Let say someone is using my app and the change the settings in the settings bundle, when they come back to my app I would like my view to update (via my updating method) according to those settings. I've tried many different things but I just can't get it to work.
What is the best way to implement this kind of behavior for my iPhone app?
It's worth noting that you're not limited to the AppDelegate; you can listen for these events from anywhere in your code with an NSNotification. See this answer for more details on how to listen for UIApplicationDidBecomeActiveNotification.