UILongPressGestureRecognizer无法正常工作，但将其换成UITapGestureRecognizer工作正常。为什么？

问题描述

我有一个 UIImageView 附加了 UILongPressGestureRecognizer 附件，无论我怎么样，似乎都无法检测到长按手势配置手势识别器。但是，如果我换掉 UITapGestureRecognizer ，那么 就可以了。可能会发生什么？

I have a UIImageView with a UILongPressGestureRecognizer attached that never seems to detect a long press gesture no matter how I configure the gesture recognizer. However, if I swap it out for a UITapGestureRecognizer, that works just fine. What could possibly be going on?

这就是我配置 UILongPressGestureRecognizer 的方式：

UIImageView* cellView = (UIImageView*)[view viewWithTag:5];
UILongPressGestureRecognizer* longPressGestureRec =
    [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(cellLongPress:)];
longPressGestureRec.numberOfTapsRequired = 1;
longPressGestureRec.numberOfTouchesRequired = 1;
longPressGestureRec.minimumPressDuration = 0.4;
[cellView addGestureRecognizer:longPressGestureRec];
[longPressGestureRec release];

这是 cellLongPress 的样子：

-(void)cellLongPress:(UILongPressGestureRecognizer*)recognizer
{
    // This never gets called.
    NSLog(@"someone long pressed me");
}

非常简单，对吧？但是到目前为止没有运气让它运转起来。有什么想法吗？

Pretty straightforward, right? No luck so far getting it to work, though. Any ideas?

推荐答案

numberOfTapsRequired 设置为 1 这意味着用户必须在开始长按之前点击（手指向下，手指向上，手指向下0.4秒，手势识别）。

The numberOfTapsRequired is set to 1 which means the user has to tap once before starting the long press (finger down, finger up, finger down for 0.4 seconds, gesture recognized).

将 numberOfTapsRequired 更改为 0 （这是默认值）。

Change numberOfTapsRequired to 0 (which is the default).

对于该属性，文档只是说：

For that property, the documentation just says:

但是在 UILongPressGestureRecognizer.h ，它说：

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