title: Android application event handling
body: <p>Is there a standard set of Listener/Observer/Observable classes in Android for managing application events in Android? </p>
  
  <p>I'm not talking about UI or other Android API events, but rather custom app events like <code>GameOverEvent</code>, <code>LevelClearedEvent</code>, etc. </p>
  
  <p>Is there a preferred interface to implement/extend so that I can implement things like:</p>
  
  <pre><code>public void addGameOverListener(GameOverListener listener)
  </code></pre>