【Swift 2.1】为 UIView 添加点击事件和点击效果

extension UIView {

    func addOnClickListener(target: AnyObject, action: Selector) {
        let gr = UITapGestureRecognizer(target: target, action: action)
        gr.numberOfTapsRequired = 1
        userInteractionEnabled = true
        addGestureRecognizer(gr)
    }

}

class UIViewEffect : UIView {

    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
        backgroundColor = UIColor.groupTableViewBackgroundColor()
    }

    override func touchesCancelled(touches: Set<UITouch>?, withEvent event: UIEvent?) {
        UIView.animateWithDuration(0.15, animations: { () -> Void in
            self.backgroundColor = UIColor.clearColor()
        })
    }

    override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
        UIView.animateWithDuration(0.15, animations: { () -> Void in
            self.backgroundColor = UIColor.clearColor()
        })
    }
}