private void placeBall() {
		ViewHelper.setX(ball, getHeight() / 2 - ball.getWidth() / 2);
		ball.xIni = ViewHelper.getX(ball);
		ball.xFin = getWidth() - getHeight() / 2 - ball.getWidth() / 2;
		ball.xCen = getWidth() / 2 - ball.getWidth() / 2;
		placedBall = true;
		ball.animateCheck();
	}
Make a dark color to press effect

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