CollectionView 实现瀑布流布局

核心代码：FlowLayout

使用方法

导入文件 FlowLayout

#import "SIWaterFlowLayout.h"

设置为相应布局

SIWaterFlowLayout *flowLayout = [[SIWaterFlowLayout alloc]init] ;
self.collectionView.collectionViewLayout = flowLayout ;

设置布局基本属性

flowLayout.itemSpace = 10 ;  // 水平间距
flowLayout.lineSpace = 10 ;   // 垂直间距
flowLayout.colCount = 3 ;   // 列数
flowLayout.sectionInset = UIEdgeInsetsMake(10, 10, 10, 10) ;  // 组间距

设置代理

flowLayout.delegate = self ;

实现代理方法

#pragma mark -SIWaterFlowLayoutDelegate

// 获取item的高度
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(SIWaterFlowLayout  *)waterFlowLayout heightForWidth:(CGFloat)width atIndexPath:(NSIndexPath *)indexPath{
    DataModel *mo = _dataArray[indexPath.section][indexPath.item] ;
    return mo.h / mo.w *width + bottomHeight ;
}

// 获取Fooder的Size
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(SIWaterFlowLayout   *)waterFlowLayout referenceSizeForFooterInSection:(NSInteger)section{
    return CGSizeMake(self.view.frame.size.width - 20, 40);
}

// 获取Header的Size
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(SIWaterFlowLayout   *)waterFlowLayout referenceSizeForHeaderInSection:(NSInteger)section{
    return CGSizeMake(self.view.frame.size.width - 20, 40);
}