The message is even clearer than NullPointerException messages given by Java
: It clearly says that rLayout is null.
And your code assigns the result of the findViewById method to rLayout, so clearly that result is null. So you should
look into why app.findViewById() is returning null. Without knowing anything about your application I would guess that the method is looking up views based on an ID, and the ID you passed to the method doesn't have any corresponding view.