title: Load colours from file according to theme
body: <p>My app shows loads of messages from the server and the type of message determines what colour span is applied to it. I already have a dark theme for my app and now I want to add a light theme but the colours for the dark theme can't be re-used as the messages become unreadable against a white background.</p>
  
  <p>At the moment, I have the colours stored in the following RGB format in an xml file under /values:</p>
  
  <pre><code>&lt;integer-array name="xyz_message_type"&gt;
      &lt;item&gt;001&lt;/item&gt; &lt;!--Red--&gt;
      &lt;item&gt;002&lt;/item&gt; &lt;!--Green--&gt;
      &lt;item&gt;003&lt;/item&gt; &lt;!-Blue--&gt;
  &lt;/integer-array&gt;
  </code></pre>
  
  <p>and the appropriate colour is selected by passing the R.array.xyz_message_type value to a dedicated class which retrieves and parses the colour.</p>
  
  <p>What would be the easiest way to alter my app to load a 'light' set of colours when the theme is changed? If my approach can be improved, what would be a better way to handle this?</p>