title: Resize UICollectionView cells after their data has been set
body: <p>My UICollectionView cells contain UILabels with multiline text.  I don't know the height of the cells until the text has been set on the label.  </p>
  
  <pre><code>-(CGSize)collectionView:(UICollectionView *)collectionView
                   layout:(UICollectionViewLayout*)collectionViewLayout
   sizeForItemAtIndexPath:(NSIndexPath *)indexPath;
  </code></pre>
  
  <p>This was the initial method I looked at to size the cells. However, this is called BEFORE the cells are created out of the storyboard.</p>
  
  <p>Is there a way to layout the collection and size the cells AFTER they have been rendered, and I know the actual size of the cell?</p>