title: ListView custom selected icon
body: <p>I have a ListView where the user can select something:</p>
  
  <pre><code>&lt;ListView
      android:id="@+id/poll_list"
      android:layout_width="match_parent"
      android:layout_height="0dp"
      android:layout_weight="1"
      android:choiceMode="singleChoice"
      android:listSelector="#666" /&gt;
  </code></pre>
  
  <p>That works fine. When the user picks something, the item gets colored with <code>#666</code>. But I would prefer it to display a custom icon instead. Eg. a right aligned checkmark graphic.</p>
  
  <p>I could include that graphic in my item's view. But how do I display it based on the state (without having to let the Adapter having to keep track of the checked state and invalidate all the data all the time)?</p>
  
  <p>In CSS it would be a right aligned background graphic visible on <code>:active</code> only. But how to do it in Android? I think it should be possible with a custom drawable somehow.</p>