String ns = Context.NOTIFICATION_SERVICE;
NotificationManager mNotificationManager = (NotificationManager) this.getSystemService(ns);
int icon =
Android only displays one expanded notification by default. Your notification doesn't lose its content, it just gets compressed and only shows the normal one-line content. But it seems that you don't specify this, therefore the compressed notification is empty.
You may use setContentTitle() and setContentText() to set the one-line texts.