Swift洗牌动画效果的实现方法

for _ in 0...49 {
        let cardSet = UIImageView(image: UIImage(named: "cardBackLandscape"))
        self.view.addSubview(cardSet)
        cardSet.frame = self.landscapeCardBack.frame
        self.cardSetList.append(cardSet)
      }
      NSNotificationCenter.defaultCenter().postNotificationName("setCreated", object: nil)

func shuffleTheSet() {
    self.shuffleButton.userInteractionEnabled = false
    let delayTime = dispatch_time(DISPATCH_TIME_NOW, Int64(0.5 * Double(NSEC_PER_SEC)))
    dispatch_after(delayTime, dispatch_get_main_queue()) {
      NSNotificationCenter.defaultCenter().postNotificationName("shuffleFinished", object: nil)
    }
    for count in 0...49 {
      UIView.animateWithDuration(0.3, animations: {
        let cardRotateAnimation = POPBasicAnimation(propertyNamed: kPOPLayerRotation)
        cardRotateAnimation.fromValue = 0
        cardRotateAnimation.toValue = CGFloat(M_PI * 2.0)
        cardRotateAnimation.duration = 1
        //        cardRotateAnimation.duration = Double(count>5 ? count/2 : count/10)
        cardRotateAnimation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionLinear)
        self.cardSetList[count].layer.pop_addAnimation(cardRotateAnimation, forKey: "cardRotation")
        self.cardSetList[count].frame.origin = CGPointMake(CGFloat(arc4random()) % (250 - 0 + 1) + 0, CGFloat(arc4random()) % (300 - 74 + 1) + 74)
        self.view.layoutIfNeeded()
        self.landscapeCardBack.removeFromSuperview()
      })
    }
  }

for count in 0...49 {
      UIView.animateWithDuration(0.3, animations: {
        self.cardSetList[count].center = self.landscapeCardBack.center
      })
      self.view.layoutIfNeeded()
    }
    self.shuffleButton.userInteractionEnabled = true
    self.shuffleButton.setTitle("Cut Card", forState: .Normal)