title: how to find the length of a set?
body: <p>I'm trying to find the lentgh of a set from a preference.
  I tired set.length, but it doesnt work. Anyone know another way to find a length of a set?</p>
  
  <pre><code>   set = prefs.getStringSet("key", null);
              int X = set.length; //it doesn't like length....
  </code></pre>