Question

我的图像在放大后在右侧被切断。如果我没有用cgrect make设置偏移，那么它不会被切断，但我希望我的图像在屏幕上居中。如何让我的图像居中，而不是在缩放后切掉右边的部分？

- (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
- mainScrollView
  - innerScrollFrame
    - pageScrollView
      - imageForZooming
  - innerScrollFrame
    - pageScrollView
      - imageForZooming

Answer 1

对于将来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);
}

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

使图像在缩放后居中，而不是应用最初应用的偏移。像魅力一样工作。现在当我缩放时，我的图像都没有在任一页面控件上被切断，我可以将图像置于视图的开头。

缩放后，PageControl内的UIImageView在右侧被切断

1 个答案: