李老师写的框架，学习学习。
#import <UIKit/UIKit.h>
@class XMGWaterflowLayout;
@protocol XMGWaterflowLayoutDelegate <NSObject>
@required
- (CGFloat)waterflowLayout:(XMGWaterflowLayout *)waterflowLayout heightForItemAtIndex:(NSUInteger)index itemWidth:(CGFloat)itemWidth;
@optional
- (CGFloat)columnCountInWaterflowLayout:(XMGWaterflowLayout *)waterflowLayout;
- (CGFloat)columnMarginInWaterflowLayout:(XMGWaterflowLayout *)waterflowLayout;
- (CGFloat)rowMarginInWaterflowLayout:(XMGWaterflowLayout *)waterflowLayout;
- (UIEdgeInsets)edgeInsetsInWaterflowLayout:(XMGWaterflowLayout *)waterflowLayout;
@end
@interface XMGWaterflowLayout : UICollectionViewLayout
/** 代理 */
@property (nonatomic, weak) id<XMGWaterflowLayoutDelegate> delegate;
@end
#import "XMGWaterflowLayout.h"
/** 默认的列数 */
static const NSInteger XMGDefaultColumnCount = 3;
/** 每一列之间的间距 */
static const CGFloat XMGDefaultColumnMargin = 10;
/** 每一行之间的间距 */
static const CGFloat XMGDefaultRowMargin = 10;
/** 边缘间距 */
static const UIEdgeInsets XMGDefaultEdgeInsets = {10, 10, 10, 10};
@interface XMGWaterflowLayout()
/** 存放所有cell的布局属性 */
@property (nonatomic, strong) NSMutableArray *attrsArray;
/** 存放所有列的当前高度 */
@property (nonatomic, strong) NSMutableArray *columnHeights;
/** 内容的高度 */
@property (nonatomic, assign) CGFloat contentHeight;
- (CGFloat)rowMargin;
- (CGFloat)columnMargin;
- (NSInteger)columnCount;
- (UIEdgeInsets)edgeInsets;
@end
@implementation XMGWaterflowLayout
#pragma mark - 常见数据处理
- (CGFloat)rowMargin
{
if ([self.delegate respondsToSelector:@selector(rowMarginInWaterflowLayout:)]) {
return [self.delegate rowMarginInWaterflowLayout:self];
} else {
return XMGDefaultRowMargin;
}
}
- (CGFloat)columnMargin
{
if ([self.delegate respondsToSelector:@selector(columnMarginInWaterflowLayout:)]) {
return [self.delegate columnMarginInWaterflowLayout:self];
} else {
return XMGDefaultColumnMargin;
}
}
- (NSInteger)columnCount
{
if ([self.delegate respondsToSelector:@selector(columnCountInWaterflowLayout:)]) {
return [self.delegate columnCountInWaterflowLayout:self];
} else {
return XMGDefaultColumnCount;
}
}
- (UIEdgeInsets)edgeInsets
{
if ([self.delegate respondsToSelector:@selector(edgeInsetsInWaterflowLayout:)]) {
return [self.delegate edgeInsetsInWaterflowLayout:self];
} else {
return XMGDefaultEdgeInsets;
}
}
#pragma mark - 懒加载
- (NSMutableArray *)columnHeights
{
if (!_columnHeights) {
_columnHeights = [NSMutableArray array];
}
return _columnHeights;
}
- (NSMutableArray *)attrsArray
{
if (!_attrsArray) {
_attrsArray = [NSMutableArray array];
}
return _attrsArray;
}
/**
* 初始化
*/
- (void)prepareLayout
{
[super prepareLayout];
self.contentHeight = 0;
// 清除以前计算的所有高度
[self.columnHeights removeAllObjects];
for (NSInteger i = 0; i < self.columnCount; i++) {
[self.columnHeights addObject:@(self.edgeInsets.top)];
}
// 清除之前所有的布局属性
[self.attrsArray removeAllObjects];
// 开始创建每一个cell对应的布局属性
NSInteger count = [self.collectionView numberOfItemsInSection:0];
for (NSInteger i = 0; i < count; i++) {
// 创建位置
NSIndexPath *indexPath = [NSIndexPath indexPathForItem:i inSection:0];
// 获取indexPath位置cell对应的布局属性
UICollectionViewLayoutAttributes *attrs = [self layoutAttributesForItemAtIndexPath:indexPath];
[self.attrsArray addObject:attrs];
}
}
/**
* 决定cell的排布
*/
- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect
{
return self.attrsArray;
}
/**
* 返回indexPath位置cell对应的布局属性
*/
- (UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath
{
// 创建布局属性
UICollectionViewLayoutAttributes *attrs = [UICollectionViewLayoutAttributes layoutAttributesForCellWithIndexPath:indexPath];
// collectionView的宽度
CGFloat collectionViewW = self.collectionView.frame.size.width;
// 设置布局属性的frame
CGFloat w = (collectionViewW - self.edgeInsets.left - self.edgeInsets.right - (self.columnCount - 1) * self.columnMargin) / self.columnCount;
CGFloat h = [self.delegate waterflowLayout:self heightForItemAtIndex:indexPath.item itemWidth:w];
// 找出高度最短的那一列
NSInteger destColumn = 0;
CGFloat minColumnHeight = [self.columnHeights[0] doubleValue];
for (NSInteger i = 1; i < self.columnCount; i++) {
// 取得第i列的高度
CGFloat columnHeight = [self.columnHeights[i] doubleValue];
