code: public void setDefaultIndicatorColor(int selectedColor,int unselectedColor){
          if(mUserSetSelectedIndicatorResId == 0){
              mSelectedGradientDrawable.setColor(selectedColor);
          }
          if(mUserSetUnSelectedIndicatorResId == 0){
              mUnSelectedGradientDrawable.setColor(unselectedColor);
          }
          resetDrawable();
      }
docs: if you are using the default indicator , this method will help you to set the selected status and
  the unselected status color.
  @param selectedColor
  @param unselectedColor