I try to develop small music app which has 3 screens, so want to provide go/back UI between them.

My plan is using BACK button on device to back to previous screen, but BACK button kills "Activity". (see  http://forum.processing.org/topic/sketches-don-t-want-to-quit-on-the-phone)

It seems nice to have different Activity for each 3 screens. So I tested duplicating PApplet for each screens and it works fine. But it means resources for PApplet is also duplicated. I'm happy if I can replace base PApplet Activity and new Activity instance.

Any suggestion or another good way?