Swift3版本:

extension UIView {

    func startRotate() {
        let rotation : CABasicAnimation = CABasicAnimation(keyPath: "transform.rotation.z")
        rotation.fromValue = 0
        rotation.toValue = NSNumber(value: M_PI * 2)
        rotation.duration = 2
        rotation.isCumulative = true
        rotation.repeatCount = FLT_MAX
        self.layer.add(rotation, forKey: "rotationAnimation")
    }

    func stopRotate() {
        self.layer.removeAnimation(forKey: "rotationAnimation")
    }
}

记住在viewWillAppear中调用startRotate，而不是在viewDidLoad中。

Kudos to Richard J. Ross III for the idea, but I found that his code wasn't quite what I needed. The default for options, I believe, is to give you UIViewAnimationOptionCurveEaseInOut, which doesn't look right in a continuous animation. Also, I added a check so that I could stop my animation at an even quarter turn if I needed (not infinite, but of indefinite duration), and made the acceleration ramp up during the first 90 degrees, and decelerate during the last 90 degrees (after a stop has been requested):

// an ivar for your class:
BOOL animating;

- (void)spinWithOptions:(UIViewAnimationOptions)options {
   // this spin completes 360 degrees every 2 seconds
   [UIView animateWithDuration:0.5
                         delay:0
                       options:options
                    animations:^{
                       self.imageToMove.transform = CGAffineTransformRotate(imageToMove.transform, M_PI / 2);
                    }
                    completion:^(BOOL finished) {
                       if (finished) {
                          if (animating) {
                             // if flag still set, keep spinning with constant speed
                             [self spinWithOptions: UIViewAnimationOptionCurveLinear];
                          } else if (options != UIViewAnimationOptionCurveEaseOut) {
                             // one last spin, with deceleration
                             [self spinWithOptions: UIViewAnimationOptionCurveEaseOut];
                          }
                       }
                    }];
}

- (void)startSpin {
   if (!animating) {
      animating = YES;
      [self spinWithOptions: UIViewAnimationOptionCurveEaseIn];
   }
}

- (void)stopSpin {
    // set the flag to stop spinning after one last 90 degree increment
    animating = NO;
}

更新

我添加了处理请求重新开始旋转(startSpin)的能力，而之前的旋转正在结束(完成)。Github上的示例项目。

如果有人想要nates的解决方案，那么这里是一个粗略的swift翻译:

class SomeClass: UIViewController {

    var animating : Bool = false
    @IBOutlet weak var activityIndicatorImage: UIImageView!

    func startSpinning() {
        if(!animating) {
            animating = true;
            spinWithOptions(UIViewAnimationOptions.CurveEaseIn);
        }
    }

    func stopSpinning() {
        animating = false
    }

    func spinWithOptions(options: UIViewAnimationOptions) {
        UIView.animateWithDuration(0.5, delay: 0.0, options: options, animations: { () -> Void in
            let val : CGFloat = CGFloat((M_PI / Double(2.0)));
            self.activityIndicatorImage.transform = CGAffineTransformRotate(self.activityIndicatorImage.transform,val)
        }) { (finished: Bool) -> Void in

            if(finished) {
                if(self.animating){
                    self.spinWithOptions(UIViewAnimationOptions.CurveLinear)
                } else if (options != UIViewAnimationOptions.CurveEaseOut) {
                    self.spinWithOptions(UIViewAnimationOptions.CurveEaseOut)
                }
            }

        }
    }

    override func viewDidLoad() {
        startSpinning()
    }
}

我认为你最好添加一个UIVIew Category:

#import <QuartzCore/QuartzCore.h>
#import "UIView+Rotate.h"

实现UIView(旋转)

(void)remrotate360WithDuration:(CGFloat)duration repeatCount: (float)repeatCount { CABasicAnimation *fullRotation; fullRotation = [CABasicAnimation animationWithKeyPath:@"transform.rotation"]; fullRotation.fromValue = [NSNumber numberWithFloat:0]; fullRotation.toValue = [NSNumber numberWithFloat:(2*M_PI)]; // fullRotation.toValue = [NSNumber numberWithFloat:-(2*M_PI)]; // added this minus sign as i want to rotate it to anticlockwise fullRotation.duration = duration; fullRotation.speed = 2.0f; // Changed rotation speed if (repeatCount == 0) fullRotation.repeatCount = MAXFLOAT; else fullRotation.repeatCount = repeatCount; [self.layer addAnimation:fullRotation forKey:@"360"]; }

不使用此方法:)

(void)remstopAllAnimations { [self.layer removeAllAnimations]; }; (void)rempauseAnimations { [self rempauseLayer:self.layer]; } (void)remresumeAnimations { [self remresumeLayer:self.layer]; } (void)rempauseLayer:(CALayer *)layer { CFTimeInterval pausedTime = [layer convertTime:CACurrentMediaTime() fromLayer:nil]; layer.speed = 0.0; layer.timeOffset = pausedTime; } (void)remresumeLayer:(CALayer *)layer { CFTimeInterval pausedTime = [layer timeOffset]; layer.speed = 1.0; layer.timeOffset = 0.0; layer.beginTime = 0.0; CFTimeInterval timeSincePause = [layer convertTime:CACurrentMediaTime() fromLayer:nil] - pausedTime; layer.beginTime = timeSincePause; }

我已经开发了一个闪亮的动画框架，可以节省你的时间! 使用它可以很容易地创建这个动画:

private var endlessRotater: EndlessAnimator!
override func viewDidAppear(animated: Bool) 
{
    super.viewDidAppear(animated)
    let rotationAnimation = AdditiveRotateAnimator(M_PI).to(targetView).duration(2.0).baseAnimation(.CurveLinear)
    endlessRotater = EndlessAnimator(rotationAnimation)
    endlessRotater.animate()
}

要停止这个动画，只需将nil设置为endlessRotater。

如果你感兴趣，请看看:https://github.com/hip4yes/Animatics

斯威夫特4.0

func rotateImageView()
{
    UIView.animate(withDuration: 0.3, delay: 0, options: .curveLinear, animations: {() -> Void in
        self.imageView.transform = self.imageView.transform.rotated(by: .pi / 2)
    }, completion: {(_ finished: Bool) -> Void in
        if finished {
            rotateImageView()
        }
    })
}