数据来源于豆瓣网~仅供学习交流~

本实例练习用到了SDWebImage框架：实现从网络端下载图片的功能
下载地址：https://github.com/rs/SDWebImage

实现效果及框架：

xib文件：Class是与之相联系的文件

代码部分：
Modal部分
CollectionModal.h

#import <Foundation/Foundation.h>

@interface CollectionModal : NSObject

@property (nonatomic,retain) NSDictionary *images;
@property (nonatomic,copy) NSString *title;

@end

CollectionModal.m 能够什么都不写，也能够重写description来调试用~

View部分
collectionView.h

#import <UIKit/UIKit.h>
#import "CollectionModal.h"

@interface CollectionCell : UICollectionViewCell
//与xib文件相关联
@property (weak, nonatomic) IBOutlet UIImageView *movieImage;
@property (weak, nonatomic) IBOutlet UILabel *nameLabel;

//数据
@property (nonatomic,retain) CollectionModal *modal;

@end

collectionView.m

#import "CollectionCell.h"
#import "UIImageView+WebCache.h"

@implementation CollectionCell

- (void)awakeFromNib {
    // Initialization code
}

- (void)setModal:(CollectionModal *)modal {
    _modal = modal;
    [self setNeedsLayout];
}
//布局，当modal赋值以后，调用此函数
- (void)layoutSubviews {
        [super layoutSubviews];//不要忘了父类方法，不然非常easy出乱七八糟的错误
    _nameLabel.text = _modal.title;

    NSString *str = _modal.images[@"medium"];
    [_movieImage sd_setImageWithURL:[NSURL URLWithString:str]];

}

@end

Controller部分
collectionViewController.h

#import <UIKit/UIKit.h>

@interface CollectionViewController : UIViewController<UICollectionViewDelegateFlowLayout,UICollectionViewDataSource>
//不要忘了遵循协议
{
    UICollectionView *_collectionView;
    NSMutableArray *_modalArray;
}
@end

#import "CollectionViewController.h"
#import "CollectionModal.h"
#import "CollectionCell.h"

#define Zwidth [UIScreen mainScreen].bounds.size.width
#define Zheight [UIScreen mainScreen].bounds.size.height

@interface CollectionViewController ()

@end

@implementation CollectionViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    [self _loadData];
    [self _creatCollectionView];
    // Do any additional setup after loading the view.
}

#pragma mark - Data
//文件解析。载入数据
- (void)_loadData {
    NSString *fliePath = [[NSBundle mainBundle] pathForResource:@"exercise" ofType:@"json"];
    NSData *data = http://www.mamicode.com/[NSData dataWithContentsOfFile:fliePath];"hljs-built_in">NSDictionary *dataDic = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil];
    //    NSLog(@"%@",dataDic);

    _modalArray = [NSMutableArray array];

    NSArray *subjects = dataDic[@"subjects"];
    for (NSDictionary *dic in subjects) {
        CollectionModal *modal = [[CollectionModal alloc] init];
        modal.images = dic[@"images"];
        modal.title = dic[@"title"];
        //        NSLog(@"%@",modal);
        [_modalArray addObject:modal];//将文件载入到数据数组中
    }
}

#pragma mark - collectionView
//创建collectionView
- (void)_creatCollectionView {
    UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];
    layout.minimumInteritemSpacing = 1;//内部cell之间距离
    layout.minimumLineSpacing = 10;//行间距

    layout.itemSize = CGSizeMake((Zwidth-4)/3, 200);
    layout.scrollDirection = UICollectionViewScrollDirectionVertical;//滚动方向设置

    _collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 0, Zwidth, Zheight) collectionViewLayout:layout];
    //代理设置
    _collectionView.dataSource = self;
    _collectionView.delegate = self;

    [self.view addSubview:_collectionView];

    //注冊cell
    UINib *nib = [UINib nibWithNibName:@"CollectionCell" bundle:[NSBundle mainBundle]];
    [_collectionView registerNib:nib forCellWithReuseIdentifier:@"cell"];

}

//协议方法的实现，以下两个方法是必须实现的
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
    return _modalArray.count;
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    //这里包括cell的复用思想
    CollectionCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"cell" forIndexPath:indexPath];
    CollectionModal *modal = _modalArray[indexPath.row];
    cell.modal = modal;
    return cell;
}

AppDelegate.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
    self.window.backgroundColor = [UIColor whiteColor];
    [self.window makeKeyAndVisible];

    CollectionViewController *vc = [[CollectionViewController alloc] init];
    self.window.rootViewController = vc;
    // Override point for customization after application launch.
    return YES;
}

关于数据有想要的。能够评论或私信~哈哈~