How to control activity stack/clear activity stack in Android

Question

I have an application that goes as follows (Home being the launch activity):

D
C
B
A
Home

My flow goes as follows:

The user starts activity A from Home , which flows to B and C . When the user leaves activity C , I want A , B , and C to be destroyed. That is, if the user presses BACK in activity D , it goes back to Home .

The user must be able to control program flow normally through activity A , B , and C . So if they press the back button in activity C , it goes back to activity B .

I've looked at Intent flags such as CLEAR_TOP and NEW_TASK , but none of them seem to do what I want them to.

I'd appreciate any help!

Answer 1

Perhaps you are looking for FLAG_ACTIVITY_TASK_ON_HOME ? It requires API level 11 though:(

for API level <11, this can be done:

when starting activity B and C, use startActivityForResult(). When starting activity D, do this:

startActivity(D);
setResult(KILL_YOURSELF); //KILL_YOURSELF is some arbitrary int that you use to identify that the other activities should exit
finish(); //finish the activity

This will kill activity C. Then in activity A and B, override onActivityResult like this:

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if(resultCode == KILL_YOURSELF) {
            setResult(KILL_YOURSELF);
            finish();
        }
    }

Thus activity B will finish, which in turn will trigger onActivityResult in A, so it will also finish.

Answer 2

Simply intercept the Back Button in Activity D, and upon intercepting the Back Button, head over to the Home Activity. You may / maynot want to finish 'D' activity as you are heading over to the Home Activity.