如何向dequeueReusableCellWithReuseIdentifier返回的UICollectionViewCell子视图添加点击手势

Question

什么是有效地将敲击手势添加到UICollectionViewCell从其返回的子视图的最佳方法是什么dequeueReusableCellWithReuseIdentifier,已经附加了一堆默认手势识别器(例如a UIScrollView).我是否需要检查并查看我的一个自定义手势是否已附加(scrollView.gestureRecognizers),如果没有,则添加它？我需要我的应用程序的滚动尽可能顺利,因此检查的性能和已经创建的资源的有效重用是关键.这段代码都发生在里面cellForItemAtIndexPath.谢谢.

Answer 1

我想出了一种方法,它只需要一个共享的轻击手势识别器对象,并将设置代码从cellForItemAtIndexPath(当用户滚动时非常频繁地调用)移动到viewDidLoad(在加载视图时调用一次).这是代码:

- (void)myCollectionViewWasTapped:(UITapGestureRecognizer *)tap
{
    CGPoint tapLocation = [tap locationInView:self.collectionView];
    NSIndexPath *indexPath = [self.collectionView indexPathForItemAtPoint:tapLocation];
    if (indexPath)
    {
        MyCollectionViewCell *cell = (MyCollectionViewCell *)[self.collectionView cellForItemAtIndexPath:indexPath];
        CGRect mySubviewRectInCollectionViewCoorSys = [self.collectionView convertRect:cell.mySubview.frame fromView:cell];
        if (CGRectContainsPoint(mySubviewRectInCollectionViewCoorSys, tapLocation))
        {
            // Yay! My subview was tapped!
        }
    }
}

- (void)viewDidLoad
{
    // Invoke super
    [super viewDidLoad];

    // Add tap handler to collection view
    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(myCollectionViewWasTapped:)];
    [self.collectionView addGestureRecognizer:tap];
}