title: How to set opacity on UICollectionView background without affect opacity of UICollectionViewCell?
body: <p>I have set the color of a <code>UICollectionView</code> with an <code>image</code> pattern like so:</p>
  
  <pre><code>self.collectionView.backgroundColor = [UIColor colorWithPatternImage:image];
  </code></pre>
  
  <p>I would like to set the alpha of the <code>collectionView</code> without affecting the alpha of the <code>UICollectionViewCell</code>. Is there a way to do this? Setting the alpha of <code>collectionView</code> also affects the <code>UICollectionViewCell</code>, so I already tried that. What else should I try/what else will actually work?</p>
  
  <p>Thanks for any tips.</p>