title: Difference between setSupportActionBar and setActionBar
body: <p>So I am trying to use a Toolbar as an ActionBar in an app. I am trying to use the <code>setSupportActionBar()</code> method in a fragment that is hosted by an activity that extends a class that extends <code>AppCompatActivity</code>. For some reason I'm not able to do <code>getActivity().setSupportActionBar()</code> at all, I can only do <code>getActivity().setActionBar()</code>. The problem with this is that <code>setSupportActionBar()</code> accepts an <code>android.support.v7.widget.Toolbar</code> where <code>setActionBar()</code> accepts only an  android.widget.Toolbar. This causes my app to be restricted to only devices using Lollipop. </p>
  
  <p>A side issue I've found is that when trying to change the theme of my Toolbar to dark with </p>
  
  <pre><code>app:theme="@style/ThemeOverlay.AppCompat.Dark"
  </code></pre>
  
  <p>it doesn't work.</p>