How to center a UICollectionView when it is tapped?

Question

I have a UICollectionView and it has quite a lot of UICollectionViewCells on it. I want to scroll the cell to the centre of the UICollectionView<

Answer 1

Setting contentInsets should give some extra space around first and last cells:

CGFloat collectionViewHeight = CGRectGetHeight(collectionView.bounds);
[collectionView
  setContentInset:
   UIEdgeInsetsMake(collectionViewHeight/2, 0, collectionViewHeight/2, 0) ];
  // nb, those are top-left-bottom-right

After you should call:

[collectionView scrollToItemAtIndexPath:selectedItemPath
    atScrollPosition:UICollectionViewScrollPositionCenteredVertically
    animated:YES];

It's important to pass correct scroll position: UICollectionViewScrollPositionCenteredVertically

This should center tapped item properly.

EDIT

It's really strange, but after setting UIEdgeInsets to collection view method scrollToItemAtIndexPath does not works properly, so i make some modification:

- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
    CGFloat collectionViewHeight = CGRectGetHeight(self.collectionView.frame);
    [collectionView setContentInset:UIEdgeInsetsMake(collectionViewHeight / 2, 0, collectionViewHeight / 2, 0)];

    UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
    CGPoint offset = CGPointMake(0,  cell.center.y - collectionViewHeight / 2);
    [collectionView setContentOffset:offset animated:YES];
}

it works fine for me.