EZbutton help you to answer (normal / speaker phone) / be silent / reject by volume and camera buttons.
It may not work on some phones. You can cancel the order within 15 mins if it doesn't work. (By Google policy)
(You can set actions by yourself and can use your default incoming call screen as well at the same time.)
This app use signal from default phone app, So please think it as an app helping answering a call.
* EZanswer includes all the following apps.
1. EZtouch : asnwer / reject a call by screen touch.
2. EZbutton : answer / reject a call by hardware button.
3. EZshake : answer / reject a call by shake and upside down.
4. EZblock : call blocker.
5. EZnotice : Notice hang up by vibration.
6. Full screen Image (caller ID)
7. Display additional info (Company, department, title, notes)