iOS UICollectionViewCells Layout with intersection

Question

I try to make UICollectionView with cells, that intersect and partially overlay each other as it is done at screenshot: This layout was reached by setting

self.minimumLineSpacing = -100;

at my UICollectionViewFlowLayout subclass. When I scroll down, everything is OK. I see what I want. But when I scroll up, I see another behaviour, not like I expected: So my question is: how can I make my layout look as at the first screen regardless scroll view direction. Note: I have to support both iOS 6 and 7.

Thanks very much for any advices and any help.

Answer 1

Found another sollution to solve this problem. We need to use UICollectionViewFlowLayout subclass.

@interface MyFlowLayout : UICollectionViewFlowLayout
@end

@implementation MyFlowLayout

- (void)prepareLayout {
    [super prepareLayout];
    // This allows us to make intersection and overlapping
    self.minimumLineSpacing = -100;
}

- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect
{
    NSArray *layoutAttributes = [super layoutAttributesForElementsInRect:rect];
    for (UICollectionViewLayoutAttributes *currentLayoutAttributes in layoutAttributes) {
        // Change zIndex allows us to change not only visible position, but logic too
        currentLayoutAttributes.zIndex = currentLayoutAttributes.indexPath.row;
    }
    return layoutAttributes;
}

@end

Hope that helps someone else.