当数据源只有1个项目时，UICollectionView不会反弹 [英] UICollectionView doesn't bounce when datasource has only 1 item

问题描述

我有一个带有自定义UICollectionViewFlowLayout的UICollectionView。它水平滚动，一次只显示一个项目（全高）。我有pagingEnabled = YES，所以它坚持页面。

I have a UICollectionView with a custom UICollectionViewFlowLayout. It scrolls horizontally and only shows one item at a time (full height). I have pagingEnabled = YES so that it sticks to pages.

UICollectionView显示特定日期内的照片。我最初有按钮来改变日+/- 1天，但我认为如果用户可以通过第一张或最后一张图像（超过预定阈值）拉动收集视图以改变日期，那将是整洁的。我使用UIScrollView委托方法实现了它，如果集合视图中有2个或更多项，它可以很好地工作。

The UICollectionView shows photos within a particular day. I initially had buttons to change the day +/- 1 day, but I thought it would be neat if the user could pull on the collection view past the first or last image (past a predetermined threshold) to change the day. I implemented this using the UIScrollView delegate methods and it works great...... if there are 2 or more items in the collection view.

这很难描述，但如果只有一个项目，则不允许我拉出项目超出界限。 I.E.它没有反弹。

This is hard to describe, but if there is only 1 item, it doesn't allow me to pull the item past it's bounds. I.E. there is no bounce to it.

我想有这种行为，但我需要先解决这个问题。我想如果我删除了pagingEnabled = YES并使用了targetContentOffsetForProposedContentOffset：proposedContentOffset：withScrollingVelocity，那我可以让它工作但我真的很喜欢分页启用的快速行为。 （它们是相互排斥的）。

I'd like to have this behavior, but I need to overcome this problem first. I'm thinking that if I removed pagingEnabled = YES and used targetContentOffsetForProposedContentOffset:proposedContentOffset:withScrollingVelocity, that I may be able to get it to work but I really enjoy the snappy behavior that paging enables. (They are mutually exclusive).

有关于此的任何想法吗？

Any ideas on this?

推荐答案

UICollectionView 具有 alwaysBounceHorizo​​ntal 和 alwaysBounceVertical 属性。将水平设置为YES 确实。

UICollectionView has the properties alwaysBounceHorizontal and alwaysBounceVertical. Setting the horizontal to YES did the trick.

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