UICollectionViewCell disappears when settings contentOffset

Question

I have created a UICollectionView that slides its items based on a certain trigger. I'm trying to animate the cells transition by:

            UIView.animate(withDuration: 0.4,
                           delay: 0.5, animations: {

                            self.headingsCollectionView.contentOffset = CGPoint(x: x, y: 0)
                            self.headingsCollectionView.reloadItems(at: [indexPath])
            })

The animation is successful, the problem is when I change the CollectionView contentOffset the current item disappears instead of scrolling off.

I tried reloading the current item (as suggested here) so it would stay visible but it's still not working.
I've tried scrollToItemAtIndexPath:atScrollPosition:animated but it's not animating the item transition.
setContentOffset:animated Tried it, it doesn't animate as well.

remove self.headingsCollectionView.reloadItems(at: [indexPath]) — Sandeep Bhandari, Jun 01 '17 at 12:05
@SandeepBhandari I tried without it but it's still disappearing. — Shawerma, Jun 01 '17 at 12:18
`scrollToItemAtIndexPath:atScrollPosition:animated` should do the trick if you have implemented it correctly — Rijo Payyappilly, Jun 01 '17 at 13:01
@RijoPayyappilly Could you please elaborate on the correct implementation for it? — Shawerma, Jun 03 '17 at 10:58

score 4 · Answer 1 · answered Nov 15 '17 at 07:47

4

Because you are using UIView.animate method, you have to put self.view.layoutIfNeeded() after programmatically setting contentOffset

 UIView.animate(withDuration: 0.4,
                   delay: 0.5, animations: {

                    self.headingsCollectionView.contentOffset = CGPoint(x: x, y: 0)
                    self.headingsCollectionView.reloadItems(at: [indexPath])
                    self.view.layoutIfNeeded()
    })

answered Nov 15 '17 at 07:47

Dimitar Stefanovski

859
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I thought some dark magic it was. Thank you for clearing this out! – Artem Zaytsev Sep 12 '19 at 16:36

UICollectionViewCell disappears when settings contentOffset

1 Answers1