Swift iOS 8.0 - 在函数 rollViewDidEndDecelerating() 内调用时动画不起作用

Question

我在名为 animateImages 的函数内有一个动画:

func animateImagesIn(step: Int){
  if step == 0{
    let bounds = self.guideView.stepOne.bounds
    UIView.animateWithDuration(1.0, delay: 0.2, usingSpringWithDamping: 0.2, initialSpringVelocity: 10, options: nil, animations: {
            self.guideView.stepOne.bounds = CGRect(x: bounds.origin.x - 20, y: bounds.origin.y, width: bounds.size.width + 60, height: bounds.size.height)
            }, completion: nil)
  }

  if step == 1{
    let boundsOne = self.guideView.stepTwoLeft.bounds
    let boundsTwo = self.guideView.stepTwoRight.bounds
    UIView.animateWithDuration(1.0, delay: 0.2, usingSpringWithDamping: 0.2, initialSpringVelocity: 10, options: nil, animations: {
      self.guideView.stepTwoLeft.bounds = CGRect(x: boundsOne.origin.x + 20 , y: boundsOne.origin.y, width: boundsOne.size.width + 60, height: boundsOne.size.height)
      self.guideView.stepTwoRight.bounds = CGRect(x: boundsTwo.origin.x + 20 , y: boundsTwo.origin.y, width: boundsTwo.size.width + 60, height: boundsTwo.size.height)
    }, completion: nil)
  }
}

如果我在添加到 ScrollView 之前从 viewDidAppear 调用该函数，它会起作用:

for index in 0...currentDictionary.count-1{     
  println("dictionary index \(index)")

  guideView = GuideView()
  var guide = currentDictionary["\(index)"]

  guideView.frame = CGRectMake(xLoc, heightOffset, width, height-heightOffset)
  guideView.title.text = guide?.title.text
  guideView.subtitle.text = guide?.description.text

  if index == 0{
    guideView.stepOne.image = UIImage(named: "step1")
    guideView.stepOne.contentMode = .ScaleAspectFit
    animateImagesIn(index)
  }

  if index == 1{
    guideView.stepTwoLeft.image = UIImage(named: "giving hand")
    guideView.stepTwoRight.image = UIImage(named: "receiving hand")
    animateImagesIn(index)
  }

  scrollView.addSubview(guideView)
  xLoc = xLoc + (width)
}

但是如果我在 scrollViewDidEndDecelerating() 中调用它，它不会:

func scrollViewDidEndDecelerating(scrollView: UIScrollView) {
  var currentIndex = scrollView.contentOffset.x/UIScreen.mainScreen().bounds.width

  for subIndex in 0...currentDictionary.count-1{
    if (Int(currentIndex) == subIndex){
      createCarousel(Int(currentIndex))
      animateImagesIn(Int(currentIndex))
    }
  }
}

请告诉我哪里错了？谢谢!

Answer 1

您连接了委托(delegate)吗？

添加

scrollView.delegate = self

在viewDidLoad中，如果你忘记了