title: Android: Button selector not parsing
body: <p>I set a button style to use a selector XML as the button background.</p>
  
  <p>The button had the sytle set like this:</p>
  
  <pre><code>android:buttonStyle="@style/arrow_left"
  </code></pre>
  
  <p>Where arrow_left is the name of the style.</p>
  
  <p>The style set the background like this:</p>
  
  <pre><code>android:background="@drawable/arrow_left"
  </code></pre>
  
  <p>Where arrow_left is the name of the selector XML.</p>
  
  <p>The selector had these attributes:</p>
  
  <pre><code>android:state_pressed="true"
  android:drawable="@drawable/button_03p"/&gt;
  </code></pre>
  
  <p>Where button_03p is a PNG in the drawable folder.</p>
  
  <p>The graphical layout gave me an error that said it couldn't parse the XML because the android:drawable tag required a drawable object.</p>
  
  <p>Why does it not recognize the PNG as drawable?  This works in the layout XML:</p>
  
  <pre><code>android:background="@drawable/button_03p"
  </code></pre>
  
  <p>So why would the PNG not be recognized in the selector XML?</p>