title: Should I use DialogFragment to show a dialog?
body: <p>If I want to show the dialog, I can just write these code:</p>
  
  <pre><code>AlertDialog.Builder builder = new AlertDialog.Builder(this);
  builder.show();
  </code></pre>
  
  <p>But when I see the API, it says that we should create a class to inherit <code>DialogFragment</code>. So my question is should I always use the <code>DialogFragment</code> class? And in which case I can only use this class?</p>