scrollView实现瀑布流

scrollView完成瀑布流：

1.根据tableView设计一个继承于scrollView的waterFlawLayoutView:

设置数据源dataSource和代理delegate方法：

 1>询问数据源要数据：

//cell的对应的数据一共有多少个

-(NSInteger)numberOfCellInWaterFlawView:(LYWaterFlawLayoutVIew *)waterFlawView;

//对应下标的cell的数据

-(LYWaterFlawVIewCell *)waterFlawView:(LYWaterFlawLayoutVIew *)waterFlawView cellAtIndex:(NSUInteger )index;

//列数

-(NSUInteger)numberOfColumnInWaterFlawView:(LYWaterFlawLayoutVIew *)waterFlawView;

 2>代理方法

注意：@protocol LYWaterFlawLayoutViewDelegate<UIScrollView>//记得要成为scrollview的代理

-(void)waterFlawView:(LYWaterFlawLayoutVIew *)waterFlawView didSelectedAtIndex:(NSInteger )index;

//每列的高度

- (CGFloat)waterflowView:(LYWaterFlawLayoutVIew  *)waterflowView heightAtIndex:(NSUInteger)index;

//间距

- (CGFloat)waterflowView:(LYWaterFlawLayoutVIew  *)waterflowView intervalForType:(LYWaterFlawLayoutVIewIntervalType)type;

//学习苹果的tableView高度是在delelgagte的，但为什么高度是放在delegate而不是在数据源方法中，why?

//接口

//刷新数据

-(void)reloadData;

//用标识符从缓冲池中换取

- (id)dequeueReusableCellWithIdentifier:(NSString *)identifier;

2.LYWaterFlawViewCell

//提供标识符

@property (nonatomic, copy) NSString *identifier;//标识符

3LYWaterFlawView

//保存每个cellde 大小位置

@property(nonatomic,strong)NSMutableArray *cellFrames;

//正在显示的cell

@property(nonatomic,strong)NSMutableDictionary *showingInScreenCell;

//cell的缓存池

@property (nonatomic, strong) NSMutableSet *reusableCells;

@implementation

//刷新重新计算所有cell的frame

-(void)reloadData {

/问数据源拿到总cell的数目

NSUInteger numberOfCells  = [self.dataSource numberOfCellInWaterFlawView:self];

//问数据源拿到总的列数

NSUInteger numberOfColumns = [self numberOfColumns];

//所有的间距

CGFloat topInterval        = [self intervalOfType:LYWaterFlawLayoutVIewIntervalTypeTop];  //上

CGFloat leftInterval      = [self intervalOfType:LYWaterFlawLayoutVIewInterValTypeLeft];  //左

CGFloat bottomInterval    = [self intervalOfType:LYWaterFlawLayoutVIewIntervalTypeBottom];//下

CGFloat rightInterval      = [self intervalOfType:LYWaterFlawLayoutVIewIntervalTypeRight]; //右

CGFloat columnInterval    = [self intervalOfType:LYWaterFlawLayoutVIewIntervalTypeColumn];//列

CGFloat rowInterval        = [self intervalOfType:LYWaterFlawLayoutVIewIntervalTypeRow];  //行

//cell的宽度

CGFloat cellWidth          = (self.width - (numberOfColumns -1)*columnInterval - leftInterval -rightInterval) / numberOfColumns;

//C的数组用于保存每列的当前的高度

CGFloat maxY[numberOfColumns];

for (int i = 0 ; i < numberOfColumns; i++) {

maxY[i] = 0.0;

}

}

for (int i = 0 ; i < numberOfCells; i++)

 {        NSUInteger minCellColumn = 0;//记录最小Y的那列        CGFloat minYOfColumns = maxY[minCellColumn];//设最小那列的y值                for (int j = 1; jcontentY) {

contentY = maxY[i];

}