I have an application, say \'MyApp\', which by default loads the view controller \'MyAppViewController\' whenever the application launches. Later, I added a new view control
Most likely your main NIB file is still set to "MainWindow", check your *-Info.plist file.
If that's the case you can open the MainWindow.xib in Interface Builder. You should see a View Controller item. Bring up the inspector window and change the Class Identity to point to your new class. That should take care of instantiating your class.
As this feels like a "newbie" question (please pardon me if I'm mistaken) I would also highly recommend the following article:
iPhone Programming Fundamentals: Understanding View Controllers
Helped me understand the whole ViewController thing and the IB interaction..
As for me with xcode 4.3.3, all I had to do was simply replace all references of 'MyAppViewController' with 'NewViewController' in the AppDelegate h and m files.
Perhaps all the other steps have been taken out in the newer versions of xcode.
Hope this helps.
Its easy, just:
MainWindow.xib
and replace MyAppViewController with NewViewController.application:didFinishLaunchingWithOptions:
add NewViewController's view to the window instead of MyAppViewController's view.