缩放后 UIImageView 在 PageControl 的右侧被切断

Posted 2023-03-11

【中文标题】缩放后 UIImageView 在 PageControl 的右侧被切断

【英文标题】：UIImageView is cut off on right side within PageControl after zooming

【发布时间】：2013-05-09 18:48:24

【问题描述】：

放大后我的图像在右侧被切断。如果我没有使用 cgrect make 设置偏移量，那么它不会被切断，但我希望我的图像在屏幕上居中。缩放后如何使图像居中而不切断正确的部分？

- (void)viewDidLoad 
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.

self.view.backgroundColor = [UIColor grayColor];

UIScrollView *mainScrollView = [[UIScrollView alloc] initWithFrame:self.view.bounds];
mainScrollView.pagingEnabled = YES;
mainScrollView.showsHorizontalScrollIndicator = NO;
mainScrollView.showsVerticalScrollIndicator = NO;

CGRect innerScrollFrame = mainScrollView.bounds;

for (NSInteger i = 0; i < 2; i++) 
    UIImageView *imageForZooming = [[UIImageView alloc] initWithImage:[UIImage imageNamed:[NSString stringWithFormat:@"page%d", i + 1]]];
    imageForZooming.tag = VIEW_FOR_ZOOM_TAG;
    imageForZooming.frame = CGRectMake(50, 0, imageForZooming.bounds.size.width, imageForZooming.bounds.size.height);

    UIScrollView *pageScrollView = [[UIScrollView alloc] initWithFrame:innerScrollFrame];
    pageScrollView.minimumZoomScale = 0.5f;
    pageScrollView.maximumZoomScale = 1.0f;
    pageScrollView.contentSize = imageForZooming.bounds.size;
    pageScrollView.delegate = self;
    [pageScrollView addSubview:imageForZooming];

    [mainScrollView addSubview:pageScrollView];

    if (i < 1) 
        innerScrollFrame.origin.x += innerScrollFrame.size.width;
    

    pageScrollView.zoomScale = 0.5f;


mainScrollView.contentSize = CGSizeMake(innerScrollFrame.origin.x + innerScrollFrame.size.width, mainScrollView.bounds.size.height);

[self.view addSubview:mainScrollView];


- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView 
return [scrollView viewWithTag:VIEW_FOR_ZOOM_TAG];

编辑：这是我的视图层次结构

查看 主滚动视图 innerScrollFrame pageScrollView imageForZooming innerScrollFrame pageScrollView imageForZooming

【参考方案1】：

对于以后遇到同样问题的其他人，我所做的是添加以下 UIScrollViewDelegate 协议：

- (void)scrollViewDidZoom:(UIScrollView *)scrollView 
    UIView *subView = [scrollView.subviews objectAtIndex:0];
    CGFloat offsetX = (scrollView.bounds.size.width > scrollView.contentSize.width) ? (scrollView.bounds.size.width - scrollView.contentSize.width) * 0.5 : 0.0;
    CGFloat offsetY = (scrollView.bounds.size.height > scrollView.contentSize.height) ? (scrollView.bounds.size.height - scrollView.contentSize.height) * 0.5 : 0.0;
    subView.center = CGPointMake(scrollView.contentSize.width * 0.5 + offsetX, 
        scrollView.contentSize.height * 0.5 + offsetY);

我在这里找到了答案：Center content of UIScrollView when smaller

以便图像在缩放后居中，而不是应用最初应用的偏移量。像魅力一样工作。现在，当我缩放时，我的图像在任一页面控件上都不会被截断，并且我可以在视图的开头将图像居中。