iphone - 在 UIScrollView 中缩放 UIImageView 越界

Question

我已经在我的 UIScrollView 中成功实现了 UIImageView 的缩放，但是我遇到了一个令我恼火的奇怪问题。

基本上，当我放大图像时

我可以平移 View 以实际滚动出图像边界，然后我会留下一个黑色区域，如下所示:

当我放大得更多时，我可以让黑色边框填满整个屏幕!同时，在 iPhone 照片应用程序中，您无法缩小实际图像。我的实现有什么问题？

看起来像这样:

UIImage *imageToDisplay = [UIImage imageWithData:tmpImageData];
imageViewMain.image = imageToDisplay;
imageViewMain.frame = CGRectMake(0, 0, scrollViewMain.frame.size.width, scrollViewMain.frame.size.height);
imageViewMain.contentMode = UIViewContentModeScaleAspectFit;

scrollViewMain.delegate = self;
scrollViewMain.minimumZoomScale = 1.0;
scrollViewMain.maximumZoomScale = 9.0;
scrollViewMain.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
scrollViewMain.contentSize = imageViewMain.frame.size;

[self.view addSubview:scrollViewMain];
[scrollViewMain addSubview:imageViewMain];

我也实现了这个方法:

- (UIView*)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
    return imageViewMain;
}

提前致谢!

编辑:当我第一次加载 View 时，我缩小了 UIImageView 以适应 ScrollView ，图像看起来像这样:

Answer 1

只需尝试这段代码....在需要的地方更改一些代码...为您的UIImageView 使用UIPinchGestureRecognizer，然后将此图像添加到您的UIScrollView 像下面这样..

UIImageView *img = [[UIImageView alloc]init];
img.image = [UIImage imageWithData:tmpImageData];
img.userInteractionEnabled = YES;
img.frame = CGRectMake(210,100, 200, 200);/// define frame which you want...
[img sizeToFit];

UIPinchGestureRecognizer *pinchRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(scale:)];
[pinchRecognizer setDelegate:self];
[img addGestureRecognizer:pinchRecognizer];
[pinchRecognizer release];
[scrollViewMain addSubview:img];
[scrollViewMain bringSubviewToFront:img];
[img release]; 

然后将下面的代码粘贴到您的 .m 文件中...

#pragma mark GestureRecognizer Methods
-(void)scale:(id)sender 
{
    UIView *imgTempGest = [sender view];
    if([(UIPinchGestureRecognizer*)sender state] == UIGestureRecognizerStateEnded) 
    {
        lastScale = 1.0;
        return;
    }
    CGFloat scale = 1.0 - (lastScale - [(UIPinchGestureRecognizer*)sender scale]);

    CGAffineTransform currentTransform = [(UIPinchGestureRecognizer*)sender view].transform;
    CGAffineTransform newTransform = CGAffineTransformScale(currentTransform, scale, scale);

    [[(UIPinchGestureRecognizer*)sender view] setTransform:newTransform];

    [imgTempGest setTransform:newTransform];

    lastScale = [(UIPinchGestureRecognizer*)sender scale];
}

对于 LastScale，只需在 .h 文件中定义该变量，如下所示...

CGFloat lastScale;

希望对你有帮助...