单击 UIBarButton 显示 toast 和双击返回操作需要执行答案

【问题标题】：on single tap UIBarButton display toast and on double tap back action need to perform单击 UIBarButton 显示 toast 和双击返回操作需要执行
【发布时间】：2018-04-03 10:28:10
【问题描述】：

我在导航栏中有一个 UIBarButton，点击后退按钮（第一次点击）我需要显示 toast（如警告），双击我需要快速退出页面，

以下用于显示 toast 的代码，其工作正常，

let toastLabel = UILabel(frame: CGRect(x: 20, y: self.view.frame.size.height-100, width: 350, height: 35))
    toastLabel.backgroundColor = UIColor.black.withAlphaComponent(0.6)
    toastLabel.textColor = UIColor.white
    toastLabel.textAlignment = .center;
    toastLabel.font = UIFont(name: "Montserrat-Light", size: 12.0)
    toastLabel.text = "demo"
    toastLabel.alpha = 1.0
    toastLabel.layer.cornerRadius = 10;
    toastLabel.clipsToBounds  =  true
    self.view.addSubview(toastLabel)
    UIView.animate(withDuration: 2.0, delay: 0.1, options: .curveEaseOut, animations: {
        toastLabel.alpha = 0.0
    }, completion: {(isCompleted) in
        toastLabel.removeFromSuperview()
    })

请指导我完成这项任务。

【问题讨论】：

标签： ios swift3 navigationbar

【解决方案1】：

在 UIButton 上为控件事件 UIControlEventTouchDownRepeat 添加一个 target-action，并且仅当触摸的 tapCount 为 2 时才执行操作。如下面的 Swift 3 中

button.addTarget(self, action: #selector(multipleTap(_:event:)), for: UIControlEvents.touchDownRepeat)

然后添加如下选择器

func multipleTap(_ sender: UIButton, event: UIEvent) {
    let touch: UITouch = event.allTouches!.first!
    if (touch.tapCount == 2) {
        // do action.
    }
}

【讨论】：

【解决方案2】：

override func viewDidLoad() {
        super.viewDidLoad()

        self.navigationItem.hidesBackButton = true
        let button = UIButton(type: .system)
        button.frame = CGRect(x: 0, y: 0, width: 80, height: 40)
        button.setTitle("Back", for: .normal)

        //Gesture Recognizer
        let singleTap = UITapGestureRecognizer(target: self, action: #selector(handleSingleTap))
        singleTap.numberOfTapsRequired = 1
        let doubleTap = UITapGestureRecognizer(target: self, action: #selector(handleDoubleTap))
        doubleTap.numberOfTapsRequired = 2
        button.addGestureRecognizer(singleTap)
        button.addGestureRecognizer(doubleTap)
        singleTap.require(toFail: doubleTap)

        let barButton = UIBarButtonItem(customView: button)
        self.navigationItem.leftBarButtonItem = barButton
    }
    @objc func handleSingleTap(sender: UITapGestureRecognizer? = nil) {
        let toastLabel = UILabel(frame: CGRect(x: 20, y: self.view.frame.size.height-100, width: 350, height: 35))
        toastLabel.backgroundColor = UIColor.black.withAlphaComponent(0.6)
        toastLabel.textColor = UIColor.white
        toastLabel.textAlignment = .center;
        toastLabel.font = UIFont(name: "Montserrat-Light", size: 12.0)
        toastLabel.text = "demo"
        toastLabel.alpha = 1.0
        toastLabel.layer.cornerRadius = 10;
        toastLabel.clipsToBounds  =  true
        self.view.addSubview(toastLabel)
        UIView.animate(withDuration: 2.0, delay: 0.1, options: .curveEaseOut, animations: {
            toastLabel.alpha = 0.0
        }, completion: {(isCompleted) in
            toastLabel.removeFromSuperview()
        })
        print("Single Tap detected")
    }
    @objc func handleDoubleTap(sender: UITapGestureRecognizer? = nil) {
        print("Double Tap detected")
    }

【讨论】：

【解决方案3】：

使用UIControlEventTouchDownRepeat 事件，当tapCount 为2 时执行操作。

【讨论】：