UICollectionViewFlowLayout * flowLayout = [[UICollectionViewFlowLayout alloc]init];


滚动方向:

flowLayout.scrollDirection = UICollectionViewScrollDirectionHorizontal ;

行间距(最小)

flowLayout.minimumLineSpacing = 0;

列间距(最小)
flowLayout.minimumInteritemSpacing = 30;

item大小
flowLayout.itemSize = CGSizeMake(40, 30);

setcion 的边距
flowLayout.sectionInset = UIEdgeInsetsMake(10, 10, 10, 10);

header 大小
flowLayout.headerReferenceSize = CGSizeMake(320, 20);

footer大小
flowLayout.footerReferenceSize = CGSizeMake(320, 20);


重用标志

static NSString * cellidentifier = @"cell";


注册重用标识符
[cView registerClass:[MyCollectionViewCell class] forCellWithReuseIdentifier:cellidentifier];

Cell 重用

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
MyCollectionViewCell * cell = [collectionView dequeueReusableCellWithReuseIdentifier:cellidentifier forIndexPath:indexPath];
cell.backgroundColor = [UIColor redColor];
cell.textLavel.text = [NSString stringWithFormat:@"%ld",(long)indexPath.row];

return cell;
}