Keeping the contentOffset in a UICollectionView while rotating Interface Orientation

Question

I\'m trying to handle interface orientation changes in a UICollectionViewController. What I\'m trying to achieve is, that I want to have the same contentOffset afte

Answer 1

What does the job for me is this:

1. Set the size of your my cells from your my UICollectionViewDelegateFlowLayout method

   func collectionView(collectionView: UICollectionView!, layout collectionViewLayout: UICollectionViewLayout!, sizeForItemAtIndexPath indexPath: NSIndexPath!) -> CGSize
   {
       return collectionView.bounds.size
   }
   

2. After that I implement willRotateToInterfaceOrientationToInterfaceOrientation:duration: like this

   override func willRotateToInterfaceOrientation(toInterfaceOrientation: UIInterfaceOrientation, duration: NSTimeInterval) 
   {
       let currentPage = Int(collectionView.contentOffset.x / collectionView.bounds.size.width)
   
       var width = collectionView.bounds.size.height
       UIView.animateWithDuration(duration) {
           self.collectionView.setContentOffset(CGPointMake(width * CGFloat(currentPage), 0.0), animated: false)
           self.collectionView.collectionViewLayout.invalidateLayout()
       }
   }
   

The above code is in Swift but you get the point and it's easy to "translate"