code: public static StateListDrawable getSelectableImageButtonBackground(int selected_color) {
  		ColorDrawable selectedColor = new ColorDrawable(selected_color);
  		StateListDrawable states = new StateListDrawable();
  		states.addState(new int[]{android.R.attr.state_pressed}, selectedColor);
  		states.addState(new int[]{android.R.attr.state_activated}, selectedColor);
  		return states;
  	}
docs: helper method to generate the ImageButton background with specified highlight color.
  
  @param selected_color the color shown as highlight
  @return