title: Making GridView items square
body: <p>I would like the items of my <code>GridView</code> to be square. There are 2 columns and the items width is <code>fill_parent</code> (e.g. they take as much horizontal space as possible. The items are custom views.</p>
  
  <p>How do I make the items height to be equal to their variable width?</p>