title: Android - detecting application launch from home or history
body: <p>What is the best way to detect when an Android "Application" has been launched from the Home screen/History screen?</p>
  
  <p>Basically, what I'm trying to achieve is force the user to login to certain screens each time they come back to the app (i.e. they have full access to all activities once logged in, but essentially I want them to re-authenticate when they come back to the app via launching on the home screen).  </p>
  
  <p>I know similar questions have been asked before (i.e. how to log launches of an app) - but none that I have seen has yet been able to solve my problem.  All ideas welcome...</p>