code: public void addOpacityBar(OpacityBar bar) {
  		mOpacityBar = bar;
  		// Give an instance of the color picker to the Opacity bar.
  		mOpacityBar.setColorPicker(this);
  		mOpacityBar.setColor(mColor);
  	}
docs: Add a Opacity bar to the color wheel.
  
  @param bar The instance of the Opacity bar.