Question

我将钟表臂指向12点钟到当前时间。如果是，11点，我想让手臂顺时针旋转到11点位置。但当然如果我使用：

 CGAffineTransform rotation = CGAffineTransformMakeRotation(2*M_PI*11/12);

 [UIView animateWithDuration:3.0
                  animations:^{
                         clockArm.transform = rotation;
                     }];

旋转逆时针旋转。我试过了：

CGFloat angle = 2*M_PI*11/12;
CGAffineTransform firstRotation = CGAffineTransformMakeRotation(M_PI-0.001);
CGFloat firstRotationTime = 3.0*(M_PI/angle);
CGAffineTransform secondRotation = CGAffineTransformMakeRotation(angle);
CGFloat secondRotationTime = 3.0 - firstRotationTime;

[UIView animateWithDuration:firstRotationTime
                      delay:0.0
                    options:UIViewAnimationCurveLinear
                 animations:^{
                         self.clockArm1.transform = firstRotation;
                     }
                 completion:^(BOOL finished) {
                     [UIView animateWithDuration:secondRotationTime
                                           delay:0.0
                                         options:UIViewAnimationCurveLinear
                                      animations:^{
                                          self.clockArm1.transform = secondRotation;
                                      }
                                      completion:^(BOOL finished){
                                      }];
                 }];

动画确实是顺时针方向，但它很不稳定 - 动画似乎仍在为第一个动画做一个UIViewAnimationEaseInOut。我做错了什么，或者有其他方法可以实现我想要的目标吗？

Answer 1

您可以使用CATransaction的完成块在动画结束时设置视图的旋转属性。以下函数在我的测试用例中起作用：

- (void) rotateViewAnimated:(UIView*)view
               withDuration:(CFTimeInterval)duration
                    byAngle:(CGFloat)angle
{
    [CATransaction begin];
    CABasicAnimation *rotationAnimation;
    rotationAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
    rotationAnimation.byValue = [NSNumber numberWithFloat:angle];
    rotationAnimation.duration = duration;
    rotationAnimation.removedOnCompletion = YES;

    [CATransaction setCompletionBlock:^{
        view.transform = CGAffineTransformRotate(view.transform, angle);
    }];

    [view.layer addAnimation:rotationAnimation forKey:@"rotationAnimation"];
    [CATransaction commit];
}

你像

一样使用它

[self rotateViewAnimated:self.clockArm1 withDuration:3.0 byAngle:2*M_PI*11./12.];

Answer 2

感谢@Martin R的接受答案。我编辑了一下：

我替换了这一行

rotationAnimation.removedOnCompletion = YES;

这两行：

rotationAnimation.removedOnCompletion = NO;
rotationAnimation.fillMode = kCAFillModeForwards;

然后，在CompletionBlock中，我又添加了一行：

[view.layer removeAllAnimations];

所以，代码最终成为：

    - (void) rotateViewAnimated:(UIView*)view
           withDuration:(CFTimeInterval)duration
                byAngle:(CGFloat)angle
    {
        [CATransaction begin];
        CABasicAnimation *rotationAnimation;
        rotationAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
        rotationAnimation.byValue = [NSNumber numberWithFloat:angle];
        rotationAnimation.duration = duration;
        // changed by me
        rotationAnimation.removedOnCompletion = NO;
        rotationAnimation.fillMode = kCAFillModeForwards;


        [CATransaction setCompletionBlock:^{
        view.transform = CGAffineTransformRotate(view.transform, angle);
        // added by me
        [view.layer removeAllAnimations]; // this is important

        }];

    [view.layer addAnimation:rotationAnimation forKey:@"rotationAnimation"];
    [CATransaction commit];

    }

我的推荐来自：

1，https://stackoverflow.com/a/3586433/2481444

2，After rotating a CALayer using CABasicAnimation the layer jumps back to it's unrotated position

Answer 3

正如评论中所述，试试这个iphone UIImageView rotation 或UIView Infinite 360 degree rotation animation?

#import <QuartzCore/QuartzCore.h>

- (void) runSpinAnimationWithDuration:(CGFloat) duration;
{
    CABasicAnimation* rotationAnimation;
    rotationAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
    rotationAnimation.toValue = [NSNumber numberWithFloat: M_PI * 2.0 /* full rotation*/ * rotations * duration ];
    rotationAnimation.duration = duration;
    rotationAnimation.cumulative = YES;
    rotationAnimation.repeatCount = 1.0; 
    rotationAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];

    [myView.layer addAnimation:rotationAnimation forKey:@"rotationAnimation"];
}

顺时针旋转UIView大于180度的角度

3 个答案: