title: Android back button new intent or finish()
body: <p>I have a question. I have a list view (A) and a details view (B).</p>
  
  <p>On B, I have a "view list" button that will always take the user to the list. The thing is, I can get to B via a notification and not necessarily from A.</p>
  
  <p>So when clicking B, I can't just use finish() because I could have come in from a notification, so I may need to start a new activity in some cases.</p>
  
  <p>How do I reliably tell if I came in from A or from a notification so that I can take the right action.</p>
  
  <p>Added to that, is this something I should be worrying about? Or is it ok just to start an activity every time. In the case where I bouncing between A -> B -> A -> B -> A -> B over and over... never once calling finish()... will that slow things down?</p>
  
  <p>Thanks,</p>
  
  <p>Gerard.</p>