objective-c - UIGestureRecognizers 冲突

Question

我有一个重写的 UIGestureRecogniser 设计用于检测 2 次触摸，但不一定是一个接一个地检测。

我有:

- (BOOL)canBePreventedByGestureRecognizer:(UIGestureRecognizer *)preventingGestureRecognizer
{
    if ([preventingGestureRecognizer isKindOfClass:[UIRotationGestureRecognizer class]])
    {
        self.state = UIGestureRecognizerStateCancelled;
        return YES;
    }

    if ([preventingGestureRecognizer isKindOfClass:[UISwipeGestureRecognizer class]])
    {
        self.state = UIGestureRecognizerStateCancelled;
        return YES;
    }

    //Will prevent a conflict with a 2 finger touch only.   
    if ([preventingGestureRecognizer isKindOfClass:[UITapGestureRecognizer class]])
    {
        if (preventingGestureRecognizer.numberOfTouches == 2)
        {
            self.state = UIGestureRecognizerStateCancelled;
            return YES;
        }  
        return NO;
    }
    self.state = UIGestureRecognizerStateRecognized;
    return NO;
}

在我的 MVC 中，我还有一个旋转手势识别器。我的问题是它们相互矛盾。我的 doubleTap 手势识别器正在调用它的 Action @selector 当它应该被上面的方法阻止时。

看起来上面的方法没有被调用。我认为这是因为当两根手指接触执行旋转时有以下代码:

- (void)secondTouchRecived
{
    self.state = UIGestureRecognizerStateRecognized;
}

调用 UIGestureResponders 操作方法并绕过预防方法。我尝试将其更改为 UIGestureRecogniserStateBegan 但这似乎也绕过了预防方法。

Answer 1

如何通过将旋转、滑动和点击手势识别器传递到 requireGestureRecognizerToFail: 在您的自定义手势识别器上来指定依赖项？这将阻止您的手势识别器在旋转识别器有机会处理触摸之前转换到 Recognized 状态。