title: Listening across activities in Android
body: <p>how can I listen, in an activity, to an event triggered in another activity?</p>
  
  <p>More specifically, I created a menu with an activity to connect to facebook and get the user's friends (as soon as the user is logged, the friend list is automatically and asynchronously requested and, on onComplete event, fills a global ArrayList). Say the user leaves the menu before the request is completed, and goes to another activity which shows the list of friends. To fill the list, I need to know if the getfriends request is complete and the ArrayList is filled. If it's not, I need to know when it is done to start filling my list of friends. I'm not sure whether the asynchronous request is killed when leaving the activity, and, if not, how can I know it's completed.</p>
  
  <p>Can it be achieved? </p>
  
  <p>Thank you</p>