title: Change Color of UICollectionViewCell on touch
body: <p>I have an array of cells in a collection view that I want to get to act like buttons.</p>
  
  <p>When I tap on one, I want that cell to highlight, and then change colors.</p>
  
  <p>I'm able to initially set the color of the view.backgroundColor inside of the collectionViewCell us the <code>cellForItemAtIndexPath</code> method. However, contrary to what I thought would work if I do this:</p>
  
  <pre><code>func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
      let cell: ButtonCollectionCell = collectionView.dequeueReusableCellWithReuseIdentifier("ButtonCell", forIndexPath: indexPath) as! ButtonCollectionCell
      cell.cellBackgroundView.backgroundColor = UIColor.darkGrayColor()
  }
  </code></pre>
  
  <p>the color still isn't changing...</p>
  
  <p>Essentially I want these cells to behave exactly like a button. I want them to highlight to a lighter gray color upon touch (they are initially white) after I release my finger I want them to become a dark gray color.</p>
  
  <p>If I touch again I want them to again highlight to a lighter gray color, and then become white again.</p>
  
  <p>If <code>didSelectItemAtIndexPath</code> isn't the way to do it, what is?</p>