Android : Notification listener service for WhatsApp

I'm using the last Kikat API to acess to the user notification and get some data. Currently I use this code:

@Override
public void onNotificationPosted(StatusBarNotification arg0) {
    String originator = arg0.getPackageName();
    Bundle extras = arg0.getNotification().extras;
    if (extras != null) {
        String title = extras.getString(Notification.EXTRA_TITLE);
        String subText = extras.getString(Notification.EXTRA_SUB_TEXT);
        String text = extras.getString(Notification.EXTRA_TEXT);
        CharSequence ticker = arg0.getNotification().tickerText;
        //do something
    }
}

This code doesn't work with multiple messages of WhatsApp. Unfortunately I don't use this app so I don't know what fields uses. Can someone give me some information? Can someone share a dumpsys notificationADB command output?