how use the nib file in cocos2dx

I wanna use the nib file in my app, I am already create a app by cocos2dx cpp template , and the RootViewController.mm and RootViewConntroll.h created the same. I created the RootViewController.nib.
and change the code like this
viewController = [[RootViewController alloc] initWithNibName:@“RootViewController” bundle:nil]; in AppController.mm. and remove the “//” in RootViewController.mm.
Run the App,but the nib was not running.