Swift 中的 UIScrollView 子类用于触摸开始和触摸移动

Question

我正在使用 Swift 1.2

我正在尝试在已接受答案的第二条评论中使用此 UIScrollview touchesbegan,touchesmoved,touchesended actions 和 link。

我正在使用具有自动布局的故事板，我在自定义 Class 中为 UIScrollView 设置了自定义 class。

我在包含自定义 UIScrollView

的 UIViewController 中没有收到任何这些触摸事件

编辑：使用@Victor Sigler 的回答更新了我的代码。

自定义滚动视图代码：

import UIKit

protocol PassTouchesScrollViewDelegate {

func scrollTouchBegan(touches: Set<NSObject>, withEvent event: UIEvent)
func scrollTouchMoved(touches: Set<NSObject>, withEvent event: UIEvent)
}

class PassTouchesScrollView: UIScrollView {

var delegatePass : PassTouchesScrollViewDelegate?

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

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

override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {

    self.delegatePass?.scrollTouchBegan(touches, withEvent: event)


}

override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {

    self.delegatePass?.scrollTouchMoved(touches, withEvent: event)

}

}

我的ViewController：

import UIKit

class ViewController: UIViewController, PassTouchesScrollViewDelegate {

@IBOutlet weak var scrollView: UIScrollView!

override func viewDidLoad() {
    super.viewDidLoad()

    scrollView.delegatePass = self
}

func scrollTouchBegan(touches: Set<NSObject>, withEvent event: UIEvent)    {

    println("began \(touches)")

}

func scrollTouchMoved(touches: Set<NSObject>, withEvent event: UIEvent)      {

    println("moved \(touches)")
}     

}

我试图让用户在 UIImage 上画一条线，我使用 PanGesture Recognizer 开始工作，但性能很差，尤其是在较旧的硬件上，我遵循了 Ray Wenderlich 教程，该教程使用 touches Began并且性能要好得多，但是它是在 UIView 而不是 ScrollView 上。我需要一个 UIScrollView，因为在用户绘制图像之前，他们可以放大图像并围绕它放大。

Answer 1

touchesBegan 仅适用于 UIView 的子类。把它从你的 UIViewController 中拿出来让它工作。

UIResponder Apple Docs

Answer 2

你想错了。如果您想知道 UIScrollView 何时移动，则无需 subclass 它。 iOS 已经在 UIScrollViewDelegate.

中设置了你需要的所有方法

您必须实现 UISCrollViewDelegate 才能收到有关 UIScrollView 中的操作的通知，并通过 Interface Builder 或在代码中设置 delegate，由您决定。

请参阅以下示例以了解如何执行此操作：

class ViewController: UIViewController, UIScrollViewDelegate {

     @IBOutlet weak var scrollView: UIScrollView!

     override func viewDidLoad() {
       super.viewDidLoad()
       self.scrollView.delegate = self
     }
}

不过，如果您想知道它是如何按照您上面解释的方式进行操作的，则必须按照以下步骤操作：

您必须像在 class PassTouchesScrollView 中那样从 UIScrollView class 中继承 class 并实施委托模式通过以下方式收到关于 UIScrollView 的通知：

import UIKit

protocol PassTouchesScrollViewDelegate {
   func touchBegan()
   func touchMoved()
}


class PassTouchesScrollView: UIScrollView {

  var delegatePass : PassTouchesScrollViewDelegate?

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

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

  override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {

     // Notify it's delegate about touched
     self.delegatePass?.touchBegan()

    if self.dragging == true {
       self.nextResponder()?.touchesBegan(touches, withEvent: event)
    } else {
       super.touchesBegan(touches, withEvent: event)
    }

 }

  override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent)  {

     // Notify it's delegate about touched
     self.delegatePass?.touchMoved()

     if self.dragging == true {            
        self.nextResponder()?.touchesMoved(touches, withEvent: event)
     } else {            
       super.touchesMoved(touches, withEvent: event)
     }
  }   
}

你的classViewController必须按以下方式实现：

class ViewController: UIViewController, UIScrollViewDelegate {

  @IBOutlet weak var scrollView: PassTouchesScrollView!

  override func viewDidLoad() {
    super.viewDidLoad()        
    scrollView.delegate = self  
    scrollView.delegatePass = self      
  }

  override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
  }

  func touchMoved() {
     println("touch moved")
  }

  func touchBegan() {
     println("touch began")
  }

}

您必须在界面生成器中 select 您的 UIScrollView 并将 class 设置为您的 class PassTouchesScrollView , 在 class 部分的 Identity Inspector 中。

您应该会在控制台中看到以下内容：

touch began
touch began
touch began
touch began
touch began
touch began
touch moved
touch move

希望对你有所帮助。

Answer 3

试试这个

  extension UIScrollView {

    override open func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        self.next?.touchesBegan(touches, with: event)
        print("touchesBegan")
    }

    override open func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
        self.next?.touchesMoved(touches, with: event)
        print("touchesMoved")
    }

    override open func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        self.next?.touchesEnded(touches, with: event)
        print("touchesEnded")
    }

}

Swift 中的 UIScrollView 子类用于触摸开始和触摸移动

Subclass UIScrollView in Swift for touches Began & touches Moved

uiscrollview

touchesbegan

swift