public void changeBackground() {
			if (eventCheck) {
				setBackgroundResource(R.drawable.background_checkbox);
				LayerDrawable layer = (LayerDrawable) getBackground();
				GradientDrawable shape = (GradientDrawable) layer
						.findDrawableByLayerId(R.id.shape_bacground);
				shape.setColor(backgroundColor);
			} else {
				setBackgroundResource(R.drawable.background_switch_ball_uncheck);
			}
		}
Make a dark color to press effect

@return
MaterialDesignLibrary/MaterialDesign/src/main/java/com/gc/materialdesign/views/Switch.java