ios - 双指缩放在 ScrollView 中不起作用

Question

我可以滚动 ImageView ，但无法通过捏合来放大/缩小。哪里出错了？

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    UIImage *chosenImage = info[UIImagePickerControllerOriginalImage];

    UIImageView *imageView = [[UIImageView alloc] init];
    [self.scrollView addSubview:imageView];
    imageView.frame = CGRectMake(0, 0, chosenImage.size.width, chosenImage.size.height);

    imageView.image = chosenImage;

    self.scrollView.maximumZoomScale = 4;
    self.scrollView.minimumZoomScale = 0.1;
    self.scrollView.showsVerticalScrollIndicator=YES;
    self.scrollView.delegate = self;
    self.scrollView.scrollEnabled=YES;
    self.scrollView.userInteractionEnabled=YES;

    self.scrollView.contentSize = CGSizeMake(chosenImage.size.width, chosenImage.size.height);

    [picker dismissViewControllerAnimated:YES completion:NULL];
}

Answer 1

首先确保您的 View 实现了正确的委托(delegate)。比如在.m文件中

@interface myViewController () <UIGestureRecognizerDelegate, UIScrollViewDelegate>

UIScrollView 类可以有一个必须采用 UIScrollViewDelegate 协议(protocol)的委托(delegate)。为了缩放和平移工作，委托(delegate)必须同时实现 viewForZoomingInScrollView: 和 scrollViewDidEndZooming:withView:atScale:;此外，最大 (maximumZoomScale) 和最小 (minimumZoomScale) 缩放比例必须不同。

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




-(void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale
    {
    }