可以直接复制使用
Simulator Screen Shot - iPhone 11 Pro Max - 2019-11-07 at 11.36.50.png
import UIKit
@objc protocol LauViewFlowLayoutDelegate : NSObjectProtocol {
// 返回高度
func LausetCellNormalSize(in collectionView:UICollectionView) -> CGSize
// 返回行数
@objc optional func LauColumnCountInWaterFlowLayout(in collectionView: UICollectionView) -> Int
// 返回列间距
@objc optional func LauDefaultColumnMarginInWaterFlowLayout(in collectionView: UICollectionView) -> CGFloat
// 返回行间距
@objc optional func LauRowMarginInWaterFlowLayout(in collectionView: UICollectionView) -> CGFloat
//内边距
@objc optional func LauEdgeInsetsInWaterFlowLayout(in collectionView: UICollectionView) -> UIEdgeInsets
//组数
@objc optional func LauNumberOfSections(in collectionView: UICollectionView) -> Int
//特殊的cell在哪个Indexpath
@objc optional func LauSpecialCellIndexpath(in collectionView:UICollectionView) -> IndexPath
//特殊的cell的对应size
@objc optional func LauSpecialCellSize(in collectionView:UICollectionView, numberOfItemsInSection section: Int) -> CGSize
}
class LauLayout: UICollectionViewLayout {
weak var delegate:LauViewFlowLayoutDelegate?
/** 默认列数 */
private var DefaultColumnCount : Int = 5
private var DefaultSize:CGSize = CGSize.init(width: 50, height: 50)
private var SpecialSize:CGSize = CGSize.init(width: 50, height: 50)
private var SpecialIndex:IndexPath = IndexPath.init(item: 0, section: 0) //这个后续再支持
// 记录 collectionView 的 content 可滑动的范围
fileprivate var contentScope: CGFloat = 0
/** 每一列之间的间距 垂直 */
private var DefaultColumnMargin : CGFloat = 0.0
/** 每一行之间的间距 水平方向 */
private var DefaultRowMargin : CGFloat = 0.0
/** 边缘间距 */
private var DefaultEdgeInsets : UIEdgeInsets = UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 10)
private var LastSectionMaxHeight:CGFloat = 0
//懒加载
//存放所有cell的布局属性
fileprivate lazy var attrsArrayArray = [UICollectionViewLayoutAttributes]()
//存放所有列的当前高度
fileprivate lazy var columnHeightsAry = [CGFloat]()
// fileprivate lazy var SectionItemHeightArray: [CGFloat] = []
//第一步 ：初始化
override func prepare() {
super.prepare()
//清除高度
columnHeightsAry.removeAll()
self.contentScope = 0.0
self.getconfigData()
for _ in 0 ..< DefaultColumnCount {
columnHeightsAry.append(DefaultEdgeInsets.top)
}
//清除所有的布局属性
attrsArrayArray.removeAll()
let sections : Int = (self.collectionView?.numberOfSections)!
for num in 0 ..< sections {
let count : Int = (self.collectionView?.numberOfItems(inSection: num))!//获取分区0有多少个item
if self.delegate != nil && self.delegate?.responds(to: #selector(LauViewFlowLayoutDelegate.LauSpecialCellSize(in:numberOfItemsInSection:))) ?? false {
if let contentView = self.collectionView {
self.SpecialSize = self.delegate?.LauSpecialCellSize?(in: contentView, numberOfItemsInSection: num) ?? CGSize.init(width: self.DefaultSize.width, height: self.DefaultSize.height)
}
}
for i in 0 ..< count {
let indexpath : NSIndexPath = NSIndexPath.init(item: i, section: num)
let attrsArray = self.layoutAttributesForItem(at: indexpath as IndexPath)!
