UICollectionViewFlowLayout Size Warning When Rotating Device to Landscape

I was getting the same warning. Unsatisfied with the "reloadData" approach, I found that calling [self.collectionView.collectionViewFlowLayout invalidateLayout] before setting the frame of the collection view silenced the warning and yielded the expected results.

Not to throw another shrimp on this loaded, yet unaccepted, barbie.

- (CGSize)collectionView:(UICollectionView *)collectionView                   layout:(UICollectionViewLayout *)collectionViewLayout  sizeForItemAtIndexPath:(NSIndexPath *)indexPath {    [collectionView setContentInset:UIEdgeInsetsMake(0, 0, 0, 0)];    return CGSizeMake(100, collectionView.frame.size.height);}

Setting the content insets just before returning the cell size did the trick for me.

Note:

I am using a container view in a storyboard to load the collection view within a UIViewController. I tried setting this on the flowLayout object in the storyboard. The collection view in the storyboard. And overriding one of the UICollectionViewDelegateFlowLayout; though I do not remember which one. I'm also not sure if this will work for a vertical layout.

In

[UIViewController willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration]

I called the, [UICollectionViewLayout invalidateLayout] and seems to work good.