[_collectionView scrollToItemAtIndexPath:[NSIndexPath indexPathForItem:_biao inSection:0] atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally animated:YES];
一定要在collectionview加载完再调用此代码,[collectionview reloadData]之后
[_collectionView scrollToItemAtIndexPath:[NSIndexPath indexPathForItem:_biao inSection:0] atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally animated:YES];
一定要在collectionview加载完再调用此代码,[collectionview reloadData]之后