Swift利用Runtime防止按钮重复点击

OC中通过Runtime防止按钮简直就是轻而易举的事情,在分类中使用load方法,进行方法交换就行了.
但是这个事放在Swift中就不是那么友好了,特别是在Swift3.0中相继封掉了load方法与initialize方法后.

所幸,还是有大神给出了思路,在AppDelegate didFinishLaunchingWithOptions方法中进行方法交换
如下代码就是利用Runtime防止按钮重复点击.

// MARK: - 按钮的反复点击问题 交换方法
extension UIButton {
    
    
    /// 对外交换方法的方法 AppDelegate Launch中使用
    public  static func methodExchange() {
        DispatchQueue.once(token: "UIButton") {
            let originalSelector = Selector.sysFunc
            let swizzledSelector = Selector.myFunc
            changeMethod(originalSelector, swizzledSelector, self)
        }
    }
    
    
    /// Runtime方法交换
    ///
    /// - Parameters:
    ///   - original: 原方法
    ///   - swizzled: 交换方法
    ///   - object: 对象
    private static func changeMethod(_ original: Selector, _ swizzled: Selector, _ object: AnyClass) -> () {
        
        guard let originalMethod = class_getInstanceMethod(object, original),
              let swizzledMethod = class_getInstanceMethod(object, swizzled) else {
            return
        }
        
        let didAddMethod = class_addMethod(object, original, method_getImplementation(swizzledMethod), method_getTypeEncoding(swizzledMethod))
        if didAddMethod {
            class_replaceMethod(object, swizzled, method_getImplementation(originalMethod), method_getTypeEncoding(originalMethod))
        } else {
            method_exchangeImplementations(originalMethod, swizzledMethod)
        }
    }
    
    
    /// 结构体静态key
    private struct UIButtonKey {
        static var isEventUnavailableKey = "isEventUnavailableKey"
        static var eventIntervalKey = "eventIntervalKey"
    }
    
    /// 触发事件的间隔
    var eventInterval: TimeInterval {
        get {
            return (objc_getAssociatedObject(self, &UIButtonKey.eventIntervalKey) as? TimeInterval) ?? 0
        }
        set {
            objc_setAssociatedObject(self, &UIButtonKey.eventIntervalKey, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
        }
    }
    
    /// 是否可以触发事件
    fileprivate var isEventUnavailable: Bool {
        get {
            return (objc_getAssociatedObject(self, &UIButtonKey.isEventUnavailableKey) as? Bool) ?? false
        }
        set {
            objc_setAssociatedObject(self, &UIButtonKey.isEventUnavailableKey, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
        }
    }
    
    /// 手写的set方法
    ///
    /// - Parameter isEventUnavailable: 事件是否可用
    @objc private func setIsEventUnavailable(_ isEventUnavailable: Bool) {
        self.isEventUnavailable = isEventUnavailable
    }
    
    /// mySendAction
    @objc fileprivate func mySendAction(_ action: Selector, to target: Any?, for event: UIEvent?) {
        print("交换了按钮事件的方法")
        
        if isEventUnavailable == false {
            isEventUnavailable = true
            mySendAction(action, to: target, for: event)
            perform(#selector(setIsEventUnavailable(_: )), with: false, afterDelay: eventInterval)
        }
    }
}

fileprivate extension Selector {
    static let sysFunc = #selector(UIButton.sendAction(_:to:for:))
    static let myFunc = #selector(UIButton.mySendAction(_:to:for:))
}  

extension DispatchQueue {
    private static var onceTracker = [String]()
    
    open class func once(token: String, block:() -> ()) {
        //注意defer作用域，调用顺序——即一个作用域结束，该作用域中的defer语句自下而上调用。
        objc_sync_enter(self)
        defer {
            print("线程锁退出")
            objc_sync_exit(self)
        }
        
        if onceTracker.contains(token) {
            return
        }
        onceTracker.append(token)
        block()
        defer {
            print("block执行完毕")
        }
    }
}

方法交换使用如下

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        UIButton.methodExchange()
        return true
    }

在button使用如下

let button = UIButton(frame: CGRect(x: 0, y: 300, width: 100, height: 22))
button.setTitle("按钮", for: .normal)
button.setTitleColor(.black, for: .normal)
button.eventInterval = 2.0  //  按的时间间隔, 设置为0的时候就是可以反复点击
view.addSubview(button)