UIPanGestureRecogniser工作不正常

Question

我有了這個函數來處理視圖的拖動：+

func handlePan(recognizer:UIPanGestureRecognizer) { 
    let translation = recognizer.translationInView(self.view) 



    let newCenter = CGPointMake(self.view.bounds.size.width/2, 
     recognizer.view!.center.y + translation.y) 

    print("the translation x:\(translation.x) & y:\(newCenter.y)") 

    if (newCenter.y >= 397 && newCenter.y <= 632) { 
     recognizer.view!.center = newCenter 


     recognizer.setTranslation(CGPointZero, inView: self.view) 
    } 


} 

的立場是正確的。 但是，當我拖動時需要移動的視圖經常會阻止，所以我需要停下來並開始再次拖動它。

我該如何解決這個問題？

編輯：我的代碼看起來現在這個樣子，但我仍然有問題：

func handlePan(recognizer:UIPanGestureRecognizer) { 
    let translation = recognizer.translationInView(self.view) 


     switch recognizer.state { 
      case .Ended:fallthrough 
      case .Changed: 

       let newCenter = CGPointMake(self.view.bounds.size.width/2, 
        recognizer.view!.center.y + translation.y) 

       print("the translation x:\(translation.x) & y:\(newCenter.y)") 

       if (newCenter.y >= 397 && newCenter.y <= 632) { 
        recognizer.view!.center = newCenter 
        recognizer.setTranslation(CGPointZero, inView: self.view)} 

      default : break } 


} 

Answer 1

因爲我不知道你的代碼的其他部分，這是假設你有什麼可能，應該在節看起來像：

class ViewController: UIViewController { 

// Gesture function 
func panAround(recognizer: UIPanGestureRecognizer) { 
    switch recognizer.state { 
    ... 
    case .Changed: 
     let translation = recognizer.translationInView(yourView) 
     let newCenter = CGPointMake(self.view.bounds.size.width/2, 
       recognizer.view!.center.y + translation.y) 

     print("the translation x:\(translation.x) & y:\(newCenter.y)") 

     if (newCenter.y >= 397 && newCenter.y <= 632) { 
      recognizer.view!.center = newCenter 

      // Updating the UI whenever there is a "small change" 
      updateUI() 

      recognizer.setTranslation(CGPointZero, inView: self.view) 
     } 
    ... 
    } 
} 

private func updateUI() { 
    yourView.setNeedsDisplay() 
} 

注：上面的代碼不會被複制和粘貼直接工作，我只是指出在那裏你可以進行調整。