平时使用UITableView比较多，一直对CollectionView不怎么熟悉，为了加深对CollectionVew的理解，特意写几个小的Demo熟悉一下。

colectionView.gif

关键代码：

 _collectionView = ({
        
        UICollectionViewFlowLayout *layout = [UICollectionViewFlowLayout new];
        layout.itemSize = CGSizeMake(130, 130);
        layout.scrollDirection = UICollectionViewScrollDirectionHorizontal;
        layout.minimumLineSpacing = 2;

        UICollectionView *collectionView = [[UICollectionView alloc]initWithFrame:CGRectMake(0, 244, self.view.frame.size.width,130) collectionViewLayout:layout];
        collectionView.backgroundColor = [UIColor whiteColor];
        collectionView.delegate = self;
        collectionView.dataSource = self;
        collectionView.scrollsToTop = NO;
        collectionView.showsVerticalScrollIndicator = NO;
        collectionView.showsHorizontalScrollIndicator = NO;
        [collectionView registerClass:[MyCollectionViewCell class] forCellWithReuseIdentifier:kMyCollectionViewCellID];
        [self.view addSubview:collectionView];
        collectionView;
    });

设置代理

#pragma mark - UICollectionViewDataSource
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{
    return 8;
}


- ( UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
     return [collectionView dequeueReusableCellWithReuseIdentifier:kMyCollectionViewCellID forIndexPath:indexPath];
}

#pragma mark - UICollectionViewDelegateFlowLayout

- (void)collectionView:(UICollectionView *)collectionView willDisplayCell:(UICollectionViewCell *)cell forItemAtIndexPath:(NSIndexPath *)indexPath {
    [(MyCollectionViewCell *)cell configureCellWithPostURL:@"postImage.jpg"];
}

```

[GitHub地址： https://github.com/JnLuffy/CollectionViewDemo1](https://github.com/JnLuffy/CollectionViewDemo1)