How to make Supplementary View float in UICollectionView as Section Headers do in UITableView plain style

Question

I\'m struggling to achieve a \"floating section header\" effect with UICollectionView. Something that\'s been easy enough in UITableView (default b

Answer 1

I ran into the same problem and found this in my google results. First I would like to thank cocotutch for sharing his solution. However, I wanted my UICollectionView to scroll horizontally and the headers to stick to the left of the screen, so I had to change the solution a bit.

Basically I just changed this:

        CGFloat headerHeight = CGRectGetHeight(layoutAttributes.frame);
        CGPoint origin = layoutAttributes.frame.origin;
        origin.y = MIN(
                       MAX(
                           contentOffset.y,
                           (CGRectGetMinY(firstCellAttrs.frame) - headerHeight)
                           ),
                       (CGRectGetMaxY(lastCellAttrs.frame) - headerHeight)
                       );

        layoutAttributes.zIndex = 1024;
        layoutAttributes.frame = (CGRect){
            .origin = origin,
            .size = layoutAttributes.frame.size
        };

to this:

        if (self.scrollDirection == UICollectionViewScrollDirectionVertical) {
            CGFloat headerHeight = CGRectGetHeight(layoutAttributes.frame);
            CGPoint origin = layoutAttributes.frame.origin;
            origin.y = MIN(
                           MAX(contentOffset.y, (CGRectGetMinY(firstCellAttrs.frame) - headerHeight)),
                           (CGRectGetMaxY(lastCellAttrs.frame) - headerHeight)
                           );

            layoutAttributes.zIndex = 1024;
            layoutAttributes.frame = (CGRect){
                .origin = origin,
                .size = layoutAttributes.frame.size
            };
        } else {
            CGFloat headerWidth = CGRectGetWidth(layoutAttributes.frame);
            CGPoint origin = layoutAttributes.frame.origin;
            origin.x = MIN(
                           MAX(contentOffset.x, (CGRectGetMinX(firstCellAttrs.frame) - headerWidth)),
                           (CGRectGetMaxX(lastCellAttrs.frame) - headerWidth)
                           );

            layoutAttributes.zIndex = 1024;
            layoutAttributes.frame = (CGRect){
                .origin = origin,
                .size = layoutAttributes.frame.size
            };
        }

See: https://gist.github.com/vigorouscoding/5155703 or http://www.vigorouscoding.com/2013/03/uicollectionview-with-sticky-headers/