title: Setting Android Background & Persistence Menu Bar - Using attribute on older versions causes crash - Is there a theme /pattern approach?
body: <p>In Android 3.0, the concept of "checked" can be rendered using an "activated" background. This gives you the persistent bar you see when you tap on a list fragment, providing context for the fragment to the list's right (e.g., tapping on a folder in Gmail highlights that folder and opens up another list fragment to show the conversations in that folder).</p>
  
  <p>For example, the fragment samples show stuff like:</p>
  
  <pre><code>setListAdapter(new ArrayAdapter&lt;String&gt;(getActivity(),
                      android.R.layout.simple_list_item_activated_1, Shakespeare.TITLES));
  </code></pre>
  
  <p>That resource (<code>android.R.layout.simple_list_item_activated_1</code>) is new to Android 3.0. What makes it "activated" is:</p>
  
  <pre><code>android:background="?android:attr/activatedBackgroundIndicator"
  </code></pre>
  
  <p>That attribute value is new to Android 3.0 and will cause you to crash if you try using it on earlier versions of Android, from what I can tell. I want to set the background to this magic value for the 3.0/large/landscape combination, and skip it otherwise.</p>
  
  <p>I can accomplish this by having two separate versions of the layout, one in a <code>-v11</code> resource set, one in a regular resource set. This is a bit less DRY than I'd like, though, since the bulk of the layout is the same, with only this one attribute either being included or being skipped.</p>
  
  <p>I took a stab at trying to use drawable resource aliases, so the <code>android:background</code> could refer to the alias and the alias would handle the <code>-v11</code> differentiation, but <code>&lt;bitmap&gt;</code> drawables don't seem to like <code>android:src="@null"</code>.</p>
  
  <p>I suspect there's a styles-and-themes approach to this problem, but since I've never fully wrapped my head around those (one of my more embarrassing Android knowledge gaps), I'm not completely sure what to do.</p>
  
  <p>Has anyone worked out a pattern for using "activated" on 3.0 and skipping it on pre-3.0, beyond separate layouts?</p>
  
  <p>Thanks!</p>