UILongPressGestureRecognizer无法正常工作，但将其换成UITapGestureRecognizer工作正常。为什么？ [英] UILongPressGestureRecognizer not working, but swapping it for a UITapGestureRecognizer works fine. Why?

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:

该数字手势为
识别所需的视图上的点按。

The number of taps on the view required for the gesture to be recognized.

但是在 UILongPressGestureRecognizer.h ，它说：

按下手势之前所需的全部水龙头数量
认可

The number of full taps required before the press for gesture to be recognized

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