我试图旋转一个UIImageView 360度,并在网上看了几个教程。我不能让它们都工作,UIView要么停止,要么跳转到一个新位置。

我怎样才能做到这一点呢?

我最近尝试的是:

[UIView animateWithDuration:1.0
                      delay:0.0
                    options:0
                 animations:^{
                     imageToMove.transform = CGAffineTransformMakeRotation(M_PI);
                 } 
                 completion:^(BOOL finished){
                     NSLog(@"Done!");
                 }];

但如果我使用2*pi,它根本不会移动(因为它是相同的位置)。如果我尝试只做(180度),它可以工作,但如果我再次调用这个方法,它会向后旋转。

编辑:

[UIView animateWithDuration:1.0
                      delay:0.0
                    options:0
                 animations:^{
                     [UIView setAnimationRepeatCount:HUGE_VALF];
                     [UIView setAnimationBeginsFromCurrentState:YES];
                     imageToMove.transform = CGAffineTransformMakeRotation(M_PI);
                 } 
                 completion:^(BOOL finished){
                     NSLog(@"Done!");
                 }];

也不管用。它会转到180度,暂停一秒钟,然后在重新开始之前重置回0度。


当前回答

斯威夫特4,

func rotateImage(image: UIImageView) {
        UIView.animate(withDuration: 1, animations: {
            image.transform = CGAffineTransform(rotationAngle: CGFloat.pi)
            image.transform = CGAffineTransform.identity
        }) { (completed) in
            self.rotateImage()
        }
    }

Ref

其他回答

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。

let val = CGFloat(M_PI_2)

UIView.animate(withDuration: 1, delay: 0, options: [.repeat, .curveLinear], animations: {
        self.viewToRotate.transform = self.viewToRotate.transform.rotated(by: val)
})

这就是我如何向正确的方向旋转360度。

[UIView animateWithDuration:1.0f delay:0.0f options:UIViewAnimationOptionRepeat|UIViewAnimationOptionCurveLinear
                     animations:^{
                         [imageIndView setTransform:CGAffineTransformRotate([imageIndView transform], M_PI-0.00001f)];
                     } completion:nil];

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。

Swift 5使用关键帧动画的UIView扩展

这个方法允许我们直接使用UIView.AnimationOptions.repeat

public extension UIView {

    func animateRotation(duration: TimeInterval, repeat: Bool, completion: ((Bool) -> ())?) {

        var options = UIView.KeyframeAnimationOptions(rawValue: UIView.AnimationOptions.curveLinear.rawValue)

        if `repeat` {
            options.insert(.repeat)
        }

        UIView.animateKeyframes(withDuration: duration, delay: 0, options: options, animations: {

            UIView.addKeyframe(withRelativeStartTime: 0, relativeDuration: 0.25, animations: {
                self.transform = CGAffineTransform(rotationAngle: CGFloat.pi/2)
            })

            UIView.addKeyframe(withRelativeStartTime: 0.25, relativeDuration: 0.25, animations: {
                self.transform = CGAffineTransform(rotationAngle: CGFloat.pi)
            })

            UIView.addKeyframe(withRelativeStartTime: 0.5, relativeDuration: 0.25, animations: {
                self.transform = CGAffineTransform(rotationAngle: 3*CGFloat.pi/2)
            })

            UIView.addKeyframe(withRelativeStartTime: 0.75, relativeDuration: 0.25, animations: {
                self.transform = CGAffineTransform(rotationAngle: 2*CGFloat.pi)
            })

        }, completion: completion)

    }

}