Finish parent and current activity in Android

Question

I have 3 activities. Activity A which leads to activity B, which in turn can go back to activity A or start activity C. However, if I press back in activity C the app should

Answer 1

From the screen(B) you want to start the screen(C) with NO back screen, just start this screen (C) with:

screenC.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP 
    | Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_SINGLE_TOP);
startActivity(screenC);
finish();

The back in screenC will exit the application.