Nested UICollectionViews, AutoLayout and rotation in iOS 8

Question

I started to use AutoLayout for a large project and was positively surprised about it. However, now I have to adjust the project to accommodate for rotation and size classes, an

Answer 1

I too had the same problem, with the other answers I found that the layout was getting letterboxed. I got closer to what I wanted with this:

 override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {

        super.viewWillTransition(to: size, with: coordinator)
        coordinator.animate(alongsideTransition: nil, completion:  { context in

            self.collectionView?.collectionViewLayout.invalidateLayout()
            self.collectionView?.collectionViewLayout.finalizeCollectionViewUpdates()

        })

    }