title: Hiding Android title bar only in landscape mode
body: <p>I have an activity and want to have these conditions:</p>
  
  <ul>
  <li>My activity has title bar in portrait mode.</li>
  <li>The title bar will hide when I turn the device to go to landscape mode.</li>
  <li>The activity should not to recreate when goes to landscape mode, by using "configChanges" in Manifest.</li>
  </ul>
  
  <p>I know this question is asked before, but no correct answer I found.</p>