title: What's packageContext in Intent#(Context packageContext, Class<?> cls)?
body: <p>The document says :</p>
  
  <blockquote>
    <p>packageContext    A Context of the
    application package implementing this
    class.</p>
  </blockquote>
  
  <p>But what does it mean? which class is "this class"?</p>
  
  <p>Why <code>new Intent(this,XXX.class)</code> works?</p>