Swift - UIView动画在首次运行后加速

Question

我正在为每个案例显示不同的动画，而它似乎正在加在一起并加速。我尝试使用stopAnimating（）以及removeAllAnimations（）。他们都没有工作。

        switch currentDrawType {
        case 0:
            for i in 0..<imageNames.count{
                images.append(UIImage(named: imageNames[i])!)
            }
            self.starImage.animationImages = images
            self.starImage.animationDuration = 0.5
        case 1:

            for a in 0..<imageA.count{
                images.append(UIImage(named: imageA[a])!)
            }
            self.starImage.animationImages = images
            self.starImage.animationDuration = 7.0
        case 2:
            for b in 0..<imageB.count{
                images.append(UIImage(named: imageB[b])!)
            }
            self.starImage.animationImages = images
            self.starImage.animationDuration = 0.5

        default:
            break
        }