瀑布流

import "ViewController.h"

import "XRCollectionViewCell.h"

import "XRWaterfallLayout.h"

import "XRImage.h"

@interface ViewController ()
@property (nonatomic, strong) UICollectionView *collectionView;
@property (nonatomic, strong) NSMutableArray>images;
@end
@implementation ViewController

• (NSMutableArray *)images {
  //从plist文件中取出字典数组，并封装成对象模型，存入模型数组中
  if (!_images) {
  _images = [NSMutableArray array];
  NSString *path = [[NSBundle mainBundle] pathForResource:@"1.plist" ofType:nil];
  NSArray *imageDics = [NSArray arrayWithContentsOfFile:path];
  for (NSDictionary *imageDic in imageDics) {
  XRImage *image = [XRImage imageWithImageDic:imageDic];
  [_images addObject:image];
  }
  }
  return _images;
  }
• (void)viewDidLoad {
  [super viewDidLoad];
  //创建瀑布流布局
  XRWaterfallLayout *waterfall = [XRWaterfallLayout waterFallLayoutWithColumnCount:3];
  //或者一次性设置
  [waterfall setColumnSpacing:10 rowSpacing:10 sectionInset:UIEdgeInsetsMake(10, 10, 10, 10)];
  //设置代理，实现代理方法
  waterfall.delegate = self;
  //创建collectionView
  self.collectionView = [[UICollectionView alloc] initWithFrame:self.view.bounds collectionViewLayout:waterfall];
  self.collectionView.backgroundColor = [UIColor whiteColor];
  [self.collectionView registerNib:[UINib nibWithNibName:@"XRCollectionViewCell" bundle:nil] forCellWithReuseIdentifier:@"cell"];
  self.collectionView.dataSource = self;
  [self.view addSubview:self.collectionView];
  }
• (void)click {
  [self.images removeAllObjects];
  [self.collectionView reloadData];
  }
  //根据item的宽度与indexPath计算每一个item的高度
• (CGFloat)waterfallLayout:(XRWaterfallLayout *)waterfallLayout itemHeightForWidth:(CGFloat)itemWidth atIndexPath:(NSIndexPath *)indexPath {
  //根据图片的原始尺寸，及显示宽度，等比例缩放来计算显示高度
  XRImage *image = self.images[indexPath.item];
  return image.imageH / image.imageW * itemWidth;
  }
• (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
  return self.images.count;
  }
• (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
  XRCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"cell" forIndexPath:indexPath];
  cell.imageURL = self.images[indexPath.item].imageURL;
  return cell;
  }

XRImage.h

import

import

@interface XRImage : NSObject
@property (nonatomic, strong) NSURL *imageURL;
@property (nonatomic, assign) CGFloat imageW;
@property (nonatomic, assign) CGFloat imageH;

• (instancetype)imageWithImageDic:(NSDictionary *)imageDic;

XRImage.m

• (instancetype)imageWithImageDic:(NSDictionary *)imageDic {
  XRImage *image = [[XRImage alloc] init];
  image.imageURL = [NSURL URLWithString:imageDic[@"img"]];
  image.imageW = [imageDic[@"w"] floatValue];
  image.imageH = [imageDic[@"h"] floatValue];
  return image;
  }

XRCollectionViewCell.h

@property (nonatomic, strong) NSURL *imageURL;

XRCollectionViewCell.m

import

@property (weak, nonatomic) IBOutlet UIImageView *imageView;
@end
@implementation XRCollectionViewCell

• (void)setImageURL:(NSURL *)imageURL {
  _imageURL = imageURL;
  [self.imageView sd_setImageWithURL:imageURL placeholderImage:[UIImage imageNamed:@"placeholder"]];
  }
  @end
  

  //

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