collection view 根据delegate来布局cell的大小

@protocol UICollectionViewDelegateFlowLayout <UICollectionViewDelegate>

@optional

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath;

...

@end

于是把collection view 的delegate 由 <UICollectionViewDelegate>换成<UICollectionViewDelegateFlowLayout>并实现

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
return CGSizeMake(width, height);
}

collection view 根据delegate来布局cell的大小

原文：http://blog.csdn.net/zhangping871/article/details/44645983