Notifying an activity that it needs to make an update
<p>I've read that it's bad practice for an activity in the foreground to try to communicate/manipulate an activity in the background, and that generally the onResume function should be used.</p>

<p>So I've got one activity that lets a user add a "favorite" thing.  There's another activity that shows a list of all the favorited things.  Instead of querying the DB and rebuilding the list each time onResume, I'm using a class with just static flags like "favorites_updated", and if it's true, onResume we do the extra work - if it's false we don't bother.</p>

<p>This feels a little clunky - is there a more established way of doing something like this?</p>

<p>TYIA.</p>
