title: Event Bus Index
body: <p>Where/when should I add the index for Green Robot Event Bus library:</p>
  
  <pre><code>EventBus.builder().addIndex(new MyEventBusIndex()).installDefaultEventBus();
  </code></pre>
  
  <p>as described <a href="http://greenrobot.org/eventbus/documentation/subscriber-index/" rel="nofollow">here</a>? I've put this onCreate() method of my launcher activity, but sometimes I get:</p>
  
  <pre><code>Caused by: org.greenrobot.eventbus.h: Default instance already exists. It may be only set once before it's used the first time to ensure consistent behavior.
  </code></pre>
  
  <p>Where am I wrong? Many thanks.</p>