Update Push Notification Android

Question

I am implementing push notifications on Android. The problem comes when I want to update my notifications. I would like to stack up notifications so that if a notification is visible I simply update it and do this.

mNotifyBuilder.setContentText(currentText)
    .setNumber(++numMessages);

But every time I receive a notification ++numMessages is set back to 0 before being summed up. I need it to sum up from where it was left if there is a notification on the screen. Here is the code:

//Class is extending GcmListenerService
public class GCMPushReceiverService extends GcmListenerService {

    //variables for message 1,on receiving job applications
    String name;
    String lastname;
    String jobtypename;
    String kasualjobdatetimepostedat;
    String kasualjobcount;
    int numMessages;

    //This method will be called on every new message received
    @Override
    public void onMessageReceived(String from, Bundle data) {
        //Getting the message from the bundle
        String message = data.getString("message");
        String messageid = data.getString("messageid");

        if(messageid.compareTo("1")==0){
            name=data.getString("firstname");
            lastname=data.getString("lastname");
            jobtypename=data.getString("jobtype");
            kasualjobdatetimepostedat=data.getString("kasualjobdatetimepostedat");
        }
        else
        {
            kasualjobcount=data.getString("kasualjobcount");
        }
            //Displaying a notification with the message
        sendNotification(message, messageid);
    }

    //This method is generating a notification and displaying the notification
    private void sendNotification(String message,String messageid) {
        Intent intent = new Intent(this, Main_Activity.class);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        int requestCode = 0;
        PendingIntent pendingIntent = PendingIntent.getActivity(this, requestCode, intent, PendingIntent.FLAG_ONE_SHOT);
        Uri sound = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);

        Log.d("notificationid", String.valueOf(messageid));
        if(messageid.compareTo("2")==0) {//messages to do with jobs around 2
            String messageionkasualjobscount="There are "+kasualjobcount+" new jobs around you";
            NotificationCompat.Builder noBuilder = new NotificationCompat.Builder(this);
            noBuilder.setSmallIcon(R.mipmap.ic_launcher)
                    .setContentTitle("KasualJobs2")
                    .setContentText(messageionkasualjobscount)
                    .setAutoCancel(true)
                    .setContentIntent(pendingIntent).setSound(Settings.System.DEFAULT_NOTIFICATION_URI);

            NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
            notificationManager.notify(2, noBuilder.build()); //messageid = ID of notification
        }else{//messages to with users applying for job 1

            String messageionkasualjobapplication=name+ " "+ lastname+" has applied for the "+jobtypename+" you posted on "+kasualjobdatetimepostedat;
            NotificationCompat.Builder noBuilder = new NotificationCompat.Builder(this);
            noBuilder.setSmallIcon(R.mipmap.ic_launcher)
                    .setContentTitle("KasualJobs1")
                    .setContentText(messageionkasualjobapplication)
                    .setAutoCancel(true).setNumber(++numMessages)
                    .setContentIntent(pendingIntent).setSound(Settings.System.DEFAULT_NOTIFICATION_URI);

            NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
            notificationManager.notify(1, noBuilder.build()); //messageid = ID of notification

        }
    }

}

Answer 1

In general, you should not expect your field values to persist across multiple calls to onMessageReceived, since the service might have been killed by the OS to free up memory.

I suggest storing your messages in a database. Whenever you receive a new message, insert it into the database, and delete it when the user reads it. Then you can easily query how many unread messages there are.