UICollectionView: How to get the header view for a section?

Question

There is a method to get a cell by indexPath (UICollectionView cellForItemAtIndexPath:). But I can\"t find a method to get one of the supplementary vie

Answer 1

I would like to share my insight of the solution provided by rob mayoff but I can't post comment so I am putting it here:

For every one of you that tried to keep reference of the supplementary views being used by a collection view but who run into issues of loosing track too early because of

collectionView:didEndDisplayingSupplementaryView:forElementOfKind:atIndexPath:

being called too many times, try using an NSMapTable instead of a dictionary.

I use

@property (nonatomic, strong, readonly) NSMapTable *visibleCollectionReusableHeaderViews;

created like this:

_visibleCollectionReusableHeaderViews = [NSMapTable mapTableWithKeyOptions:NSMapTableStrongMemory valueOptions:NSMapTableWeakMemory];

so that when you are keeping a reference to a supplementary view:

- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
{
    // ( ... )
    [_visibleCollectionReusableHeaderViews setObject:cell forKey:indexPath];

it keeps only a WEAK reference to it in the NSMapTable and it keeps it AS LONG AS the object is not deallocated!

You don't need anymore to remove the view from

collectionView:didEndDisplayingSupplementaryView:forElementOfKind:atIndexPath:

as the NSMapTable will lose the entry as soon as the view is deallocated.