IOS：仅使用多点触控缩放 uiscrollview

Posted 2023-03-16

【中文标题】IOS：仅使用多点触控缩放 uiscrollview

【英文标题】：IOS: zoom for a uiscrollview only with multitouch

【发布时间】：2012-02-13 16:21:13

【问题描述】：

我有这个代码：

[scrollView setMinimumZoomScale:1.00];
[scrollView setMaximumZoomScale:2.00];
scrollView.delegate=self;

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event 

   NSSet *allTouches = [event allTouches];
    if ([allTouches count] == 2) 

        NSLog(@"multitouch");
        zoomMultiTouch = TRUE;


    

     else if ([allTouches count] == 1)

        NSLog(@"single touch");
        zoomMultiTouch = FALSE;
    

     else return;




- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event 


    if (zoomMultiTouch)
        scrollView.userInteractionEnabled = YES;
        scrollView.scrollEnabled = YES;
        NSLog(@"zoomMultitouch moved");
    

    else 
        scrollView.userInteractionEnabled = NO;
        scrollView.scrollEnabled = NO;
        NSLog(@"NOzoom moved");
    

  //some code for coloring an image



- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event 
    scrollView.userInteractionEnabled = NO;
    scrollView.scrollEnabled = NO;
    zoomMultiTouch = FALSE;

如您所见，我想用里面的图像缩放滚动视图；当我用手指触摸滚动视图时，我会为图像着色，而不是当我用两根手指触摸滚动视图时，我想对其进行缩放，如果我用手指触摸，则必须禁用 zomm。 用我的代码不会发生；它可以识别双击但不主动缩放，为什么？

【参考方案1】：

我认为问题在于您没有实现所有必需的缩放委托方法。

The UIScrollView class can have a delegate that must adopt the UIScrollViewDelegate protocol. For zooming and panning to work, the delegate must implement both viewForZoomingInScrollView: and scrollViewDidEndZooming:withView:atScale:; in addition, the maximum (maximumZoomScale) and minimum ( minimumZoomScale) zoom scale must be different.

希望对你有帮助。

UIScrollView Class Reference