swift面向协议编程（1）

声明一个Shake动画的协议

protocol Shakeable {
}

给协议拓展一个shake的方法

extension Shakeable where Self: UIView {
    
    func shake() {
        
        
        let animation = CABasicAnimation(keyPath: "position")
        animation.duration = 0.05
        animation.repeatCount = 5
        animation.autoreverses = true
        animation.fromValue = NSValue(cgPoint: CGPoint(x: center.x - 4, y: center.y - 4))
        animation.toValue = NSValue(cgPoint: CGPoint(x: center.x + 4, y: center.y + 4))
        layer.add(animation, forKey: "position")
        
        
    }
}

写一个自定一个button 遵循协议

class ActionButton: UIButton,Shakeable {
}

之后创建ActionButton 就拥有了shake事件 ，如果其他控件也需要用到这个shake 只需要遵循shakeable协议即可