Broadcast in GCM:

onMessageReceived method:

Intent intent = new Intent(MessageReceiver.name);
sendBroadcast(intent);

Create class Reciever:

public class MessageReceiver extends BroadcastReceiver{
    public static String name = "com.app.privilege.receiver.MESSAGE";
    @Override    public void onReceive(Context context, Intent intent) {

    }
}

In MainActivity:

Above Oncreate
MessageReceiver receiver = new MessageReceiver() {
    @Override    public void onReceive(Context context, Intent intent) {
        displayData();
    }
};

In Oncreate:

registerReceiver(receiver, new IntentFilter("com.app.privilege.receiver.MESSAGE"));

public void displayData() {
    adapter.notifyDataSetChanged();
    recyclerView.invalidate();
}


On Destroy:
@Overrideprotected void onDestroy() {
    super.onDestroy();
    unregisterReceiver(receiver);
}

In Manifest:

<receiver    android:name=".receiver.MessageReceiver"    android:enabled="true">
    <intent-filter>
        <action android:name="com.app.privilege.receiver.MESSAGE" />
    </intent-filter>
</receiver>