protected void onListItemClick(ListView l, View v, int position, long id) {
    super.onListItemClick(l, v, position, id);
     View element = this.getListAdapter().getView(position, null, null);
    if (clicked.contains(position)) {
        int i = clicked.indexOf(position);
        clicked.remove(i);
        element.setBackgroundColor(getResources().getColor(R.color.white));
    } else {
        clicked.add(position);
        element.setBackgroundColor(getResources().getColor(R.color.blue_1));
    }
}