Develop Reference

Android - push notifications: purpose of FirebaseMessagingService class?

I've seen two tutorials about sending push messages from server with PHP to android devices through firebase cloud messaging and it works fine. But both tutorials have the FirebaseMessagingService class and I don't understand what's the purpose of it?? They don't explain a bit about it.
This is it:
class FirebaseMessagingService : com.google.firebase.messaging.FirebaseMessagingService() {
override fun onMessageReceived(remoteMessage: RemoteMessage?) {
showNotification(remoteMessage!!.data["message"]!!)
}
private fun showNotification(message: String) {
val i = Intent(this, MainActivity::class.java)
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)
val pendingIntent = PendingIntent.getActivity(this, 0, i, PendingIntent.FLAG_UPDATE_CURRENT)
val builder = NotificationCompat.Builder(this)
.setAutoCancel(true)
.setContentTitle("FCM Test")
.setContentText(message)
.setSmallIcon(R.drawable.common_google_signin_btn_icon_dark)
.setContentIntent(pendingIntent)
val manager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
manager.notify(0, builder.build())
}
}
Can I send push notifications from android with it? I just need to send push messages from PHP so can I delete it? The overview of my project is already messy and hard to follow and I don't want any useless stuff in there. Thanks in advance

This class is responsible for handling income message. The function onMessageReceived will be invoked when there is incoming data message no matter your app is in foreground or background. More specifically, this method is for you to customize the handling of key:value pair in data payload
You can leave it there if you are not going to do any special handling.
Please read here for more information.

Force Grouping of Notifications?

According to the Notification Design Guidelines documentation:
If the same app sends four or more notifications and does not specify a grouping, the system automatically groups them together.
So I tested this out:
However, it only works when you have 4 or more notifications. I notice Messenger does this when you only have two notifications:
So my question is, can I tell the Android to always group my notifications like Messenger does? Or does Messenger use the setGroup() method that I would prefer not to use...

It's doable.
The concept is to make a group notification builder for grouping up notifications and apply same groupKey to other notification builder. And call NotificationManagerCompat.notify() to build group notification beforehand. So these notifications with same groupKey will group together.
You can add group notification builder with NotificationCompat.Builder.setGroup("GROUP_KEY") and NotificationCompat.Builder.setGroupSummary(true).
And add NotificationCompat.Builder.setGroup("GROUP_KEY") to other notifications.
val groupKey = "GROUP_KEY"
val groupBuilder = NotificationCompat.Builder(context, "CHANNEL_ID")
groupBuilder.apply {
setAutoCancel(true)
...
setGroupSummary(true)
setGroup(groupKey)
}
val builder = NotificationCompat.Builder(context, "CHANNEL_ID")
groupBuilder.apply {
setAutoCancel(true)
...
setGroup(groupKey)
}
val notificationManager = NotificationManagerCompat.from(context)
notificationManager.notify(NOTIFICATION_ID, groupBuilder.build())
notificationManager.notify(NOTIFICATION_TAG, NOTIFICATION_ID, builder.build())

How to prevent Android notifications from overwriting themselves?

I am using XMPP (smack) to create a messaging application and I am sending notifications whenever I receive a new message. The problem is that if I receive messages from two different users I can only see the last notification. How can I change it? Here is my code.
Intent thisIntent = new Intent(mApplicationContext, ChatActivity.class);
thisIntent.putExtra("EXTRA_CONTACT_JID",contactJid);
PendingIntent contentIntent = PendingIntent.getActivity(mApplicationContext, 0, thisIntent, PendingIntent.FLAG_UPDATE_CURRENT);
NotificationCompat.Builder b = new NotificationCompat.Builder(mApplicationContext);
b.setAutoCancel(true)
.setDefaults(Notification.DEFAULT_ALL)
.setWhen(System.currentTimeMillis())
.setSmallIcon(R.drawable.fab_bg_mini)
.setTicker("Hearty365")
.setContentTitle("New message")
.setContentText(" You received a new message from " + contactJid)
.setContentIntent(contentIntent)
.setContentInfo("Info");
if(!ChatActivity.active){
b.setDefaults(Notification.DEFAULT_LIGHTS| Notification.DEFAULT_SOUND);
}
NotificationManager notificationManager = (NotificationManager) mApplicationContext.getSystemService(Context.NOTIFICATION_SERVICE);
notificationManager.notify(1, b.build());
And as you can see I put an extra contactJid which is important to me. I need to set it in such a way that if a user clicks one notification its contactJid will be this and if another its contactJid will be another.

