如何连续旋转图像

Question

我有一个.png格式的轮子图像,我想知道我怎么能动画,以便它连续旋转,我搜索stackoverflow并找到某些代码片段,帮助我旋转我的图像,但它不会连续旋转,它会只需旋转几秒钟即可停止,代码如下

viewdidload中的代码

UIImageView *imageToMove =
[[UIImageView alloc] initWithImage:[UIImageimageNamed:@"horo_circle.png"]];
[self.view addSubview:imageToMove];

[self rotateImage:imageToMove duration:5.0 
            curve:UIViewAnimationCurveEaseIn degrees:180];

和动画

- (void)rotateImage:(UIImageView *)image duration:(NSTimeInterval)duration 
          curve:(int)curve degrees:(CGFloat)degrees
{
    // Setup the animation
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:duration];
    [UIView setAnimationCurve:curve];
    [UIView setAnimationBeginsFromCurrentState:YES];

    // The transform matrix
    CGAffineTransform transform = 
    CGAffineTransformMakeRotation(DEGREES_TO_RADIANS(degrees));
    image.transform = transform;

    // Commit the changes
    [UIView commitAnimations];
}

以及导入后的以下行

#define M_PI   3.14159265358979323846264338327950288   /* pi */

#define DEGREES_TO_RADIANS(angle) (angle / 180.0 * M_PI)

Answer 1

你最好用以下方法做到这一点CABasicAnimation:

if ([self.spinnerOverlay animationForKey:@"SpinAnimation"] == nil) {
    CABasicAnimation* animation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
    animation.fromValue = [NSNumber numberWithFloat:0.0f];
    animation.toValue = [NSNumber numberWithFloat: 2*M_PI];
    animation.duration = 10.0f;
    animation.repeatCount = INFINITY;
    [self.spinnerOverlay.layer addAnimation:animation forKey:@"SpinAnimation"];
}

在这段代码中,我检查动画是否全部准备就绪,不需要再次设置.该spinnerOverlay是在你的情况下,UIImageView要旋转.

要停止动画:

  [self.spinnerOverlay.layer removeAnimationForKey:@"SpinAnimation"];