在使用手势识别器添加子视图时遇到用户界面故障

问题描述：

我正在开发一个应用程序，用户通过“卡片”进行滑动，这些卡片基本上是用API中的数据填充的UIViews。在使用手势识别器添加子视图时遇到用户界面故障

当应用第一次打开时，卡片被创建并作为子视图添加到超级视图。每次用户刷卡时，该卡都将从超级视图中移除。

当用户刷卡时，会在后台创建并缓存更多卡片。

当用户在最后一张卡片上时，我将缓存的卡片添加到当前正在显示的卡片背后的超级视图。

问题是，当卡被添加到超级视图时，我的手势识别器停止工作/毛刺（用户不能滑动）。几秒钟后，它再次开始工作，用户可以滑动。

如何阻止识别器发生故障？任何洞察力将不胜感激。

谢谢！

下面是一个创建/添加卡 //创建卡 FUNC createCards（新华美通：布尔）代码{

APICall.begin() { (info) in 

     DispatchQueue.main.async { 
      for i in info { 

       let frontView = frontView() 
       let backView = backView() 

       // Set up front and back views 
       self.viewSetup(view: frontView) 
       self.viewSetup(view: backView) 

       // Set up card view 
       let view = cardView(frame: frame) 
       view.addSubview(backView) 
       view.addSubview(frontView) 
       self.viewSetup(view: view) 
       view.isHidden = true 

       // function that add recognizer 
       self.dragging(view: view) 

       // cacheCard 
       if !firstCall{ 
        self.cache.add(cardView: view) 
       // add to view 
       }else{ 
        self.view.addSubview(view) 
       } 

      } 

      // Reveal current card 
      if firstCall { 
       self.view.subviews.last?.isHidden = false 
      } 

      print("DONE") 
     } 
    } 

}

继承人是添加识别代码/添加缓存

// dragging gesture helper 
func draggig(card: view){ 
    let gesture = UIPanGestureRecognizer(target: self, action: #selector(ViewController.wasDragged(_:))) 
    view.addGestureRecognizer(gesture) 
    view.isUserInteractionEnabled = true 

} 

// dragged gestrues 
func wasDragged(_ gesture: UIPanGestureRecognizer){ 

    // Only allow dragging when front is showing 
    if(showingFront){ 

     // Dragging code 
     let helper = draggingBeganHelper(gesture: gesture) 
     let card:UIView = helper[0] as! UIView 
     var rotation:CGAffineTransform = helper[1] as! CGAffineTransform 
     var stretch:CGAffineTransform = helper.last as! CGAffineTransform 

     if gesture.state == UIGestureRecognizerState.ended { 

      rotation = CGAffineTransform(rotationAngle: 0) 
      stretch = rotation.scaledBy(x: 1, y: 1) 

      //Remove card from superview 
      card.removeFromSuperview() 

      // Store cards in cache 
      if(self.view.subviews.count == lastCardIndex + cardOffset){ 

       createCards(false) 

      } 

      // When at the second to last card 
      else if self.view.subviews.count == lastCardIndex+1{ 
       if cardCacheArray.isEmpty { 
        createCards(true) 
       } 
       else{ 
        DispatchQueue.main.async { 
         for i in cardCacheArray{ 
          self.view.insertSubview(i, belowSubview: self.view.subviews[lastCardIndex]) 
         } 
         self.cache.empty() 
        } 
       } 
      } 
     } 
    } 

} 

func draggingBeganHelper(gesture: UIPanGestureRecognizer) -> [AnyObject]{ 
    // Card dragging gesture setup 
    let translation = gesture.translation(in: self.view) 
    let card = gesture.view 
    card?.center = CGPoint(x: (card?.center.x)! + translation.x, y: (card?.center.y)! + translation.y) 
    let xFromCenter = (card?.center.x)! - self.view.bounds.width/2 
    let scale = min(100/abs(xFromCenter),1) 
    let rotation = CGAffineTransform(rotationAngle: xFromCenter/200) 
    let stretch = rotation.scaledBy(x: scale, y: scale) 
    card?.transform = stretch 

    return [card!,rotation as AnyObject,stretch as AnyObject] 
}

因为事情工作（但最终）的方式，你可能意味着你已经编写了“基准线”的权利。如果您可以发布一些代码供我们查看，这将有所帮助。 – dfd

@dfd添加了代码 –

答

想通了。一次加载太多的UIViews。更好和更顺利的临近者将是不断回收两个UIViews

在使用手势识别器添加子视图时遇到用户界面故障

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