code: public final void setCheckedStateBackgroundColor(@ColorInt int backgroundColor) {
          if ((backgroundColor != mCheckedBackgroundColor) &&
              (null != mCheckedBackgroundPaint)) {
              mCheckedBackgroundPaint.setColor(backgroundColor);
              if (isChecked()) {
                  invalidate();
              }
          }
  
          mCheckedBackgroundColor = backgroundColor;
      }
docs: Sets the check state background color.
  
  @param backgroundColor