IOS:仅使用多点触控缩放 uiscrollview

Question

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，我想缩放带有图像的 scrollView；当我用手指触摸 scrollView 时我给图像上色，而不是当我用两个手指触摸 scrollview 时，我想对其进行缩放，如果我用手指触摸 zomm 之后必须禁用。 使用我的代码不会发生；它识别双击但不主动缩放，为什么？

Answer 1

我认为问题在于您没有实现所有必需的缩放委托(delegate)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.

希望对您有所帮助。

UIScrollView Class Reference