How to clear previous activity stack and Exit Application on back button?

Question

I have three activities:

A,B,C

A is home screen.

Activities are launched as follow A->B->C

If I come to home screen using backbutton, I want to clear activity stack/previous activities history and it should exit the application.

Can anyone guide me how to achieve this?

Answer 1

Very simple: use intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); on an intent used to start the activity A.

Answer 2

You can do following:
1. Set clearTaskOnLaunch = "true" in AndroidManifest, in declaration of activity A
2. In activity C:

@Override
public void onBackPressed(){
    moveTaskToBack(true);
}

So if user presses back - it comes back to homescreen.
If user launches application again - task stack clears and he comes to root activity (A)