问定制uicollectionview布局编码

EN

var preferredSize: CGSize? = CGSize(width: 100, height: 100)


override func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
    let attributes = UICollectionViewLayoutAttributes(forCellWith: indexPath)

    attributes.size = preferredSize!
//Modifying the centerX property adjust the overlapping effect
    let centerX = (preferredSize?.width)! / 2.0 + CGFloat(indexPath.item) * ((preferredSize?.width)! * 0.5 )
    let centerY = collectionView!.bounds.height / 2.0
    attributes.center = CGPoint(x: centerX, y: centerY)
    attributes.zIndex = -(indexPath.item)

    return attributes
}