Question

使用OS 3.1我在UIScrollView中放置了一个点击检测图像视图（取自Apple的Scroll View套件样本），并且想要在图像视图出现时进行两次缩放。第一个缩放是使整个图像可见，第二个缩放是放大到指定区域。我现在拥有的是：

- (void)viewDidLoad {
    // After adding scroll view and image view
    imageScrollView.minimumZoomScale = 0.5;
    imageScrollView.maximumZoomScale = 2.75;
    imageScrollView.zoomScale = 1.0;
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:1];    
    [UIView setAnimationBeginsFromCurrentState:YES];
    [UIView setAnimationDelegate: self];
    [imageScrollView zoomToRect:[imageView frame] animated:YES];
    [UIView commitAnimations];

和以下内容检测第一次缩放的结束并触发第二次：

- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale {
    selectedRect.origin.x = 60.0;
    selectedRect.origin.y = 90.0;
    selectedRect.size.width = 90.0;
    selectedRect.size.height = 90.0;

    imageScrollView.minimumZoomScale = 1.0;
    imageScrollView.maximumZoomScale = 2.75;
    imageScrollView.zoomScale = 2.5;
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:1];    
    [UIView setAnimationBeginsFromCurrentState:YES];
    [UIView setAnimationDelegate: self];
    [imageScrollView zoomToRect:selectedRect animated:YES];
    [UIView commitAnimations];

这会导致无限循环并且滚动视图在两个放大点之间反复“摆动”。我应该做些什么呢？谢谢。

Answer 1

当然，您只需将当前的zoomScale检查为scrollViewDidEndZooming中的第一个动作。如果您已放大，请不要进行新的缩放。

背靠背UIScrollView缩放

1 个答案: