title: How to trigger a function on a old Activity when returning from a newer activity?
body: <p>i am wanting to Trigger a event on the old activity when returning back from the newer activity.</p>
  
  <p>so when i hit the Done button and im using <code>Finish();</code> to return back to the old  Activity this works but i need to update the ui on the old activity.
  do i set up for a <code>OnActivityResultListener</code>? and handle it that way? im not exactly sure how to set that up but im sure there is plenty of info on that else were.</p>