	PushMessageListener
Background	System tray	PushMessageListener	Notification: system tray; Data: in extras of the intent.

PushMessageListeners simply redirects messages from internally registered FirebaseMessagingService .

Learn more in the Firebase documentation.

📘
Deep links
If a push notification is delivered while the app is in the foreground, you can build your own deep link in the onMessageReceived() method that creates a link to a particular activity in your app.

public class PushHandler implements PushMessageListener {

    @Override
    public void onMessageReceived(RemoteMessage message) {
      // Check if message contains a notification payload.
        if (message.getNotification() != null) {
        Log.i("TAG", "Push notification: " + message.getNotification().getBody());
      // Do something with the message to notify the user
          // Example
          createNotificationChannel(context);
          Notification.Builder b = new Notification.Builder(context);
          b.setAutoCancel(true)
            .setDefaults(NotificationCompat.DEFAULT_ALL)
            .setWhen(System.currentTimeMillis())
            .setSmallIcon(R.drawable.common_google_signin_btn_icon_dark)
            .setContentTitle("foreground message")
            .setContentText(body)
            .setContentInfo("INFO");
          if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            b.setChannelId("test_channel_id1");
          }
          NotificationManager nm = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
          nm.notify(1, b.build());
        }
    }
}

private void createNotificationChannel(Context context) {
        // Create the NotificationChannel, but only on devices that have the Google API 26+ because the NotificationChannel class is new and not in supported in older libraries
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            CharSequence name = "test channel";
            String description = "some description";
            int importance = NotificationManager.IMPORTANCE_DEFAULT;
            NotificationChannel channel = new NotificationChannel("test_channel_id1", name, importance);
            channel.setDescription(description);
            // Register the channel with the system; you can't change the importance
            // or other notification behaviors after this
            NotificationManager notificationManager = context.getSystemService(NotificationManager.class);
            notificationManager.createNotificationChannel(channel);
        }
}

Pass your class to the pushMessageListener() on the ComapiConfig object:

config.pushMessageListener(new PushHandler());