如何在 UIScrollView 中捏缩放多个 UIImageView

Question

我必须捏缩放多个图像。我已将每个 UIImageView 添加到 UIView 并将 UIView 添加到 UIScrollView。并返回 UIView 图像 viewForZoomingInScrollView: 委托方法，但图像未按预期缩放。有没有更好的方法？

Answer 1

#define VIEW_FOR_ZOOM_TAG (1)

@implementation [SVViewController][1]

- (void)viewDidLoad {
    [super viewDidLoad];

    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 < 3; i++) {
        UIImageView *imageForZooming = [[UIImageView alloc] initWithImage:[UIImage imageNamed:  
        [NSString stringWithFormat:@"page%d", i + 1]]];
        imageForZooming.tag = VIEW_FOR_ZOOM_TAG;

        UIScrollView *pageScrollView = [[UIScrollView alloc] initWithFrame:innerScrollFrame];
        pageScrollView.minimumZoomScale = 1.0f;
        pageScrollView.maximumZoomScale = 2.0f;
        pageScrollView.zoomScale = 1.0f;
        pageScrollView.contentSize = imageForZooming.bounds.size;
        pageScrollView.delegate = self;
        pageScrollView.showsHorizontalScrollIndicator = NO;
        pageScrollView.showsVerticalScrollIndicator = NO;
        [pageScrollView addSubview:imageForZooming];

        [mainScrollView addSubview:pageScrollView];

        if (i < 2) {
            innerScrollFrame.origin.x += innerScrollFrame.size.width;
        }
    }

    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];
}

- (NSUInteger)supportedInterfaceOrientations {
    return UIInterfaceOrientationMaskPortrait;
} 

- (BOOL)shouldAutorotate {
    return NO;
}

@end


  [1]: http://www.lyricspoints.com

Answer 2

• 检查滚动视图的最小和最大缩放比例属性。 （max 应该大于 min 才能进行缩放）
• 确保您返回的是相应的 UIImageView 而不是 UIView
• 确保您已将滚动视图委托设置为您希望将滚动视图的委托消息发送到的对象，例如viewForZoomingInScrollView: