Group fcm message from every chat room separately - firebase-cloud-messaging

Question

I have already succeeded to send/receive from/to group fcm
the problem is:
I need to collect the message coming from the same group together Like Facebook Messenger :
Application Name,then chat room name,then messages from the same room
*
Example : I need instead of the current
separated messages in attached photo:
Learning ways <<the name of app
num2 <<room name
Mon: 6 <<message1
Mon: 7 <<message2
Mon: 8 <<message3
Current Notifications Call:
#RequiresApi(api = Build.VERSION_CODES.KITKAT_WATCH)
private void showOreoNotification() {
OreoNotification oreoNotification = new OreoNotification(this);
Notification.Builder builder = oreoNotification.getOreoNotification(title, sender_name + body, pendingIntent,
defaultSound, icon).setLargeIcon(senderImages);
oreoNotification.getManager().notify(i, builder.build());
i++;
}
private void showOLdNotifications() {
assert icon != null;
NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this)
.setSmallIcon(Integer.parseInt(icon))
.setContentTitle(title)
.setContentText(sender_name + body)
.setAutoCancel(true)
.setSound(defaultSound)
.setContentIntent(pendingIntent).setLargeIcon(senderImages);
NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
assert notificationManager != null;
notificationManager.notify(i, notificationBuilder.build());
i++;
}

Answer 1

You can use InboxStyle for Android 4.1+
Message format:
val str1:String = "%s : %s".format(sender, message)
InboxStyle:
Notification notif = new Notification.Builder(mContext)
.setContentTitle(room_name)
.setContentText(subject)
.setSmallIcon(R.drawable.icon)
.setLargeIcon(aBitmap)
.setStyle(new Notification.InboxStyle()
.addLine(str1)
.addLine(str2)
.setContentTitle("")
.setSummaryText("+1 more"))
.build();
You can use MessagingStyle for Android 7+
var notification = NotificationCompat.Builder(this, CHANNEL_ID)
.setStyle(NotificationCompat.MessagingStyle("me")
.setConversationTitle(room_name)
.addMessage(message1, timestamp1, null) // Pass in null for you.
.addMessage(message2, timestamp2, user2)
.addMessage(message3, timestamp3, user3)
.build()