Develop Reference

How to register push notification receiver in the background in NativeScript-Vue

I'm working on a NativeScript-Vue mobile app and I want to register a push notifications receiver in the background so that when the server sends push notifications I can show them to the user even when the app is not running in the foreground. What is the best way to accomplish that on both Android and iOS?
Any recommendations or help would be much appreciated
I tried using "nativescript-background-fetch" library but couldn't figure out the requirements to make it work.
I'm using "nativescript-pusher" library to start a broadcast receiver in the foreground.
I expect to register a broadcast receiver in the background, and whenever the server sends a broadcast, the app should receive the message and act accordingly (show a notification in my case)

Firebase Messaging Android Notification not received when app is open

I configured my Android app as the Firebase docs and I am receiving notifications normally, however when the app is in the foreground I do not get any notifications. Is there a way to get the notifications even if the app is in the foreground.

if you have done all the steps as given in the docs then when your app is in foreground your "sendNotification()" is not called, which is responsible for showing the notification. If you want notification when app is in foreground then just sendNotification() inside the onMessageReceived()
for more check this link
https://github.com/firebase/quickstart-android/blob/master/messaging/app/src/main/java/com/google/firebase/quickstart/fcm/MyFirebaseMessagingService.java

Push notification for apps that are not running?

I'm studying GCM now and as far as I see it works for running apps, passing a payload to them and letting the app to deal with it by itself.
However, I've seen apps that are received notifications (or maybe it was Android receiving and showing notification related to the app) when not running. For example, device was turned off. I'm just turning the device on, then turning on Wi-Fi and after a second I see new notifications with the app's icon on it and some text related to in-app events.
How could I implement that kind of notifications?

declare the Broadcast Receiver and the GCMIntentService in the mainfest will allow the Application to get any Message (GCM Included of crouse) if the application not running
BroadcastReceiver
Example and Documantion

For being able to receive GCM's push notifications while the app isn't running you should set up an android IntentService, make it run in the background and set the BroadcastReceiver to listen for GCM notifications.
For more information refer to Google's documentation: GCM information

Check UrbanAirship. I'm using it no my android app.

How are Android GCM push notifications processed?

I am working on a Cordova Android app that handles push notifications using the PushPlugin. The app will correctly receive push notifications when the app is open. However no push notifications are received (or at least handled) if the app is not open.
This makes some sense given that the plugin has code that specifically handles receiving push notifications. What does not make much sense to me is why this code even exists at all. Before building this app, I assumed that the OS had some sort of queuing system that received any/all notifications.
Does a notification queue exists in Android that handles push notifications for all apps or does each app need to handle the notifications on their own.
Can Android apps process push notifications while closed?
Can Cordova Android apps process push notifications while closed?

In Google Cloud Messaging (which is the push notifications mechanism used by the PushPlugin) each application decides how to handle the notification. When a push notification arrives to the device, GCM triggers a BroadcastReceiver in the recipient application, and the application is responsible for handling the notification data.
Android apps can process push notifications when closed unless they are explicitly stopped by the user (in which case no notifications will reach the app until it is restarted again by the user). If they leave the foreground by the user switching to another app or going to the home screen, the can still receive and process notifications.
Yes. According to the PushPlugin you posted a link to, it seems that they can. When the app is not in the foreground, the notification is handled differently - a notification is added to the notification bar, and when it is tapped, it should open the app.

With PushPlugin, when sending push notifications to GCM (for GCM to send them to the device) one has to include a msgcnt key value pair after the message key value pair in the payload value in the JSON message, like this:
{
"GCM":"{\"data\":{\"message\":\"hello\",\"msgcnt\":\"1\"}}"
}
or else PushPlugin will not handle the notification when the app is in the background. It has to do with the way the GCMIntentService.java file is written in the plugin.

Receiving GCM Android Notifications while App is not Running

I'm confused by the GCM documentation in how to receive a notification on a client device when the app I'm developing is not running. I've tried googling and reading stackoverflow on this topic, but I haven't gotten complete clarification yet.
Do I just extend GCMBaseIntentService to receive notifications, add the service name to my manifest file, and then my service that extended GCMBaseIntentService will automatically handle notifications to my app, even when the app itself is not running? Is there anything else I need to do?
Thanks!
P.S. I found a thread with a similar title, but it doesn't seem to be the same question.

From doc :-
An Android application on an Android device doesn't need to be running
to receive messages. The system will wake up the Android application
via Intent broadcast when the message arrives, as long as the
application is set up with the proper broadcast receiver and
permissions.
Then what is confusion here?