title: getActionBar() returns null
body: <p>I'm having an odd problem.
  I am making an app with targetsdk 13. </p>
  
  <p>In my main activity's onCreate method i call <code>getActionBar()</code> to setup my actionbar. This works fine when running on the Android 3.2 emulator, but when using Android 3.0 and 3.1 the <code>getActionBar()</code> method returns null.</p>
  
  <p>I find this extremely odd, and i cannot see any reason why it would do so.
  Is this a bug with the emulators or is there something i need to do, in order to ensure that my application has an actionbar? </p>
  
  <p><strong>SOLUTION:</strong>
  I think I've found a solution for this problem.
  I wasn't using the setContentView to set a layout for the activity. Instead I was using <code>fragmentTransaction.add(android.R.id.content, mFragment, mTag)</code> to add a fragment to the activity.
  This worked fine in 3.2, but in earlier honeycomb versions the action bar is apparently not set if you don't use the setContentView in the <code>onCreate()</code> method.
  So I fixed it by using the <code>setContentView()</code> method in my <code>onCreate()</code> method and just supplying it with a layout that contained an empty FrameLayout.
  I can still use the <code>fragmentTransaction.add(android.R.id.content, mFragment, mTag)</code> method the same way as before.</p>
  
  <p>It's not the prettiest fix, but it works. </p>