attrsArrayArray.append(attrsArray)
}
let (_, maximumInteritemHeight) = maximumInteritemForSection(heightArray: columnHeightsAry)
self.LastSectionMaxHeight = maximumInteritemHeight
columnHeightsAry.removeAll()
for _ in 0 ..< DefaultColumnCount {
columnHeightsAry.append(DefaultEdgeInsets.top)
}
}
}
/**
* 第二步 ：返回indexPath位置cell对应的布局属性
*/
override func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
let attrsArray = UICollectionViewLayoutAttributes.init(forCellWith: indexPath)
let _ItemWidth = DefaultSize.width
var _ItemHeight = DefaultSize.height
if self.SpecialSize.height != DefaultSize.height {
if let nums = self.collectionView?.numberOfItems(inSection: indexPath.section){
let mutiple = SpecialSize.height / DefaultSize.height
if indexPath.row % nums == 0 {
_ItemHeight = SpecialSize.height + DefaultRowMargin * mutiple
}else{
_ItemHeight = DefaultSize.height
}
}else{
_ItemHeight = DefaultSize.height
}
}else{
_ItemHeight = DefaultSize.height
}
let (minimumInteritemNumber, minimumInteritemHeight) = minimumInteritemForSection(heightArray: columnHeightsAry)
let itemX = DefaultEdgeInsets.left + CGFloat(minimumInteritemNumber) * (_ItemWidth + DefaultColumnMargin)
var itemY = minimumInteritemHeight
let (_, maximumInteritemHeight) = maximumInteritemForSection(heightArray: columnHeightsAry)
if indexPath.item < self.DefaultColumnCount {
itemY = itemY + self.DefaultEdgeInsets.top + LastSectionMaxHeight
}
attrsArray.frame = CGRect(x: itemX, y: itemY, width: _ItemWidth, height: CGFloat(_ItemHeight))
columnHeightsAry[minimumInteritemNumber] = attrsArray.frame.maxY
if contentScope < maximumInteritemHeight {
self.contentScope = maximumInteritemHeight
self.contentScope = contentScope + DefaultEdgeInsets.bottom
}
return attrsArray
}
//第三步 ：重写 返回所有列的高度
override var collectionViewContentSize: CGSize {
return CGSize.init(width: 0, height: self.contentScope + DefaultEdgeInsets.bottom)
}
//第四步 ：返回collection的item的frame
override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
return attrsArrayArray
}
private func getconfigData() {
guard let contentView = self.collectionView else { return }
if self.delegate != nil && (self.delegate?.responds(to: #selector(LauViewFlowLayoutDelegate.LausetCellNormalSize(in:))) ?? false) {
self.DefaultSize = self.delegate?.LausetCellNormalSize(in: contentView) ?? CGSize.init(width: 50, height: 50)
}
if self.delegate != nil && (self.delegate?.responds(to: #selector(LauViewFlowLayoutDelegate.LauRowMarginInWaterFlowLayout(in:))) ?? false){
self.DefaultColumnCount = self.delegate?.LauColumnCountInWaterFlowLayout?(in: contentView) ?? 0
}
if self.delegate != nil && (self.delegate?.responds(to: #selector(LauViewFlowLayoutDelegate.LauDefaultColumnMarginInWaterFlowLayout(in:))) ?? false) {
self.DefaultRowMargin = self.delegate?.LauDefaultColumnMarginInWaterFlowLayout?(in: contentView) ?? 0
}
if self.delegate != nil && (self.delegate?.responds(to: #selector(LauViewFlowLayoutDelegate.LauRowMarginInWaterFlowLayout(in:))) ?? false) {
self.DefaultRowMargin = self.delegate?.LauRowMarginInWaterFlowLayout?(in: contentView) ?? 0
}
if self.delegate != nil && (self.delegate?.responds(to: #selector(LauViewFlowLayoutDelegate.LauEdgeInsetsInWaterFlowLayout(in:))) ?? false) {
self.DefaultEdgeInsets = self.delegate?.LauEdgeInsetsInWaterFlowLayout?(in: contentView) ?? UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 10)
}
if self.delegate != nil && (self.delegate?.responds(to: #selector(LauViewFlowLayoutDelegate.LauSpecialCellIndexpath(in:))) ?? false ) {
self.SpecialIndex = self.delegate?.LauSpecialCellIndexpath?(in: contentView) ?? IndexPath.init(item: 0, section: 0)
}
}
/*
* 竖向布局: 计算高度最大的是哪一列 / 横向布局：计算宽度最大的是哪一行
*
* @param heightArray: 缓存 section 高度的数组 / 缓存 section 宽度的数组
* return 返回最大列的列号和高度值 / 返回最大行的行号和宽度值
*/
fileprivate func maximumInteritemForSection(heightArray: [CGFloat]) -> (Int, CGFloat) {
if heightArray.count <= 0 {
return (0, 0.0)
}
// 默认第0列的高度最小
var maximumInteritemNumber = 0
// 从缓存高度数组中取出第一个元素，作为最小的那一列的高度
var maximumInteritemHeight = heightArray[0]
// 遍历数组，查找出最小的列号和最小列的高度值
for i in 1..<heightArray.count {
let tempMaximumInteritemHeight = heightArray[i]
if maximumInteritemHeight < tempMaximumInteritemHeight {
maximumInteritemHeight = tempMaximumInteritemHeight
maximumInteritemNumber = i
}
}
return (maximumInteritemNumber, maximumInteritemHeight)
}
/*
* 竖向布局: 计算高度最小的是哪一列 / 横向布局：计算宽度最小的是哪一行
*
* @param heightArray: 缓存 section 高度的数组 / 缓存 section 宽度的数组
* return 返回最小列的列号和高度值 / 返回最小行的行号和高度值
*/
fileprivate func minimumInteritemForSection(heightArray: [CGFloat]) -> (Int, CGFloat) {
if heightArray.count <= 0 {
return (0, 0.0)
}
// 默认第0列的高度最小
var minimumInteritemNumber = 0
// 从缓存高度数组中取出第一个元素，作为最小的那一列的高度
var minimumInteritemHeight = heightArray[0]
// 遍历数组，查找出最小的列号和最小列的高度值
for i in 1..<heightArray.count {
let tempMinimumInteritemHeight = heightArray[i]
if minimumInteritemHeight > tempMinimumInteritemHeight {
minimumInteritemHeight = tempMinimumInteritemHeight
minimumInteritemNumber = i
}
}
return (minimumInteritemNumber, minimumInteritemHeight)
}
}
