Accessing AppDelegate window from viewController [closed]

Question

I make walkthrough (onboarding flow) in my app and I'd like to have a skip button. The button is located on viewController, so I figured out that the best way to move to another viewController would be access app delegate window.

However, it keeps getting me an error that AppDelegate.Type does not have a member called "window".

@IBAction func skipWalkthrough(sender: AnyObject) { let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate AppDelegate.window!.rootViewController = RootViewController }

Is there anything wrong with such approach?

You can also try to get visible viewcontroller

Yogesh Patel
– Yogesh Patel

2019-05-31 18:44:59 +00:00
Commented May 31, 2019 at 18:44 — Yogesh Patel
– Yogesh Patel, Commented May 31, 2019 at 18:44

OurangZeb Khan · Accepted Answer · 2018-09-01 19:19:31Z

57

You have a typo it is supposed to be appDelegate not AppDelegate. So like this:

@IBAction func skipWalkthrough(sender: AnyObject) { let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate appDelegate.window!.rootViewController = RootViewController }

Swift 3.2

@IBAction func skipWalkthrough(_ sender: AnyObject) { let appDelegate = UIApplication.shared.delegate as! AppDelegate appDelegate.window!.rootViewController = controller }

edited Sep 1, 2018 at 19:19

OurangZeb Khan

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answered May 4, 2015 at 10:32

Stefan Salatic

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3 Comments

theDC Over a year ago

Ok right, what a studip mistake! Btw, now there is a problem with RootViewController, how to access this view controller which is declared in storyboard? I guess making a new instance isn't a good idea? I mean RootViewController() leads to black screen, so should be another wait to access such controller

Stefan Salatic Over a year ago

Here is how I do it in my code let storyboardId = "LoginStoryboardIdentifier"

self.window?.rootViewController = self.window?.rootViewController?.storyboard?.instantiateViewControllerWithIdentifier(storyboardId) as? UIViewController

Talha Ahmad Khan Over a year ago

Works perfectly but while noticing memory consumption, I see no memory decrease when I replace the Root View controller (a) with (b). It means (a) has not wiped out from the memory, right? How to wipe it out from memory 1st and then show (b) controller

Roman Podymov · Accepted Answer · 2019-07-26 13:08:46Z

This is for with or without Storyboard and it is working for Swift 3+

let appDelegate = UIApplication.shared.delegate as? AppDelegate let mainStoryboard = UIStoryboard(name: "Main", bundle: nil) let homeController = mainStoryboard.instantiateViewController(withIdentifier: "HomeViewController") as! HomeViewController appDelegate?.window?.rootViewController = homeController

Does this still work in Swift 5+, I can't seem to get this to work, the line appDelegate?.window throws an error saying cannot use optional chaining on non-optional value of type 'any', fixing it gives other errors.

Ted Lowery · Accepted Answer · 2016-12-27 22:48:49Z

11

Swift 3

This is a better way:

 if let window = NSApplication.shared().windows.first { window.acceptsMouseMovedEvents = true; }

answered Dec 27, 2016 at 22:48

Ted Lowery

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1 Comment

Yogesh Patel Over a year ago

NSApplication is use in MacOS this question is tag in iOS

Nikunj Kumbhani · Accepted Answer · 2021-06-02 11:50:19Z

appDelegate.window!.rootViewController is not working in Swift 5

Here is working code

Add below extension

extension UIWindow { static var key: UIWindow! { if #available(iOS 13, *) { return UIApplication.shared.windows.first { $0.isKeyWindow } } else { return UIApplication.shared.keyWindow } } }

use

let mainSB = UIStoryboard(name: "Main", bundle: nil) if let RootVc = mainSB.instantiateViewController(withIdentifier: "NavigationController") as? UINavigationController{ UIWindow.key.rootViewController = RootVc } UIWindow.key // to access only window

This is how you access instance of UIWindow in Swift5 , iOS 13 & above versions to set it's rootViewController or to present any UIView. Thanks mate.
@Suhail I forgot 1 line to Add window.makeKeyAndVisible() Please check my Updated Answer it will sure work :)

Gustavo Vollbrecht · Accepted Answer · 2019-06-05 13:51:24Z

You can also use conditional binding to reach the window.

if let window = UIApplication.shared.windows.first { // use window here. }

giorashc · Accepted Answer · 2015-05-04 10:32:32Z

You are using the protocol name (i.e. AppDelegate) instead of the instance:

Should be:

appDelegate.window!.rootViewController = RootViewController

Umit Kaya · Accepted Answer · 2019-05-31 16:45:56Z

You can access tab bar anywhere from the app. Use below:

let appDelegate = UIApplication.shared.delegate as! AppDelegate if let tabBarController = appDelegate.window!.rootViewController as? UITabBarController { if let tabItems = tabBarController.tabBar.items { let tabItem = tabItems[2] tabItem.badgeValue = "5" //enter any value } }

iGatiTech · Accepted Answer · 2020-02-05 18:10:57Z

1

This solution work for : After Login / Register Programmatically add UITabbarController

let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate appDelegate.window!.rootViewController = tabs appDelegate.window!.makeKeyAndVisible()

edited Feb 5, 2020 at 18:10

iGatiTech

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answered Feb 16, 2017 at 11:55

Humza Shahid

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1 Comment

Toby Speight Over a year ago

Whilst this code snippet is welcome, and may provide some help, it would be greatly improved if it included an explanation of how and why this solves the problem. Remember that you are answering the question for readers in the future, not just the person asking now! Please edit your answer to add explanation, and give an indication of what limitations and assumptions apply.

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