title: Android TransitionDrawable with multiple items
body: <p>I want to create a Button in Android with a text, and a background image. The background image should crossfade every X time.</p>
  
  <p>I have this working using a TransitionDrawable with 2  images.</p>
  
  <p>But I can't get this to work with more than 2 images.</p>
  
  <p>What I have :</p>
  
  <p>In Java code I create a Button and set a background (which is a TransitionDrawable defined in XML). And I start the transition.</p>
  
  <pre><code>final Button b = new Button(getApplicationContext());
  b.setTextColor(getResources().getColor(R.color.white));
  b.setText("Some text");
  b.setBackgroundDrawable(getResources().getDrawable(R.drawable.tile));
  StateListDrawable background = (StateListDrawable) b.getBackground();
  TransitionDrawable td = (TransitionDrawable) background.getCurrent();
  td.startTransition(2000);
  </code></pre>
  
  <p>In XML I define in tile.xml</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;selector xmlns:android="http://schemas.android.com/apk/res/android"&gt;
      &lt;item android:state_pressed="true" &gt;
          &lt;shape&gt;
              &lt;solid
                  android:color="#449def" /&gt;
          &lt;/shape&gt;
      &lt;/item&gt;
      &lt;item android:drawable="@drawable/transition"&gt;
          &lt;shape&gt;
              &lt;solid
                  android:color="#0000ff" /&gt;
          &lt;/shape&gt;
      &lt;/item&gt;
  &lt;/selector&gt; 
  </code></pre>
  
  <p>And finally a transition.xml</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;transition xmlns:android="http://schemas.android.com/apk/res/android"     android:oneshot="false"&gt;
    &lt;item android:drawable="@drawable/desert"/&gt; 
    &lt;item android:drawable="@drawable/hydrangeas" /&gt; 
    &lt;item android:drawable="@drawable/jellyfish" /&gt; 
  &lt;/transition&gt; 
  </code></pre>
  
  <p>Now the effect is that when I start the app the desert image is shown. This image crossfades to the hydrangeas image as it should. But the jellyfish image is never shown.</p>
  
  <p>In the doc for TransitionDrawables it is stated that you can specify more than 2 drawables but I can't get this to work.</p>
  
  <p>I also tried this without any XML but in pure JAVA but this gave exactly the same problem :-(</p>