如何在UICollectionView中检测单元格上的双击 [英] How to detect double-taps on cells in a UICollectionView

问题描述

我想对UICollectionView中的单元格进行双击，并选择双击动作取消单元格。

I want to respond to double-taps on cells in a UICollectionView, and have a double-tap action cancel cell selection.

这就是我试过的：

UITapGestureRecognizer *tapRecogniser = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTapGesture:)];
tapRecogniser.numberOfTapsRequired = 2;

 for (UITapGestureRecognizer *recogniser in [self.collectionView gestureRecognizers]) {
    [recogniser requireGestureRecognizerToFail:tapRecogniser];
}

[self.collectionView addGestureRecognizer:tapRecogniser];

也就是说，如果我的双击手势识别器，我试图让默认手势识别器失败成功。

That is, I am trying to get the default gesture recognisers to fail if my double-tap gesture recogniser succeeds.

这似乎不起作用，因为我的集合视图委托的 collectionView：didSelectItemAtIndexPath：仍在获得双击后调用

This doesn't appear to work, as my collection view delegate's collectionView:didSelectItemAtIndexPath: is still getting called after a double-tap

Apple的文档在这一点上具有误导性，声称默认手势识别器是UITapGestureRecognizer子类的一个实例，因此可以使用 [recogniser isKindOfClass：[UITapGestureRecognizer class]]轻松选择它。 。不幸的是这是一个错误。

Apple's documentation is misleading on this point, claiming that the default gesture recogniser is an instance of a UITapGestureRecognizer subclass, so it can be easily picked out with [recogniser isKindOfClass:[UITapGestureRecognizer class]]. Unfortunately this is an error.

推荐答案

我不明白你为什么需要requireToFail。我在UICollectionView中使用双击并且它不会干扰我的单击（用于选择）。

I don't see why you need the requireToFail. I use double-taps in a UICollectionView and it doesn't interfere with my single taps (used for selection).

我使用以下内容：

UITapGestureRecognizer *doubleTapFolderGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(processDoubleTap:)];
[doubleTapFolderGesture setNumberOfTapsRequired:2];
[doubleTapFolderGesture setNumberOfTouchesRequired:1];
[self.view addGestureRecognizer:doubleTapFolderGesture];

然后，这个：

- (void) processDoubleTap:(UITapGestureRecognizer *)sender
{
    if (sender.state == UIGestureRecognizerStateEnded)
    {
        CGPoint point = [sender locationInView:collectionView];
        NSIndexPath *indexPath = [collectionView indexPathForItemAtPoint:point];
        if (indexPath)
        {
            NSLog(@"Image was double tapped");
        }
        else 
        {
            DoSomeOtherStuffHereThatIsntRelated;
        }
    }
}

似乎工作正常 - 双击被识别，我可以按照自己的意愿处理它（在这种情况下，我正在扩展文件夹的内容）。但单击会导致选择抽头销售，我没有写任何手势识别。

Seems to working fine -- the double tap is recognized and I can handle it as I wish (in this case I'm expanding the contents of a folder). But a single-tap will cause the tapped sell to be selected, which I haven't written any gesture recognition for.

重要编辑：

我正在重新审视这个问题，因为我已经看到我的原始答案在某些情况下可能是错误的，并且有一个明显的解决方案似乎有效。

需要添加以下行：

doubleTapFolderGesture.delaysTouchesBegan = YES;

消除了单击选择电池的干扰。这提供了更强大的设置。

which eliminates interference with the single tap for cell selection. This provides a much more robust setup.

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