创建动画

- (CABasicAnimation *)spinAnimationWithDuration:(CGFloat)duration clockwise:(BOOL)clockwise repeat:(BOOL)repeats
{
    CABasicAnimation *anim = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
    anim.toValue = clockwise ? @(M_PI * 2.0) : @(M_PI * -2.0);
    anim.duration = duration;
    anim.cumulative = YES;
    anim.repeatCount = repeats ? CGFLOAT_MAX : 0;
    return anim;
}

将它添加到这样的视图中

CABasicAnimation *animation = [self spinAnimationWithDuration:1.0 clockwise:YES repeat:YES];
[self.spinningView.layer addAnimation:animation forKey:@"rotationAnimation"];

这个答案有什么不同?如果你的大部分函数都返回对象，而不是在这里和那里操作一些对象，你会有更干净的代码。

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()
        }
    })
}

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。

你也可以用UIView和block做同样类型的动画。下面是一个类扩展方法，它可以以任何角度旋转视图。

- (void)rotationWithDuration:(NSTimeInterval)duration angle:(CGFloat)angle options:(UIViewAnimationOptions)options
{
    // Repeat a quarter rotation as many times as needed to complete the full rotation
    CGFloat sign = angle > 0 ? 1 : -1;
    __block NSUInteger numberRepeats = floorf(fabsf(angle) / M_PI_2);
    CGFloat quarterDuration = duration * M_PI_2 / fabs(angle);

    CGFloat lastRotation = angle - sign * numberRepeats * M_PI_2;
    CGFloat lastDuration = duration - quarterDuration * numberRepeats;

    __block UIViewAnimationOptions startOptions = UIViewAnimationOptionBeginFromCurrentState;
    UIViewAnimationOptions endOptions = UIViewAnimationOptionBeginFromCurrentState;

    if (options & UIViewAnimationOptionCurveEaseIn || options == UIViewAnimationOptionCurveEaseInOut) {
        startOptions |= UIViewAnimationOptionCurveEaseIn;
    } else {
        startOptions |= UIViewAnimationOptionCurveLinear;
    }

    if (options & UIViewAnimationOptionCurveEaseOut || options == UIViewAnimationOptionCurveEaseInOut) {
        endOptions |= UIViewAnimationOptionCurveEaseOut;
    } else {
        endOptions |= UIViewAnimationOptionCurveLinear;
    }

    void (^lastRotationBlock)(void) = ^ {
        [UIView animateWithDuration:lastDuration 
                              delay:0 
                            options:endOptions 
                         animations:^{
                             self.transform = CGAffineTransformRotate(self.transform, lastRotation);
                         } 
                         completion:^(BOOL finished) {
                             NSLog(@"Animation completed");   
                         }
         ];
    };

    if (numberRepeats) {
        __block void (^quarterSpinningBlock)(void) = ^{ 
            [UIView animateWithDuration:quarterDuration 
                                  delay:0 
                                options:startOptions 
                             animations:^{
                                 self.transform = CGAffineTransformRotate(self.transform, M_PI_2);
                                 numberRepeats--; 
                             } 
                             completion:^(BOOL finished) {
                                 if (numberRepeats > 0) {
                                     startOptions = UIViewAnimationOptionBeginFromCurrentState | UIViewAnimationOptionCurveLinear;
                                     quarterSpinningBlock();
                                 } else {
                                     lastRotationBlock();
                                 }NSLog(@"Animation completed");   
                             }
             ];

        };

        quarterSpinningBlock();
    } else {
        lastRotationBlock();
    }
}

@ram的回答很有帮助。以下是Swift版本的答案。

斯威夫特2

private func rotateImageView() {

    UIView.animateWithDuration(1, delay: 0, options: UIViewAnimationOptions.CurveLinear, animations: { () -> Void in
        self.imageView.transform = CGAffineTransformRotate(self.imageView.transform, CGFloat(M_PI_2))
        }) { (finished) -> Void in
            if finished {
                self.rotateImageView()
            }
    }
}

斯威夫特3、4、5所示

private func rotateImageView() {

    UIView.animate(withDuration: 1, delay: 0, options: UIView.AnimationOptions.curveLinear, animations: { () -> Void in
        self.imageView.transform = self.imageView.transform.rotated(by: .pi / 2)
    }) { (finished) -> Void in
        if finished {
            self.rotateImageView()
        }
    }
}

我的贡献与一个快速扩展从检查解决方案:

斯威夫特4.0

extension UIView{
    func rotate() {
        let rotation : CABasicAnimation = CABasicAnimation(keyPath: "transform.rotation.z")
        rotation.toValue = NSNumber(value: Double.pi * 2)
        rotation.duration = 1
        rotation.isCumulative = true
        rotation.repeatCount = Float.greatestFiniteMagnitude
        self.layer.add(rotation, forKey: "rotationAnimation")
    }
}

弃用:

extension UIView{
    func rotate() {
        let rotation : CABasicAnimation = CABasicAnimation(keyPath: "transform.rotation.z")
        rotation.toValue = NSNumber(double: M_PI * 2)
        rotation.duration = 1
        rotation.cumulative = true
        rotation.repeatCount = FLT_MAX
        self.layer.addAnimation(rotation, forKey: "rotationAnimation")
    }
}