ios development Novice

I created a UIViewController viewController
In his xib added a label

Then use
in the delegate method[Self.window addSubView: viewController.view]; why not find view
view not already inherited it?
Reply:

 
/ / Set the view controller as the window's root view controller and display. 
self.window.rootViewController = self.viewController; 
[Self.window makeKeyAndVisible]; 

Reply:
Why I did not?

cited a floor richdevos reply:

C / C + + code

/ / Set the view controller as the window's root view controller and display.
self.window.rootViewController = self.viewController;
[Self.window makeKeyAndVisible];

Reply:
You do this viewController initialized
Reply:
Because you did not add [self.window makeKeyAndVisible]; phrase it,?
Reply:
[Self.window.viewController addSubView: view];
[Self.window makeKeyAndVisible];

Reply:
Married compiler prompts view property does not exist

references, 4th Floor lzero1319 reply:

because you did not add [self.window makeKeyAndVisible]; phrase it,

?
Reply:
How to initialize?

reference to the third floor volcan1987 reply:

you this viewController initialized yet

Reply:
Not [window addSubview: viewController.view]? It okay
Why always such?

references, 5th Floor bear1122ccc reply:

[self.window.viewController addSubView: view];
[Self.window makeKeyAndVisible];