if (minColumnHeight > columnHeight) {
minColumnHeight = columnHeight;
destColumn = i;
}
}
CGFloat x = self.edgeInsets.left + destColumn * (w + self.columnMargin);
CGFloat y = minColumnHeight;
if (y != self.edgeInsets.top) {
y += self.rowMargin;
}
attrs.frame = CGRectMake(x, y, w, h);
// 更新最短那列的高度
self.columnHeights[destColumn] = @(CGRectGetMaxY(attrs.frame));
// 记录内容的高度
CGFloat columnHeight = [self.columnHeights[destColumn] doubleValue];
if (self.contentHeight < columnHeight) {
self.contentHeight = columnHeight;
}
return attrs;
}
- (CGSize)collectionViewContentSize
{
// CGFloat maxColumnHeight = [self.columnHeights[0] doubleValue];
// for (NSInteger i = 1; i < self.columnCount; i++) {
// // 取得第i列的高度
// CGFloat columnHeight = [self.columnHeights[i] doubleValue];
//
// if (maxColumnHeight < columnHeight) {
// maxColumnHeight = columnHeight;
// }
// }
return CGSizeMake(0, self.contentHeight + self.edgeInsets.bottom);
}
@end
#import "ViewController.h"
#import "XMGWaterflowLayout.h"
#import "XMGShop.h"
#import "MJExtension.h"
#import "MJRefresh.h"
#import "XMGShopCell.h"
@interface ViewController () <UICollectionViewDataSource, XMGWaterflowLayoutDelegate>
/** 所有的商品数据 */
@property (nonatomic, strong) NSMutableArray *shops;
@property (nonatomic, weak) UICollectionView *collectionView;
@end
@implementation ViewController
- (NSMutableArray *)shops
{
if (!_shops) {
_shops = [NSMutableArray array];
}
return _shops;
}
static NSString * const XMGShopId = @"shop";
- (void)viewDidLoad {
[super viewDidLoad];
[self setupLayout];
[self setupRefresh];
}
- (void)setupRefresh
{
self.collectionView.header = [MJRefreshNormalHeader headerWithRefreshingTarget:self refreshingAction:@selector(loadNewShops)];
[self.collectionView.header beginRefreshing];
self.collectionView.footer = [MJRefreshAutoNormalFooter footerWithRefreshingTarget:self refreshingAction:@selector(loadMoreShops)];
self.collectionView.footer.hidden = YES;
}
- (void)loadNewShops
{
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
NSArray *shops = [XMGShop objectArrayWithFilename:@"1.plist"];
[self.shops removeAllObjects];
[self.shops addObjectsFromArray:shops];
// 刷新数据
[self.collectionView reloadData];
[self.collectionView.header endRefreshing];
});
}
- (void)loadMoreShops
{
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
NSArray *shops = [XMGShop objectArrayWithFilename:@"1.plist"];
[self.shops addObjectsFromArray:shops];
// 刷新数据
[self.collectionView reloadData];
[self.collectionView.footer endRefreshing];
});
}
- (void)setupLayout
{
// 创建布局
XMGWaterflowLayout *layout = [[XMGWaterflowLayout alloc] init];
layout.delegate = self;
// 创建CollectionView
UICollectionView *collectionView = [[UICollectionView alloc] initWithFrame:self.view.bounds collectionViewLayout:layout];
collectionView.backgroundColor = [UIColor whiteColor];
collectionView.dataSource = self;
[self.view addSubview:collectionView];
// 注册
[collectionView registerNib:[UINib nibWithNibName:NSStringFromClass([XMGShopCell class]) bundle:nil] forCellWithReuseIdentifier:XMGShopId];
self.collectionView = collectionView;
}
#pragma mark - <UICollectionViewDataSource>
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
self.collectionView.footer.hidden = self.shops.count == 0;
return self.shops.count;
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
XMGShopCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:XMGShopId forIndexPath:indexPath];
cell.shop = self.shops[indexPath.item];
return cell;
}
#pragma mark - <XMGWaterflowLayoutDelegate>
- (CGFloat)waterflowLayout:(XMGWaterflowLayout *)waterflowLayout heightForItemAtIndex:(NSUInteger)index itemWidth:(CGFloat)itemWidth
{
XMGShop *shop = self.shops[index];
return itemWidth * shop.h / shop.w;
}
- (CGFloat)rowMarginInWaterflowLayout:(XMGWaterflowLayout *)waterflowLayout
{
return 20;
}
- (CGFloat)columnCountInWaterflowLayout:(XMGWaterflowLayout *)waterflowLayout
{
if (self.shops.count <= 50) return 2;
return 3;
}
- (UIEdgeInsets)edgeInsetsInWaterflowLayout:(XMGWaterflowLayout *)waterflowLayout
{
return UIEdgeInsetsMake(10, 20, 30, 100);
}
@end
