UITapGestureRecognizer 在自定义 UIView 中不起作用

Question

我的 ViewController 如下所示。在这里，我调用我的自定义视图并以编程方式设置它。我面临的问题是点击手势不起作用。即使它没有被调用。

这个 [https://stackoverflow.com/questions/60931438/uitapgesturerecognizer-not-working-with-custom-view-class][1] 也与此类似，但我无法理解我的案子。我被困在这里好几个小时了。

class myViewController : ViewController {
    
    init() {
        super.init(nibName: nil, bundle: nil)
        
        self.view.addSubview(self.myView)
        
        self.myView.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive = true
        self.myView.centerYAnchor.constraint(equalTo: self.view.centerYAnchor).isActive = true
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    lazy var myView : MyCustomView = {
        let view = MyCustomView(frame: CGRect(x: 0, y: 0, width: 476.0, height: 398.0))
        view.translatesAutoresizingMaskIntoConstraints = false
        return view
    }()
}

我的自定义视图是这样的。

class MyCustomView : UIView {
  
    override init(frame: CGRect) {
        super.init(frame: frame)
             
        self.widthAnchor.constraint(equalToConstant: frame.width).isActive = true
        self.heightAnchor.constraint(equalToConstant: frame.height).isActive = true

        self.mView.topAnchor.constraint(equalTo: self.topAnchor, constant: 10).isActive = true
        self.mView.trailingAnchor.constraint(equalTo: self.trailingAnchor, constant: -20).isActive = true
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    private lazy var mView: UIView = {
        let view = UIView()
        view.translatesAutoresizingMaskIntoConstraints = false
        view.backgroundColor = UIColor.init(hexString: "#EDEEEF")
        view.isUserInteractionEnabled = true
        
        let gesture = UITapGestureRecognizer(target: self, action:  #selector(tappedDropDown))
        view.addGestureRecognizer(gesture)
        
        return view
    }() 

    @objc func tappedDropDown(sender : UITapGestureRecognizer){
        print("Tapped")
    }
}

Answer 1

示例代码有很多问题会停止工作，有些甚至会停止编译（未终止的字符串文字、尝试设置自动布局 (AL) 约束而不将 TAMIC 设置为 false 等）。

但我认为*停止点击手势工作的问题是布局代码是帧大小和 AL 约束的混合，它没有按照您认为的方式布局，这意味着自定义视图的子视图视图也没有收到响应手势。

更改布局代码以使其全部为 AL，使轻按手势工作，而无需对手势识别器或其操作方法进行任何更改。

我假设您的目标布局是带有子视图（您的 CustomView）的 VC 视图，该子视图又具有自己的子视图（您的 mView，下面我已将其重命名为 subView它更清晰），在三层金字塔类型的堆栈中。

我在上面说“思考”是因为我可能在修复布局代码时纠正了一些其他错误。我只更正了编译并提供工作 UI 所需的代码。我没有故意解决任何其他问题，因为它们与问题无关。

下面的代码展示了三个视图（VC 的视图、myView（CustomView）和 CustomView 的subview，并将tapGestureRecogniser 添加到subView。手势识别器点击时触发其选择器方法。它可能不会按照您想要的方式布置，因为很难说出您尝试实现的布局，但它确实证明了gestureRecogniser按预期工作。

class myViewController : UIViewController {
   
   lazy var myView : MyCustomView = {MyCustomView(frame: .zero)}()
   
   init() {
      super.init(nibName: nil, bundle: nil)
      view.heightAnchor.constraint(equalToConstant: 600).isActive = true
      
      view.addSubview(myView)
      myView.topAnchor.constraint(equalTo: view.topAnchor, constant: 50).isActive = true
      myView.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -50).isActive = true
      myView.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -50).isActive = true
      myView.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 50).isActive = true

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

class MyCustomView : UIView {
   override init(frame: CGRect) {
      super.init(frame: frame)
      backgroundColor = .systemOrange
      translatesAutoresizingMaskIntoConstraints = false
      addSubview(subView)
      subView.leadingAnchor.constraint(equalTo: leadingAnchor, constant: -50).isActive = true
      subView.trailingAnchor.constraint(equalTo: trailingAnchor, constant: -50).isActive = true
      subView.topAnchor.constraint(equalTo: topAnchor, constant: 50).isActive = true
      subView.bottomAnchor.constraint(equalTo: self.bottomAnchor, constant: -50).isActive = true
   }
   
   required init?(coder aDecoder: NSCoder) {
      fatalError("init(coder:) has not been implemented")
   }
   
   private lazy var subView: UIView = {
      let view = UIView()
      view.backgroundColor = .systemBlue
      view.translatesAutoresizingMaskIntoConstraints = false
      view.isUserInteractionEnabled = true
      
      let gesture = UITapGestureRecognizer(target: self, action:  #selector(tappedDropDown))
      view.addGestureRecognizer(gesture)
      return view
   }()
   
   @objc func tappedDropDown(sender : UITapGestureRecognizer){
      print("Tapped")
   }
}

Answer 2

我认为问题在于你的函数 tu 在 ViewController 之外运行。只需执行以下操作：

class myViewController : ViewController {

    @objc func tappedDropDown(sender : UITapGestureRecognizer){
        print("Tapped")
    }

    init() {
        super.init(nibName: nil, bundle: nil)
    
        self.view.addSubview(self.myView)
    
        self.myView.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive = true
        self.myView.centerYAnchor.constraint(equalTo: self.view.centerYAnchor).isActive = true
    }

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

    lazy var myView : MyCustomView = {
        let view = MyCustomView(frame: CGRect(x: 0, y: 0, width: 476.0, height: 398.0))
        view.translatesAutoresizingMaskIntoConstraints = false

        let gesture = UITapGestureRecognizer(target: self, action:  #selector(tappedDropDown))
        view.addGestureRecognizer(gesture)

        return view
    }()
}

并且，从您的自定义类中删除我在此处添加的行。