title: Change Drawable Based on Theme
body: <p>I've got an image in two different colors, corresponding to two different themes in Android.  I want to use them in my Action Bar.  I want to refer to a drawable for the icon, theme agnostic, but have that drawable reference the light color for the light theme, and the dark color for the light theme.</p>
  
  <p>In the menu:</p>
  
  <pre><code>    &lt;item
          android:id="@+id/menu_attach_existing_picture"
          android:icon="@drawable/buttonface_picture"
          android:showAsAction="always"
          android:title="@string/menu_attach_existing_picture"&gt;
      &lt;/item&gt;
  </code></pre>
  
  <p>Then in the styles I want to have something that maps @drawable/buttonface_picture to @drawable/buttonface_picture_light in the light theme and @drawable/buttonface_picture_dark for the dark theme.</p>
  
  <p>I feel like there's got to be a way, but I'm having trouble finding the syntax.  If it changes anything, I am using ActionBarSherlock.</p>