In Scrollable ListView , getChildAt().setBackgroundColor() after listView.setSelection()

Question

i have created a Fragment, in which i am populating the scrollable ListView using SimpleAdpater. I am scrolling down to a item in ListView using
listView.setSelection(location_of_time_in_list);
After that i am calling a function
setListviewSelection(listView, location_of_time_in_list);
to change background color of the selected item(selected by setSelection())

sa = new SimpleAdapter(getActivity(), arraylist, R.layout.train_column,new String[] {"location", "time", "direction", "speed"}, new int[] {R.id.TRAIN_CELL, R.id.TIME_CELL, R.id.DIRECTION_CELL, R.id.SPEED_CELL});
                listView.setAdapter(sa);
                listView.setSelection(location_of_time_in_list);
                setListviewSelection(listView, location_of_time_in_list);

 public static void setListviewSelection(final ListView list, final int pos) {
    list.postDelayed(new Runnable() {
        @Override
        public void run() {
            View v = list.getChildAt(pos);
            if (v != null) {
                v.setBackgroundColor(Color.CYAN);
            }
        }
    },100);

But the background Color is not changing. Please Help??