Is it reasonable to have a "back" button in an Android app?

Question

Please give me feed back whether it's good practice to have a back button in activity, or is it just nonsense? Maybe some android phones don't have back/return key? Or do all models have them?

Answer 1

All android phones will have the back key. Putting a back button is, IMO, ugly and unnecessary; you better use your space with useful stuff. Sometimes your boss will just obligate you to put a Back button, usually because (sadly) most of the android sketchs are based on iPhone's ones... so the only reason why I'd put a back button is to not get fired (well, sometimes it's much better getting fired than becoming a poor programmer).

Answer 2

Piling on. I recently had a debate about this where we talked about design metaphors for android, iPhone, and windows mobile. The bottom line where we agreed is that you should follow the design metaphors for the device you are developing on. For android, the design should not include a back button because users are used to the physical back button. If one is required, the physical button should work as well.