Question

Let’s say that the user has invoked the 2nd activity from the main activity.
he/she did not do anything on the 2nd activity for a $period of time.
How to return to the main activity Pragmatically and not keeping the 2nd activity showing
I am using this for a kiosk application

Answer 1

Use a handler to post a runnable with a delay.

Handler h = new Handler();

Runnable r = new Runnable() {

    @Override
    public void run() {
        finish();
    }
};

private void resetTimeout()
{
    h.removeCallbacks(r);
    h.postDelayed(r, 10*60*1000); // delay 10 minutes
}

@Override
protected void onResume() {
    super.onResume();
    resetTimeout();
};