OC UICollectionView 滚动完全显示item

    ///滚动到指定item
    [self.collectionView scrollToItemAtIndexPath:[NSIndexPath indexPathForItem:indexPath.item inSection:0] atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally animated:YES];

UICollectionView 自动将被选中的cell滚动到正中

http://blog.sina.com.cn/s/blog_8070e98f0102xg0f.html