title: Android: start new activity on orientation changed, without recreating old activity
body: <p>I need to start new activity when user sets the device in landscape orientation without changing orientation of the old activity.</p>
  
  <p>So, I have 2 activities:</p>
  
  <ul>
  <li>(1) Old activity in portrait only</li>
  <li>(2) New activity in landscape only</li>
  </ul>
  
  <p>The app scenario looks like this:</p>
  
  <ul>
  <li>user is in (1) old activity in portrait mode</li>
  <li>user puts his device landscape, I need to start (2) new activity</li>
  <li>user is in (2) new activity and presses Back button. I need to finish new (2) activity and come back to (1) old activity which
  should be still in portrait orientation (even if the device is in
  landscape orientation).</li>
  </ul>
  
  <p>Any idea how to achieve this?</p>