Example of how to create a pinned header with UICollectionView (i.e., a header that doesn't scroll with the rest of the cells). As simple as possible - assumes a single header, at index path [0,0], to be pinned at the top of the collection view.

gistfile1.m

//Override UICollectionViewFlowLayout class
@interface FixedHeaderLayout : UICollectionViewFlowLayout
@end

@implementation FixedHeaderLayout
//Override shouldInvalidateLayoutForBoundsChange to require a layout update when we scroll 
- (BOOL) shouldInvalidateLayoutForBoundsChange:(CGRect)newBounds {
    return YES;
}

//Override layoutAttributesForElementsInRect to provide layout attributes with a fixed origin for the header
- (NSArray *) layoutAttributesForElementsInRect:(CGRect)rect {

    NSMutableArray *result = [[super layoutAttributesForElementsInRect:rect] mutableCopy];

    //see if there's already a header attributes object in the results; if so, remove it
    NSArray *attrKinds = [result valueForKeyPath:@"representedElementKind"];
    NSUInteger headerIndex = [attrKinds indexOfObject:UICollectionElementKindSectionHeader];
    if (headerIndex != NSNotFound) {
        [result removeObjectAtIndex:headerIndex];
    }

    CGPoint const contentOffset = self.collectionView.contentOffset;
    CGSize headerSize = self.headerReferenceSize;
    
    //create new layout attributes for header
    UICollectionViewLayoutAttributes *newHeaderAttributes = [UICollectionViewLayoutAttributes layoutAttributesForSupplementaryViewOfKind:UICollectionElementKindSectionHeader withIndexPath:[NSIndexPath indexPathForItem:0 inSection:0]];
    CGRect frame = CGRectMake(0, contentOffset.y, headerSize.width, headerSize.height);  //offset y by the amount scrolled
    newHeaderAttributes.frame = frame;
    newHeaderAttributes.zIndex = 1024;
    
    [result addObject:newHeaderAttributes];

    return result;
}
@end

By using this sample, the header does be sticky as wished, thanks. But here is another issue involved: if some UIControl like button is also in header view, they can be interacted by touching correctly with this sample...

simplelife-patrick, is this true or did u figure out u were doing it wrong?

Thank you for sharing this method =)

To work this code I needed to add headerReferenceSize like this:

self.headerReferenceSize = CGSizeMake(200, 60);

Otherwise for me it was not appearing header.

Thanks for the code! ;)

Didn't knew I had to put layoutAttributesForSupplementaryViewOfKind inside the call of layoutAttributesForElementsInRect:(CGRect)rect.

This has been a lot of help. Thanks!