UICollectionViewCell 变为隐藏=YES答案

【问题标题】：UICollectionViewCell becomes hidden=YESUICollectionViewCell 变为隐藏=YES
【发布时间】：2014-06-22 14:05:11
【问题描述】：

我正在尝试使用UICollectionView 实现“无限滚动”。

我通过像this tutorial 那样缓冲我的数据数组来做到这一点

然后通过以下方式实现UICollectionViewDelegate的didEndDisplayingCell：

- (void)collectionView:(UICollectionView *)collectionView didEndDisplayingCell:(UICollectionViewCell *)cell forItemAtIndexPath:(NSIndexPath *)indexPath{
if (self.galleryArray.count > 0) {

    NSIndexPath *newIndexPath = indexPath;

    if (self.specialHeaderView.bannerView.scrollDirection == left) {
        newIndexPath = [NSIndexPath indexPathForItem:indexPath.row - 1 inSection:indexPath.section];
    } else if (self.specialHeaderView.bannerView.scrollDirection == right) {
        newIndexPath = [NSIndexPath indexPathForItem:indexPath.row + 1 inSection:indexPath.section];
    }

    if (newIndexPath.row == (self.galleryArray.count - 1)) {
        // user is scrolling to the right from the last item to the 'fake' item 1.
        // reposition offset to show the 'real' item 1 at the left-hand end of the collection view

        newIndexPath = [NSIndexPath indexPathForItem:1 inSection:indexPath.section];

        [self.bannerCollectionView scrollToItemAtIndexPath:newIndexPath atScrollPosition:UICollectionViewScrollPositionLeft animated:NO];
        return;

    }

    //        if (scrollView.contentOffset.x == self.collectionView.frame.size.width)  {
    if (newIndexPath.row == 0) {
        // user is scrolling to the left from the first item to the fake 'item N'.
        // reposition offset to show the 'real' item N at the right end end of the collection view

        newIndexPath = [NSIndexPath indexPathForItem:([self.galleryArray count] -2) inSection:indexPath.section];

        [self.bannerCollectionView scrollToItemAtIndexPath:newIndexPath atScrollPosition:UICollectionViewScrollPositionLeft animated:NO];

    }


}

}

问题是，每当调用didEndDisplayingCell 方法并且集合视图通过其委托CellForItemAtIndexPath 方法请求一个单元格时，该单元格就会重新隐藏。

这是我的CellForItemAtIndexPath 实现：

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
SpecialBannerCell *specialBannerCell = (SpecialBannerCell *)[collectionView dequeueReusableCellWithReuseIdentifier:GalleryCellIdentifier forIndexPath:indexPath];
if (specialBannerCell.hidden) {

}
Benefit *benefit = [self.galleryArray objectAtIndex:indexPath.row];
[specialBannerCell.imageBanner setImageWithURL:[NSURL URLWithString:benefit.imageIphoneUrl] placeholderImage:[UIImage imageNamed:@"photo_loader"]];
return specialBannerCell;

}

我在这里做错了什么？

【问题讨论】：

你的单元格是隐藏在你的界面生成器还是你的xib文件中？
@LenaBru 一点也不。正如我所提到的，它确实在大多数情况下出现。无论如何，我解决了这个问题 - 解决方案发布在下面。
我在 cellforrowat 索引路径中也遇到了类似的问题，我在 Pageview 控制器中有集合视图横幅，第一次我在页面上滑动时，一切都很好，但是当我向后滑动单元格时隐藏属性为 YES。相同的代码在 iOS8 中运行良好，在 iOS9 中停止运行

标签： ios objective-c uicollectionview uicollectionviewcell uicollectionviewdelegate

【解决方案1】：

所以我不知道为什么，但是当我使用 UIScrollViewDelegate 方法而不是 didEndDisplayingCell 方法时，单元格不再隐藏并且一切正常。

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {

    if (self.galleryArray.count > 0) {

    NSIndexPath *indexPath = self.currentIndexPath;

    NSIndexPath *newIndexPath = indexPath;

    if (newIndexPath.row == (self.galleryArray.count - 1)) {
        // user is scrolling to the right from the last item to the 'fake' item 1.
        // reposition offset to show the 'real' item 1 at the left-hand end of the collection view

        newIndexPath = [NSIndexPath indexPathForItem:1 inSection:indexPath.section];

        self.currentIndexPath = newIndexPath;

        [self.bannerCollectionView scrollToItemAtIndexPath:newIndexPath atScrollPosition:UICollectionViewScrollPositionLeft animated:NO];
        return;

    }

    if (newIndexPath.row == 0) {
        // user is scrolling to the left from the first item to the fake 'item N'.
        // reposition offset to show the 'real' item N at the right end end of the collection view

        newIndexPath = [NSIndexPath indexPathForItem:([self.galleryArray count] -2) inSection:indexPath.section];

        self.currentIndexPath = newIndexPath;

        [self.bannerCollectionView scrollToItemAtIndexPath:newIndexPath atScrollPosition:UICollectionViewScrollPositionLeft animated:NO];

    }


}

}

【讨论】：