title: iPhone: refresh UIViewController on applicationWillEnterForeground
body: <p>my question is related to <a href="https://stackoverflow.com/q/4919950/602011">applicationWillEnterForeground: reload Data from ViewController</a>. I want to reload view when application will enter foreground. But I have a lot of Views. How to know which view to reload ? Because I dont want to reload all views in  applicationWillEnterForeground: method.</p>