如何重新加载UICollectionView的数据部分? [英] How to reload only data section of UICollectionView?
问题描述
我正在尝试重新加载UICollectionView的数据部分,而不是页眉或页脚(补充视图)。
I'm trying to reload only data section, not header or footer (supplementary view), of UICollectionView.
当我使用 reloadData时
方法,页眉和页脚部分也重新加载,这就是我想要的。
When I use reloadData
method, header and footer section also reloads, so that's what I want.
我找到了方法 reloadSections:
,但我不知道为什么它不起作用。
I found the method reloadSections:
, but I don't know why it doesn't work.
因为我的集合视图只包含一个部分,所以我尝试使用该方法像这样:
Because my collection view only contains one section, so I tried using the method like this:
[collectionViewController.collectionView reloadSections:[NSIndexSet indexSetWithIndex:0]];
但调用方法时会出现运行时错误。错误的内容是:
But it makes runtime error when the method is called. The content of error is:
'NSInvalidArgumentException', reason: '-[UICollectionViewUpdateItem action]:
unrecognized selector sent to instance 0x90aec00'
方法是 reloadSections:
不允许这样使用?有没有其他方法只重新加载数据部分,而不是页眉或页脚部分?
Is the method reloadSections:
is not allowed to use like this? Is there any alternative way to reload only data section, not header or footer section?
推荐答案
我认为错误只发生在搜索栏是一个集合视图的子视图,并在键盘输入结束时尝试调用 reloadSections:
。
I think the error only occurs when the search bar is a collection view's subview, and trying to call reloadSections:
when the keyboard input is up.
< a href =https://stackoverflow.com/questions/12894172/deleting-cells-from-uicollectionview-via-nsnotification>本文给出了类似问题的答案,但这不适用于我。
This article gives an answer to a similar problem, but that didn't work for me.
所以我使用了另一种方法来调用几乎相同的功能。
So I used an alternative way with which I can invoke almost the same feature.
而不是添加标题作为补充视图,我将标题作为视图的子视图。 (不是collectionView)
Instead of adding the header as a supplementary view, I made the header a subview of 'view'. (not collectionView)
并添加了一些滚动委托来模仿表格视图的标题。
And added some scroll delegate to mimic the table view's header.
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
CGFloat y = scrollView.contentOffset.y;
if (y < 44) {
[self.searchBar setFrame:CGRectMake(0, -y, 320, 44)];
[self.searchBar setHidden:NO];
} else if (y >= 44) {
[self.searchBar setHidden:YES];
}
}
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