ios - Swift 3 委托(delegate)，协议(protocol)——TapGesture 不工作

Question

我不明白为什么我的点击手势不起作用。黑色取消窗口显示正常，但当我点击黑色窗口时，没有调用 handleCancel() 函数。

import UIKit

protocol BlackCancelWindowDelegate {
    func handleCancel()
}

class BlackCancelWindow: NSObject {
    let blackView = UIView()
    var delegate: BlackCancelWindowDelegate?
    var frame: CGRect?

    override init() {
        super.init()
    }

    func showCancelWindow() {
        if let window = UIApplication.shared.keyWindow {
            blackView.backgroundColor = UIColor(white: 0, alpha: 0.5)
            blackView.frame = frame ?? window.frame
            blackView.alpha = 0

            window.addSubview(blackView)
            let tapToDismiss = UITapGestureRecognizer(target: self, action: #selector(handleCancel))
            tapToDismiss.numberOfTapsRequired = 1
            blackView.addGestureRecognizer(tapToDismiss)


            UIView.animate(withDuration: 0.5,animations: {
                self.blackView.alpha = 1
            }, completion: nil)
        }
    }

    func handleCancel() {
        print("BlackCancelWindow cancel")
        UIView.animate(withDuration: 0.5, animations: {
            self.blackView.alpha = 0
        }, completion: nil)

        delegate?.handleCancel()
    }

}

class ViewController: UIViewController, BlackCancelWindowDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    @IBAction func showCancelWindow(_ sender: Any) {
        let cancelWindow = BlackCancelWindow()
        cancelWindow.delegate = self
        cancelWindow.showCancelWindow()
    }

    func handleCancel() {
        print("Delegate cancel")
    }
}

Answer 1

不确定为什么这行得通而我以前的代码行不通，但诀窍是子类化 UIView 而不是 NSObject。像这样...

import UIKit

protocol BlackCancelViewDelegate {
    func handleCancel()
}

class BlackCancelView: UIView {
    var delegate: BlackCancelViewDelegate?

    override init(frame: CGRect) {
        super.init(frame: frame)

        backgroundColor = UIColor(white: 0, alpha: 0.5)
    }

    convenience init() {
        if let window = UIApplication.shared.keyWindow {
            self.init(frame: window.frame)
        } else {
            self.init()
        }
    }

    func showCancelWindow() {
        if let window = UIApplication.shared.keyWindow {
            alpha = 0

            window.addSubview(self)
            let tapToDismiss = UITapGestureRecognizer(target: self, action: #selector(handleCancel))
            addGestureRecognizer(tapToDismiss)

            UIView.animate(withDuration: 0.5,animations: {
                self.alpha = 1
            }, completion: nil)
        }
    }

    func handleCancel() {
        print("BlackCancelView cancel")

        UIView.animate(withDuration: 0.5,animations: {
            self.alpha = 0
        }, completion: nil)

        delegate?.handleCancel()
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

class ViewController: UIViewController, BlackCancelViewDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    @IBAction func showCancelWindow(_ sender: Any) {
        let cancel = BlackCancelView()
        cancel.delegate = self
        cancel.showCancelWindow()
    }

    func handleCancel() {
        print("Delegate cancel")
    }
}

我不确定我是否以正确的方式执行了这些初始化函数。如果有更好的方法，请告诉我。