How to reference THE UIWindow from sub UIViewControllers?

I am trying to add another subview programmatically based on some event (user taps a button, for instance).

My problem is that I am having problems referencing the (one and only) instance of UIWindow. I reach it from my appDelegate, because the MainWindow.xib and the appDelegate have been wired up. But I cannot reach the UIWIndow from anywhere else (I cannot draw that connection in IB, can I?)

What techniwue is preferred to get a reference to (the one and only) UIWindow? ...so that I in turn can use the following code from my various UIViewControllers:

[myOneAndOnlyWindow addSubview:oneOfManyViews.view];
[myOneAndOnlyWindow makeKey开发者_StackOverflow中文版AndVisible];

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You can retrieve pointer to the key window of your application after call [UIApplication sharedApplication].keyWindow Window becomes key after you call [window makeKeyAndVisible]

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You can use following code to add view in main window from any view controller:

YourAppDelegate *appDelegate = (YourAppDelegate*)[[UIApplication sharedApplication] delegate];
[appDelegate.window addSubView:viewController.view];

The only thing you must take care is that window should be defined as a property in your application delegate class.

Hope this helps.

Jim.