How to reply to a notification using NotificationListener Service in android

Question

I am working on an android app where I need to get incoming message from whatsapp or any other chatting app and then reply to that message using my app.

I am able to extract message and other data from notification using NotificationListener Service, but I don't know how to reply to that notification from my app.

I got all the information using the following method of NotificationListener Class.

 @Override
public void onNotificationPosted(StatusBarNotification sbn) {
    super.onNotificationPosted(sbn);

    Intent intent = new Intent(this, ChatHeadService.class);
    startService(intent);
    bindService(intent, mConnection, Context.BIND_AUTO_CREATE);

    String key = sbn.getKey();    // notification key
    PendingIntent intent1 = sbn.getNotification().contentIntent;  // pending intent
    String pack = sbn.getPackageName();     // package name of app
    Bundle noti = sbn.getNotification().extras;      // extra bundle of notification
    String name = noti.getString("android.title");   // name of the sender
    Bitmap img = sbn.getNotification().largeIcon;   // the icon of the sender user
    CharSequence[] textlines = noti.getCharSequenceArray("android.textLines");
    if (textlines != null)
        Log.i("textlines", textlines.toString());

Now I need to reply to the above notification!