Auto Scroll a Android ViewGroup top to bottom and bottom to top

Question

Here I'm trying to scroll a GridView automatically top to bottom and as it comes to last item scroll it back to top from bottom using smoothScrollToPosition but its very fast. The code is :

  homeGridView.postDelayed(new Runnable() {
        public void run() {
            //       ObjectAnimator.ofInt(homeGridView, "scrollY",  homeGridView.getCount()-1).setDuration(1000).start();
            homeGridView.smoothScrollToPosition(homeGridView.getCount() - 1);
            homeGridView.postDelayed(new Runnable() {
                public void run() {
                    // ObjectAnimator.ofInt(homeGridView, "scrollY",  0).setDuration(1000).start();
                    homeGridView.smoothScrollToPosition(0);
                }
            }, 1000);
        }
    }, 1000);

Now I just want to know that how can I decrease speed of this scroll or something better this.