ios - 双击单元格在 iOS9 上不起作用

Question

我们的项目有自定义 UICollectionViewCell，它使用 UITapGestureRecognizer 处理单击和双击，还有一个 subview 也使用单击 UITapGestureRecognizer。

这是在我们的项目中设置单击/双击的方式:

    _singleTapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleSingleTap:)];
    _singleTapGestureRecognizer.numberOfTapsRequired = 1;
    [self addGestureRecognizer:_singleTapGestureRecognizer];

    _doubleTapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleDoubleTap:)];
    _doubleTapGestureRecognizer.numberOfTapsRequired = 2;
    [self addGestureRecognizer:_doubleTapGestureRecognizer]

    [_singleTapGestureRecognizer requireGestureRecognizerToFail:_doubleTapGestureRecognizer];

在我们的代码中，我们还通过执行这些操作来取消单击/双击，

    self.singleTapGestureRecognizer.enabled = NO;

    self.doubleTapGestureRecognizer.enabled = NO;
    self.doubleTapGestureRecognizer.enabled = YES;

    self.singleTapGestureRecognizer.enabled = YES;

这些曾经在 iOS9 之前的设备上运行良好，但是最近，我发现在 iOS9 设备上，双击永远不会被触发。每次我尝试双击单元格时，它都会立即记录一次单击，几乎没有延迟。

当我试图查看它时，我发现当 singleTapGestureRecognizer 被注册时，doubleTapGestureRecognizer 仍然处于 Possible not Failed 状态。

single tap: <UITapGestureRecognizer: 0x7f94ead42220; state = Ended; view = <UIView 0x7f94ead3f710>; target= <(action=handleSingleTap:, target=<PVEntityStreamCellForSetOnboarding 0x7f94ead3f1e0>)>; must-fail = {
<UITapGestureRecognizer: 0x7f94ead42810; state = Possible; view = <UIView 0x7f94ead3f710>; target= <(action=handleDoubleTap:, target=<PVEntityStreamCellForSetOnboarding 0x7f94ead3f1e0>)>; numberOfTapsRequired = 2>
}>

我还发现，如果我先点击包含另一个 UITapGestureRecognizer 的 subview ，然后双击就会起作用，一旦我滚动 Collection View ，就不可能双击任何单元格。

有没有人有类似的问题或知道如何解决这个问题？

Answer 1

我有一个类似的问题，在我的例子中，修复是为 singleTapGestureRecognizer 实现一个委托(delegate)方法。我也尝试使用取消来单击/双击，但没有成功。现在，我的代码看起来像这样(它是用 swift 编写的，但很容易阅读):

let singleTapGestureRecognizer = UITapGestureRecognizer(target: self, action: Selector("handleSingleTap:"))
let doubleTapGestureRecognizer = UITapGestureRecognizer(target: self, action: Selector("handleDoubleTap:"))

singleTapGestureRecognizer.numberOfTapsRequired = 1
doubleTapGestureRecognizer.numberOfTapsRequired = 2

singleTapGestureRecognizer.delegate = self

singleTapGestureRecognizer.requireGestureRecognizerToFail(doubleTapGestureRecognizer)
view.addGestureRecognizer(singleTapGestureRecognizer)
view.addGestureRecognizer(doubleTapGestureRecognizer)