How to reload only data section of UICollectionView?

ios, ios6, objective-c, uicollectionview

Solution

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.

This article gives an answer to a similar problem, but that didn't work for me.

So I used an alternative way with which I can invoke almost the same feature.

Instead of adding the header as a supplementary view, I made the header a subview of 'view'. (not collectionView)

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];
    }  
}

Problem

I'm trying to reload only data section, not header or footer (supplementary view), of UICollectionView. When I use `reloadData` method, header and footer section also reloads, so that's what I want. I found the method `reloadSections:`, but I don't know why it doesn't work. Because my collection view only contains one section, so I tried using the method like this: ``` [collectionViewController.collectionView reloadSections:[NSIndexSet indexSetWithIndex:0]]; ``` 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' ``` 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?

Original source

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