code: public void setFooterDivider(Drawable drawable) {
          mFooterDivider = drawable;
          if (drawable != null) {
              mFooterDividerHeight = drawable.getIntrinsicHeight();
          } else {
              mFooterDividerHeight = 0;
          }
          mContentView.setWillNotDraw(drawable == null);
          mContentView.invalidate();
      }
docs: Set footer divider.
  
  @param drawable