如何在iPhone WWDC 2010 - 104 PhotoScroller中双击放大/缩小照片 [英] How to Zoom In/Out Photo on double Tap in the iPhone WWDC 2010 - 104 PhotoScroller

问题描述

我正在浏览iPhone WWDC 2010 - 104 PhotoScroller App的示例代码。
它与我的项目相关图像（PDF页面图像）工作得很好

I am going through the Sample code of iPhone WWDC 2010 - 104 PhotoScroller App. It's working great with my project related images (PDF Page Images)

但我正在努力检测PhotoScroller应用程序中的触摸。使用多个触摸的缩放由ScrollVoiew处理。现在我想要双击放大/缩小照片。在TilingView类中调用Touchesbegan方法。然后我用[super touchesbegan：withevent：]现在接触到了ImageScrollView类。

but I am struggling detect touches in the PhotoScroller App. The Zooming using multiple touches is handled by the ScrollVoiew. Now I want to Zoom In/out the photo on double Tap. The Touchesbegan method is being called in TilingView Class. Then I used [super touchesbegan: withevent:] and now the touches are in the ImageScrollView Class.

如何在PhotoViewController中获取这些触摸事件。
如何实现放大和缩小触摸？

How to get these touch events in PhotoViewController. How to achieve the zoom in and zoom out on touch ?

任何人都可以在这方面提供帮助？

Can anyone help in this Regard ?

推荐答案

我研究了几个不同的网站，我想出了以下...

I researched several different web sites and I came up with the following...

这段代码放入您的viewDidLoad或viewWillAppear中的方法：

Place this code into your viewDidLoad or viewWillAppear method:

//////////////////////////////
// Listen for Double Tap Zoom

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

[doubleTap setNumberOfTapsRequired:2];

[self.scrollView addGestureRecognizer:doubleTap];

[doubleTap release];

将此添加到您的头文件中：

Add this to your header file:

- (void)handleDoubleTap:(UIGestureRecognizer *)gestureRecognizer;

将此添加到您的实施中：

Add this to your implementation:

- (void)handleDoubleTap:(UIGestureRecognizer *)gestureRecognizer {  

    if(self.scrollView.zoomScale > self.scrollView.minimumZoomScale)
        [self.scrollView setZoomScale:self.scrollView.minimumZoomScale animated:YES]; 
    else 
        [self.scrollView setZoomScale:self.scrollView.maximumZoomScale animated:YES]; 

  }  

目前这不是以用户双倍的区域为中心点击。

Currently this does not center upon the area where the user double tapped.

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