Android how to show notification on screen

I've been working on push notifications and I am able to implement it and display it on status bar, the problem I am facing is that I want to display it even if the phone is lock, Under the lock screen where it says ("drag to unlock"), I have seen notifications like that but cant find any example to that.

Example: Just like when you received a missed call , it will show it under the lock button on your screen.

Code:

String ns = Context.NOTIFICATION_SERVICE;

NotificationManager mNotificationManager = (NotificationManager) getSystemService(ns);

int icon = R.drawable.icon_launcher;

CharSequence tickerText = "MyApplication";

long when = System.currentTimeMillis();

Notification notification = new Notification(icon, tickerText, when);

notification.defaults |= Notification.DEFAULT_SOUND|Notification.DEFAULT_VIBRATE|Notification.DEFAULT_LIGHTS;;

CharSequence contentTitle = this.title;

CharSequence contentText = this.message;

Intent notificationIntent = new Intent(this, MainActivity.class);

PendingIntent contentIntent = PendingIntent.getActivity(this, 0, notificationIntent, 0);

notification.setLatestEventInfo(context, contentTitle, contentText, contentIntent);

mNotificationManager.notify(NOTICE_ID, notification);

Source: Tips4all, CCNA FINAL EXAM