code: public final void setPreviewBackground(final Drawable background) {
          this.previewBackground = background;
  
          if (previewLoader != null) {
              previewLoader.setBackground(background);
          }
  
          adaptPreviewView();
      }
docs: Sets the background of the preview of the preference's color.
  
  @param background
  The background, which should be set, as an instance of the class {@link Drawable} or
  null, if no background should be shown