如何在放大滚动视图Objective-C时聚焦特定视图

Posted 2023-03-11

【中文标题】如何在放大滚动视图Objective-C时聚焦特定视图

【英文标题】：How to focus specific view while zooming in scrollview Objective-C

【发布时间】：2016-10-30 12:15:47

【问题描述】：

我在 ios 应用程序中工作，其中我在滚动视图中有多个内部视图，并且我在滚动视图中启用了分页，用户还可以缩放滚动视图可以近距离查看内部视图。一切正常，但发生的事情是导航功能一一突出显示每个内部视图，但在缩放时我无法专注于每个视图。内部视图可以是文本字段、按钮和简单视图，并且可以添加到滚动视图中，例如 [scrollview addSubview:myImageView];。

下面是我导航缩放滚动视图焦点的代码，但这不能正常工作：

- (void)showVisibleRectInZoom:(UIView*)objectToNavigate

    CGFloat zoomedScaleValue =myScroll.zoomScale;

    CGPoint pointToMove = CGPointMake(0.0, 0.0);

    if (zoomedScaleValue > 1.0) 

        [myScroll scrollRectToVisible:objectToNavigate.frame animated:YES];

    

寻求帮助如何为每个内部视图设置滚动视图可见位置。谢谢。

【参考方案1】：

试试这些：

我认为这段代码会对你有所帮助：

- (id)initWithImage:(UIImage *)image 
self = [super initWithImage:image];
if (self) 
    [self setUserInteractionEnabled:YES];

    UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleSingleTap:)];
    UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleDoubleTap:)];
    UITapGestureRecognizer *twoFingerTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTwoFingerTap:)];

    [doubleTap setNumberOfTapsRequired:2];
    [twoFingerTap setNumberOfTouchesRequired:2];

    [self addGestureRecognizer:singleTap];
    [self addGestureRecognizer:doubleTap];
    [self addGestureRecognizer:twoFingerTap];

    [singleTap release];
    [doubleTap release];
    [twoFingerTap release];

return self;
 

#pragma mark Private

  - (void)handleSingleTap:(UIGestureRecognizer *)gestureRecognizer 
if ([delegate respondsToSelector:@selector(tapDetectingImageView:gotSingleTapAtPoint:)])
    [delegate tapDetectingImageView:self gotSingleTapAtPoint:[gestureRecognizer locationInView:self]];
  

  - (void)handleDoubleTap:(UIGestureRecognizer *)gestureRecognizer 
if ([delegate respondsToSelector:@selector(tapDetectingImageView:gotDoubleTapAtPoint:)])
    [delegate tapDetectingImageView:self gotDoubleTapAtPoint:[gestureRecognizer locationInView:self]];
   

   - (void)handleTwoFingerTap:(UIGestureRecognizer *)gestureRecognizer 
if ([delegate respondsToSelector:@selector(tapDetectingImageView:gotTwoFingerTapAtPoint:)])
    [delegate tapDetectingImageView:self gotTwoFingerTapAtPoint:[gestureRecognizer locationInView:self]];
    

查看更多：How to zoom into a selected area of image in iPhone?

问题是我没有定义缩放代理 - 请参阅 viewForZoomingInScrollView（页面底部）：

https://developer.apple.com/library/ios/documentation/uikit/reference/uiscrollviewdelegate_protocol/Reference/UIScrollViewDelegate.html#//apple_ref/occ/intfm/UIScrollViewDelegate/viewForZoomingInScrollView

当我切换到 Xamarin 框架时，我在 Objective C 中没有代码片段。但是 C# 解决方案如下：

scrollView.ViewForZoomingInScrollView = delegate (UIScrollView sv)  return imageView; ;

其中 imageView 是包含要滚动的图像的 UIImageView。

发件人：Programatically zooming into small area of larger picture using UIScrollView