为什么不试试这个呢?

NSArray *animationFrames = [NSArray arrayWithObjects:
  [UIImage imageWithName:@"image1.png"],
  [UIImage imageWithName:@"image2.png"], 
  nil];

UIImageView *animatedImageView = [[UIImageView alloc] init];
animatedImageView.animationImages = animationsFrame;
[animatedImageView setAnimationRepeatCount:1];
[animatedImageView startAnimating];

快速版本:

let animationsFrames = [UIImage(named: "image1.png"), UIImage(named: "image2.png")]
let animatedImageView = UIImageView()
animatedImageView.animationImages = animationsFrames
animatedImageView.animationRepeatCount = 1
animatedImageView.startAnimating()

弗拉基米尔的答案是完美的，但任何像我这样正在寻找快速解决方案的人

该方案适用于swift 4.2版本

var i = 0
    func animation(){
        let name = (i % 2 == 0) ? "1.png" : "2.png"
        myImageView.image = UIImage.init(named: name)
        let transition: CATransition = CATransition.init()
        transition.duration = 1.0
        transition.timingFunction = CAMediaTimingFunction.init(name: .easeInEaseOut)
        transition.type = .fade
        myImageView.layer.add(transition, forKey: nil)
        i += 1
    }

您可以在任何地方调用此方法。它将改变图像到下一个(图像)与动画。

对于Swift 4.0版本使用波纹管解决方案

var i = 0
    func animationVersion4(){
        let name = (i % 2 == 0) ? "1.png" : "2.png"
        uiImage.image = UIImage.init(named: name)
        let transition: CATransition = CATransition.init()
        transition.duration = 1.0
        transition.timingFunction = CAMediaTimingFunction.init(name: kCAMediaTimingFunctionEaseInEaseOut)
        transition.type = kCATransitionFade
        uiImage.layer.add(transition, forKey: nil)
        i += 1
    }

这里有一些不同的方法:UIAnimations，在我看来，这听起来像是你的挑战。

编辑:我太懒了:)

在这篇文章中，我提到了这个方法:

[newView setFrame:CGRectMake( 0.0f, 480.0f, 320.0f, 480.0f)]; //notice this is OFF screen!
[UIView beginAnimations:@"animateTableView" context:nil];
[UIView setAnimationDuration:0.4];
[newView setFrame:CGRectMake( 0.0f, 0.0f, 320.0f, 480.0f)]; //notice this is ON screen!
[UIView commitAnimations];

但是不是动画帧，而是动画alpha:

[newView setAlpha:0.0]; // set it to zero so it is all gone.
[UIView beginAnimations:@"animateTableView" context:nil];
[UIView setAnimationDuration:0.4];
[newView setAlpha:0.5]; //this will change the newView alpha from its previous zero value to 0.5f
[UIView commitAnimations];

下面是Swift中的一个例子，它将首先交叉溶解一个新图像，然后添加一个弹性动画:

var selected: Bool {
  willSet(selected) {
    let expandTransform:CGAffineTransform = CGAffineTransformMakeScale(1.15, 1.15);
    if (!self.selected && selected) {
      UIView.transitionWithView(self.imageView,
        duration:0.1,
        options: UIViewAnimationOptions.TransitionCrossDissolve,
        animations: {
          self.imageView.image = SNStockCellSelectionAccessoryViewImage(selected)
          self.imageView.transform = expandTransform
        },
        completion: {(finished: Bool) in
          UIView.animateWithDuration(0.4,
            delay:0.0,
            usingSpringWithDamping:0.40,
            initialSpringVelocity:0.2,
            options:UIViewAnimationOptions.CurveEaseOut,
            animations: {
              self.imageView.transform = CGAffineTransformInvert(expandTransform)
            }, completion:nil)
      })
    }
  }
}

var imageView:UIImageView

如果imageView被正确地作为子视图添加到视图中，在selected = false到selected = true之间切换应该用一个弹性动画交换图像。SNStockCellSelectionAccessoryViewImage只是根据当前的选择状态返回一个不同的图像，如下所示:

private let SNStockCellSelectionAccessoryViewPlusIconSelected:UIImage = UIImage(named:"PlusIconSelected")!
private let SNStockCellSelectionAccessoryViewPlusIcon:UIImage = UIImage(named:"PlusIcon")!

private func SNStockCellSelectionAccessoryViewImage(selected:Bool) -> UIImage {
  return selected ? SNStockCellSelectionAccessoryViewPlusIconSelected : SNStockCellSelectionAccessoryViewPlusIcon
}

下面的GIF例子有点慢，实际的动画发生得更快:

我不确定你是否可以用渐隐效果动画UIViews，因为似乎所有支持的视图转换都在UIViewAnimationTransition枚举中定义。渐变效果可以使用CoreAnimation实现。该方法的示例示例:

#import <QuartzCore/QuartzCore.h>
...
imageView.image = [UIImage imageNamed:(i % 2) ? @"3.jpg" : @"4.jpg"];

CATransition *transition = [CATransition animation];
transition.duration = 1.0f;
transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
transition.type = kCATransitionFade;

[imageView.layer addAnimation:transition forKey:nil];

CABasicAnimation* fadeAnim = [CABasicAnimation animationWithKeyPath:@"contents"];
fadeAnim.fromValue = (__bridge id)imageView.image.CGImage;
fadeAnim.toValue = (__bridge id)[UIImage imageNamed:@"newImage.png"].CGImage;
fadeAnim.duration = 2.0;
[imageView.layer addAnimation:fadeAnim forKey:@"contents"];
imageView.layer.contents = (__bridge id)[UIImage imageNamed:@"newImage.png"].CGImage;