Question

我试图像这样创建自己的ScrollableImageView：

@interface ZoomableImageScrollView : UIScrollView <UIScrollViewDelegate>

@property (strong, nonatomic) UIImageView *imageView;
- (void)setImage:(UIImage *)image;

@end

@implementation ZoomableImageScrollView

- (void)awakeFromNib
{
    self.imageView = [[UIImageView alloc] initWithFrame:self.bounds];

    // Finally
    [self addSubview:self.imageView];
    self.delegate = self;
}

- (void)setImage:(UIImage *)image
{
    self.imageView.image = image;
    self.imageView.frame = (CGRect){.origin = CGPointZero, .size = image.size};
    self.contentSize = image.size;

    CGRect scrollViewFrame = self.frame;
    CGFloat scaleWidth = scrollViewFrame.size.width / self.contentSize.width;
    CGFloat scaleHeight = scrollViewFrame.size.height / self.contentSize.height;
    CGFloat minScale = MIN(scaleWidth, scaleHeight);

    self.minimumZoomScale = minScale;
    self.maximumZoomScale = 4;
    self.zoomScale = 1;
}

- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
    return self.imageView;
}

- (void)scrollViewWillBeginZooming:(UIScrollView *)scrollView withView:(UIView *)view
{
    NSLog(@"start!!");
}

- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(CGFloat)scale
{
    NSLog(@"here!!");
}

- (void)scrollViewDidZoom:(UIScrollView *)scrollView
{
    NSLog(@"DidZoom");
}

@end

然后，我在其他viewControllers中创建了这个scrollView，设置了image，尝试缩放，但它从未遇到过3个最后一个委托方法。有人可以解释为什么这不起作用吗？如果我在viewController中使用这些行，它实际上就是这样。这是否意味着UIView无法实现某些协议，只有viewController才能实现？

最后，利用这些东西的最佳做法是什么？就像，我想创建可重复使用的可滚动图像视图。

为什么这个ScrollableImageView不起作用？

0 个答案: