iphone - 一个接一个地运行动画失败

Question

我正在尝试为图像设置动画，使其在被选中时左右旋转，基本上是为了让用户了解他们正在触摸的对象。

我找到了一些动画代码:

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

但是，当我尝试运行两个动画时，只有最后一个有效。即使有适当的延迟，也只会显示第二个动画:

[self rotateImage:self duration:.5 
                curve:UIViewAnimationCurveEaseIn degrees:60 delay:0];
    [self rotateImage:self duration:.5 
                curve:UIViewAnimationCurveEaseIn degrees:-60 delay:5];

我该怎么做才能创建动画，使其向左旋转，然后向右旋转？

Answer 1

[UIView animateWithDuration:0.2 animations:^{
// animation left
    [UIView setAnimationDelay:10];

    } completion:^(BOOL finished){

[UIView animateWithDuration:0.2 animations:^{
       // animation right
    } completion:^(BOOL finished){
       // done
    }];

    }];

在这里找到

https://developer.apple.com/library/content/featuredarticles/Short_Practical_Guide_Blocks/