对 UIScrollview 的子视图使用 UILongPressGestureRecognizer

问题描述

在过去的四个小时里，我尝试了许多 Stack Overlow 解决方案，但都没有解决我的问题.

来了，

• 我有一个 UIScrollView
• 在该 ScrollView 中有 一个自定义 UILabel 和 8 个自定义 UIImageViews
• 我想检测长按

• 类似这样的方法

  UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressDidFire:)];
longPress.minimumPressDuration = 0.5;[滚动添加手势识别器:长按]；//滚动在别处定义

但是，如果我将滚动替换为滚动的任何子视图，则长按事件永远不会触发.

1. 如何检测长按滚动视图的子视图?
2. 这是一个相当混乱的 hack，但是，因为我可以检测到滚动视图的长按，有什么方法可以检测到印刷机的位置，以便我可以看到哪个特定的子视图被按下.

另外，(insert subview here).userInteractionEnabled = YES，我为滚动视图的所有子视图设置了这个属性，所以这应该不是问题.

我也尝试过使用 Stack Overflow 中其他地方建议的 touchesBegan 和 touchesEnded 方法.

此外，对于图像视图，我确实使用 for 循环为每个自定义图像视图设置了一个新的 UILongPressGestureRecognizer，因为我知道每个手势识别器 1 个视图规则.

来自第一次 iOS 开发者，

格雷厄姆

附:如果我能找到 1. 而不是凌乱的 2. 的解决方案，我真的更喜欢.

应要求提供更多代码:

在视图控制器的初始化中

 UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressDidFire:)];longPress.minimumPressDuration = 0.5;[self.titleLabel addGestureRecognizer:longPress];//titleLabel 属性在别处初始化[mainView addSubview:self.titleLabel];

在加载图像"方法中

for (NSData * dataImg in results) {//做一些工作将数据转换为图像，转换为名为 img 的图像视图img.delegate = 自我；img.userInteractionEnabled = YES；UILongPressGestureRecognizer *aLongPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressDidFire:)];aLongPress.minimumPressDuration = 0.5;[img addGestureRecognizer:aLongPress];[imgContainer addSubview:img];}

<小时>

更多代码 + 注释

self.view (UIView)

->滚动(UIScrollView)

->->主视图(UIView)

->->->titleLabel(UILabel)

->->->imgContainer (UIView)

->->->->图像(UIImageViews)

[self.view addSubview:scroll];[滚动添加子视图:主视图]；[mainView addSubview:self.titleLabel];[主视图添加子视图:imgContainer]；[imgContainer addSubview:img];//通过for循环完成8x

感谢@RegularExpression 的回答，我现在知道 mainView 被按下了，但不是它的子视图，所以我需要找到一种方法来在它上面显示 mainView 的子视图.:)

另一个更新，titleLabel 有效.ImageViews 仍然不起作用.:(

哇哦！

问题是:

imgContainer 是一个 带有空框架的 UIView，其中有几个 UIImageViews 作为子视图

我的印象是，当我向 imgContainer 添加子视图时，imgContainer 会展开.

这不是真的.

我必须将 imgContainer 的框架设置为与滚动视图相同的内容框架，然后一切正常.

我希望这个答案可以帮助像我这样的任何其他未来的 iOS 初学者.

For the past four hours, I have tried many Stack Overlow solutions but none have helped solve my problem.

Here it is,

• I have a UIScrollView
• Within that ScrollView there is one custom UILabel and 8 custom UIImageViews
• I want to detect a long press

• Something like this works

  UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressDidFire:)];
longPress.minimumPressDuration = 0.5; [scroll addGestureRecognizer:longPress]; //scroll defined elsewhere

However, if I replace the scroll with any subviews of scroll, the long press event never fires.

1. How do I detect a long press of a subview of a scroll view?
2. This is quite a messy hack, however, since I can detect long presses of a scroll view, is there any way where I can detect the position of the press so that I can see which specific subview is being pressed.

Also, (insert subview here).userInteractionEnabled = YES, I set this property for all my subviews of the scroll view, so this should not be a problem.

I have also tried using touchesBegan and touchesEnded method as suggested elsewhere in Stack Overflow.

Also, for the image views, I do set a new UILongPressGestureRecognizer for every custom image view, using a for loop, as I am aware of the 1 view per gesture recognizer rule.

From A First Time iOS Developer,

Graham

P.S. I'd really prefer if I could find a solution for 1. rather than the messy 2.

More Code As Requested:

In the Init of the view Controller

 UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressDidFire:)];
longPress.minimumPressDuration = 0.5;
[self.titleLabel addGestureRecognizer:longPress]; //titleLabel property initialized elsewhere
[mainView addSubview:self.titleLabel];

In a "load images" method

for (NSData * dataImg in results) {
//Does some work turning data into an image, into an image view called img
        img.delegate = self;
        img.userInteractionEnabled = YES;
        UILongPressGestureRecognizer *aLongPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressDidFire:)];
        aLongPress.minimumPressDuration = 0.5;
        [img addGestureRecognizer:aLongPress];
        [imgContainer addSubview:img];
}

Even More Code + Notes

self.view (UIView)

->scroll (UIScrollView)

->->mainView (UIView)

->->->titleLabel (UILabel)

->->->imgContainer (UIView)

->->->->images (UIImageViews)

[self.view addSubview:scroll];
[scroll addSubview:mainView];
[mainView addSubview:self.titleLabel];
[mainView addSubview:imgContainer];
[imgContainer addSubview:img]; //done 8x via for loop

Thanks to @RegularExpression's answer, I now am aware that the mainView is getting pressed, but not its subviews, so I need to find a way to display the mainView's subviews above it. :)

Another update, titleLabel works. ImageViews still don't work though. :(

Woohoo it works!

The problem was:

imgContainer was a UIView with an empty frame with several UIImageViews as subviews

I was under the impression that as I added a subview to imgContainer, imgContainer would expand.

This is not true.

I had to set imgContainer's frame to the same content frame as the scroll view and then everything became ok.

I hope this answer helps any other future iOS firs timers like me.

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