可以使用获得该效果
UICollectionView。这里是
UICollectionViewFlowLayout类。
class UltravisualLayout: UICollectionViewLayout { private var contentWidth:CGFloat! private var contentHeight:CGFloat! private var yOffset:CGFloat = 0 var maxAlpha:CGFloat = 1 var minAlpha:CGFloat = 0 var widthOffset:CGFloat = 35 var heightOffset:CGFloat = 35 private var cache = [UICollectionViewLayoutAttributes]() private var itemWidth:CGFloat{ return (collectionView?.bounds.width)! } private var itemHeight:CGFloat{ return (collectionView?.bounds.height)! } private var collectionViewHeight:CGFloat{ return (collectionView?.bounds.height)! } private var numberOfItems:Int{ return (collectionView?.numberOfItemsInSection(0))! } private var dragOffset:CGFloat{ return (collectionView?.bounds.height)! } private var currentItemIndex:Int{ return max(0, Int(collectionView!.contentOffset.y / collectionViewHeight)) } var nextItemBecomeCurrentPercentage:CGFloat{ return (collectionView!.contentOffset.y / (collectionViewHeight)) - CGFloat(currentItemIndex) } override func prepareLayout() { cache.removeAll(keepCapacity: false) yOffset = 0 for item in 0 ..< numberOfItems{ let indexPath = NSIndexPath(forItem: item, inSection: 0) let attribute = UICollectionViewLayoutAttributes(forCellWithIndexPath: indexPath) attribute.zIndex = -indexPath.row if (indexPath.item == currentItemIndex+1) && (indexPath.item < numberOfItems){ attribute.alpha = minAlpha + max((maxAlpha-minAlpha) * nextItemBecomeCurrentPercentage, 0) let width = itemWidth - widthOffset + (widthOffset * nextItemBecomeCurrentPercentage) let height = itemHeight - heightOffset + (heightOffset * nextItemBecomeCurrentPercentage) let deltaWidth = width/itemWidth let deltaHeight = height/itemHeight attribute.frame = CGRectMake(0, yOffset, itemWidth, itemHeight) attribute.transform = CGAffineTransformMakeScale(deltaWidth, deltaHeight) attribute.center.y = (collectionView?.center.y)! + (collectionView?.contentOffset.y)! attribute.center.x = (collectionView?.center.x)! + (collectionView?.contentOffset.x)! yOffset += collectionViewHeight }else{ attribute.frame = CGRectMake(0, yOffset, itemWidth, itemHeight) attribute.center.y = (collectionView?.center.y)! + yOffset attribute.center.x = (collectionView?.center.x)! yOffset += collectionViewHeight } cache.append(attribute) } } //Return the size of ContentView override func collectionViewContentSize() -> CGSize { contentWidth = (collectionView?.bounds.width)! contentHeight = CGFloat(numberOfItems) * (collectionView?.bounds.height)! return CGSizeMake(contentWidth, contentHeight) } //Return Attributes whose frame lies in the Visible Rect override func layoutAttributesForElementsInRect(rect: CGRect) -> [UICollectionViewLayoutAttributes]? { var layoutAttributes = [UICollectionViewLayoutAttributes]() for attribute in cache{ if CGRectIntersectsRect(attribute.frame, rect){ layoutAttributes.append(attribute) } } return layoutAttributes } override func shouldInvalidateLayoutForBoundsChange(newBounds: CGRect) -> Bool { return true } override func targetContentOffsetForProposedContentOffset(proposedContentOffset: CGPoint, withScrollingVelocity velocity: CGPoint) -> CGPoint { let itemIndex = round(proposedContentOffset.y / (dragOffset)) let yOffset = itemIndex * (collectionView?.bounds.height)! return CGPoint(x: 0, y: yOffset) } override func layoutAttributesForItemAtIndexPath(indexPath: NSIndexPath) -> UICollectionViewLayoutAttributes? { // Logic that calculates the UICollectionViewLayoutAttributes of the item // and returns the UICollectionViewLayoutAttributes return UICollectionViewLayoutAttributes(forCellWithIndexPath: indexPath) }}这是演示项目链接 …
非常感谢本 教程。
