title: Retrieving all Drawable resources from Resources object
body: <p>In my Android project, I want to loop through the entire collection of <code>Drawable</code> resources.  Normally, you can only retrieve a specific resource via its ID using something like:</p>
  
  <pre><code>InputStream is = Resources.getSystem().openRawResource(resourceId)
  </code></pre>
  
  <p>However, I want to get all <code>Drawable</code> resources where I <strong>won't</strong> know their ID's beforehand.  Is there a collection I can loop through or perhaps a way to get the list of resource ID's given the resources in my project?</p>
  
  <p>Or, is there a way for me in Java to extract all property values from the <code>R.drawable</code> static class?</p>