Question

I have four activities a,b,c,d. Activity a is the main activity which then calls b,c and d which then does some computation. I know I can prevent the activity from building up in my application by android:noHistory="true" attribute in those activites . But the issue is if I am in activity c,when I press the back button I want to go to b, but if d finishes I want b and c to be removed and only a to displayed. Is there any way to achieve this?

Answer 1

Put this code in each of your activities, changing it slightly each time. That way you override the back button’s normal function

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event)  {
        if (keyCode == KeyEvent.KEYCODE_BACK
                && event.getRepeatCount() == 0) {
            //start the desired activity
        }

        return super.onKeyDown(keyCode, event);
    }

Also, if you are only supporting android 2.0+ then you can use this

@Override
public void onBackPressed() {
    // start your desired activity here
    return;
}

Just put either of these in each of your activities, then start the correct activity

To close one specific activity, look at this page – How to clear specific activity from the stack history?