notificationManager.notify(1, b.build()); is your problem - you need to supply a unique identifier for this notification, as per the documentation:
If a notification with the same id has already been posted by your application and has not yet been canceled, it will be replaced by the updated information.
You are supplying the constant 1 for each notification, instead of a unique ID. I'd suggest using a hash of the contact JID (which I assume is a string):
notificationManager.notify(contactJid.hashCode(), b.build());

real time notification by JSON format in android

i have an application about football/soccer , i'm using API for get information about the matches, i need a way to make a real time notification when a goal is added in this API which have a JSON format .

If you have access to your back end web service code, look into Google cloud messaging(gcm) service, it is made precisely for this purpose. If it is not feasible to use gcm, you need to set a repeating alarm, but it will not be as accurate as gcm. But I highly recommend going for gcm. Here's a link for your reference. GCM dev docs
Another work around for the case where you don't have access to source code for back end is to develop a middle layer sort of web service that keeps polling your back end and uses gcm to alert the clients. This way atleast you won't be wasting user's system resources.

This is how you pop a notification:
Uri defaultSoundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this)
.setSmallIcon(R.drawable.logo_notification)
.setContentTitle(title)
.setContentText(body)
.setAutoCancel(true)
.setSound(defaultSoundUri)
.setVibrate(new long[] { 200, 200, 200})
.setContentIntent(pendingIntent);
NotificationManager notificationManager =
(NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
notificationManager.notify(id, notificationBuilder.build()); //id is the notification id, if you use the same id, the notification will override the previous

In order to achieve the functionality,
Use a service to frequently(maybe once in 5 minutes) check information about the match.
If you have any Updates, show a notification to the user.
To show Notification:
PendingIntent pi = PendingIntent.getActivity(getApplicationContext(), 0, new Intent(), 0);
Notification notification = new NotificationCompat.Builder(getApplicationContext()).setTicker("Ticker Text").setSmallIcon("Icon").setContentTitle("Title").setContentText("Content Text").setContentIntent(pi).setAutoCancel(true).build();
NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
notificationManager.notify(0, notification);
For more info use this link
here

What you really want to do is have a Receiver that will run and check for updates. For real time updates, I would use a Socket.
It pretty much depends on your server.

How to make push notification without internet

me and my colleague are trying to show "push notification" message in mobile device. Colleague is telling that it can´t be done without Google Cloud Messaging but I think - why use any server for that?
We want something like this:
How our application will work is:
- user has app on background
- ajax request is made (request to our server)
- server response is: You have 1 new message
- message is showed in top strip on mobile.
Of course, the message can be showed without internet.. My GF had mobile app "Pou"... when he pooped notification was displayed... Just I dont get it why to use any Google service for that?
Can somebody direct me pls?

You should use Notification to show "push notification".
private void showNotification() {
Intent notificationIntent = new Intent(this, MainActivity.class);
NotificationCompat.Builder builder = new NotificationCompat.Builder(this)
.setSmallIcon(R.drawable.ic_launcher)
.setAutoCancel(true)
.setTicker(getString(R.string.notification_ticker_text))
.setContentText(getString(R.string.notification_content_text))
.setContentIntent(PendingIntent.getActivity(this, 0, notificationIntent, 0))
.setWhen(System.currentTimeMillis())
.setContentTitle(getString(R.string.app_name))
.setDefaults(Notification.DEFAULT_ALL);
Notification notification = builder.build();
((NotificationManager) this.getSystemService(NOTIFICATION_SERVICE)).notify(0, notification);
}