UIViewController.View.Window is null in ViewDidLoad method

Question

Regardless on which controller type (UIViewController, UITableViewController), the following line always yields null in the ViewDidLoad method:

this.View.Window

Is this behavior normal, or am I doing something odd? What could lead to UIViewController.View.Window being null?

(I suppose this question concerns not only MonoTouch, but also 'normal' Objective-C Cocoa).

(MonoTouch 5.2.11, Xcode 4.2.1 4D502)

score 35 · Accepted Answer · answered Apr 23 '12 at 09:52

35

According to the documentation of UIView, the window property is nil if the view has not yet been added to a window which is the case when viewDidLoad is called.

answered Apr 23 '12 at 09:52

sch

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2

What method is called after the view is added to a window? – Alex Ryan Jan 28 '15 at 21:48
12

@AlexRyan You can use `-viewDidAppear`. – Renfei Song Apr 30 '15 at 13:07

score 7 · Answer 2 · edited Mar 31 '20 at 08:36

7

self.view.window will be available in viewDidAppear:

override func viewDidAppear(_ animated: Bool) {
    print(self.view.window)
    let vc = self.storyboard?.instantiateViewController(identifier: "SecondViewController") as? SecondViewController
    self.view.window?.rootViewController = vc
}

edited Mar 31 '20 at 08:36

pkamb

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answered Jan 17 '20 at 12:40

dinesh sharma

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score 5 · Answer 3 · edited Jun 29 '18 at 09:53

5

Instead of self.view.window use

[(YourAppDelegate *)[[UIApplication sharedApplication] delegate] window]

edited Jun 29 '18 at 09:53

Sangram Shivankar

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answered Oct 23 '13 at 17:02

cprcrack

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It's a problem if you are using `UIScene`. – Pedro Paulo Amorim Jan 15 '20 at 19:08

UIViewController.View.Window is null in ViewDidLoad method

3 Answers3

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