title: Error in sizing UICollectionViewCell in Swift
body: <p>I am trying to adjust the size of each collection view cell according to the length of the label text contained within</p>
  
  <pre><code>func collectionView(collectionView: UICollectionView, layout collectionViewLayout:UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -&gt; CGSize {
      var size = CGSize()    
      var cell = collectionView.dequeueReusableCellWithReuseIdentifier("lessonCell", forIndexPath: indexPath) as UICollectionViewCell
      var label: UILabel = cell.viewWithTag(300) as UILabel
      var labelSize = label.frame.size
      size = labelSize
      return size
  }
  </code></pre>
  
  <p>When running the code, the app crashes with the error 'negative or zero sizes are not supported in the flow layout.' However, when I stepped through, I found that the crash occurs in initializing the cell variable, before the size is even determined. Why would initializing my cell variable throw this type of error?</p>