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@nvkiet
Last active June 21, 2023 12:35
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Switch root view controller
func switchRootViewController(rootViewController: UIViewController, animated: Bool, completion: (() -> Void)?) {
if animated {
UIView.transitionWithView(window, duration: 0.5, options: .TransitionCrossDissolve, animations: {
let oldState: Bool = UIView.areAnimationsEnabled()
UIView.setAnimationsEnabled(false)
self.window!.rootViewController = rootViewController
UIView.setAnimationsEnabled(oldState)
}, completion: { (finished: Bool) -> () in
if completion {
completion!()
}
})
} else {
window!.rootViewController = rootViewController
}
}
@ucotta
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ucotta commented Jun 5, 2017

Nice method!, thanks

@mitchins
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Works a treat

@abdelmajidrajad
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Very useful method, thank you

@omaralbeik
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Thanks, very useful :)

Here is a Swift 4 version

extension UIWindow {
	
	func switchRootViewController(_ viewController: UIViewController,  animated: Bool = true, duration: TimeInterval = 0.5, options: UIViewAnimationOptions = .transitionFlipFromRight, completion: (() -> Void)? = nil) {
		guard animated else {
			rootViewController = viewController
			return
		}
		
		UIView.transition(with: self, duration: duration, options: options, animations: {
			let oldState = UIView.areAnimationsEnabled
			UIView.setAnimationsEnabled(false)
			self.rootViewController = viewController
			UIView.setAnimationsEnabled(oldState)
		}) { _ in
			completion?()
		}
	}
}

@anirudhamahale
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One more variation, use this as global function.

func switchRootViewController(rootViewController: UIViewController, animated: Bool, completion: (() -> Void)?) {
    guard let window = UIApplication.shared.keyWindow else { return }
    if animated {
        UIView.transition(with: window, duration: 0.5, options: .transitionCrossDissolve, animations: {
            let oldState: Bool = UIView.areAnimationsEnabled
            UIView.setAnimationsEnabled(false)
            window.rootViewController = rootViewController
            UIView.setAnimationsEnabled(oldState)
        }, completion: { (finished: Bool) -> () in
            if (completion != nil) {
                completion!()
            }
        })
    } else {
        window.rootViewController = rootViewController
    }
}

@munepom
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munepom commented Mar 7, 2018

Nice work! Thanks!!! 🍎

@bfwg
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bfwg commented Jun 8, 2018

Make completion parameter optional.

    func switchRootViewController(rootViewController: UIViewController, animated: Bool, completion: (() -> Swift.Void)? = nil) {
      ...
    )

@piv199
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piv199 commented Oct 18, 2019

Warning: 'keyWindow' was deprecated in iOS 13.0: Should not be used for applications that support multiple scenes as it returns a key window across all connected scenes

@kpavankotesh
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What is the replacement for this? Any solution?

@bcmbf14
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bcmbf14 commented Feb 26, 2020

try this!

    let scene = UIApplication.shared.connectedScenes.first
    guard let windowScene = (scene as? UIWindowScene) else { return }
    let window = UIWindow(windowScene: windowScene)

@Bartozo
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Bartozo commented Mar 24, 2020

My solution is very simple. Inside your SceneDelegate.swift file add your function to update root view controller.
For example this is my function to change root widow to tab bar controller.

// SceneDelegate.swift

    func moveToTabBarController() {
        window?.rootViewController = createTabBar()
        window?.makeKeyAndVisible()
    }

And inside your view controller you can get access to scene delegate and call your change controller function.

   let sceneDelegate = self.view.window?.windowScene?.delegate as! SceneDelegate
   sceneDelegate.moveToTabBarController()

@AakifNadeem
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AakifNadeem commented Jul 31, 2020

If you have sceneDelegate in your project use this:

let sb = UIStoryboard(name: "Main", bundle: nil)
let VC = sb.instantiateViewController(withIdentifier: "LoginViewController") as! LoginViewController
let navRootView = UINavigationController(rootViewController: VC)
self.present(navRootView, animated: true, completion: nil)

@ahmedsafadii
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Swift 5.1

extension UIWindow {
    
    func switchRootViewController(_ viewController: UIViewController,
                                  animated: Bool = true,
                                  duration: TimeInterval = 0.5,
                                  options: AnimationOptions = .transitionFlipFromRight,
                                  completion: (() -> Void)? = nil) {
        guard animated else {
            rootViewController = viewController
            return
        }
        
        UIView.transition(with: self, duration: duration, options: options, animations: {
            let oldState = UIView.areAnimationsEnabled
            UIView.setAnimationsEnabled(false)
            self.rootViewController = viewController
            UIView.setAnimationsEnabled(oldState)
        }, completion: { _ in
            completion?()
        })
    }
    
}

@jesus003
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Swift 5.1

extension UIWindow {
    
    func switchRootViewController(_ viewController: UIViewController,
                                  animated: Bool = true,
                                  duration: TimeInterval = 0.5,
                                  options: AnimationOptions = .transitionFlipFromRight,
                                  completion: (() -> Void)? = nil) {
        guard animated else {
            rootViewController = viewController
            return
        }
        
        UIView.transition(with: self, duration: duration, options: options, animations: {
            let oldState = UIView.areAnimationsEnabled
            UIView.setAnimationsEnabled(false)
            self.rootViewController = viewController
            UIView.setAnimationsEnabled(oldState)
        }, completion: { _ in
            completion?()
        })
    }
    
}

how I can implement this ?

@lexuanquynh
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@jesus003
let loginVC = QGLoginViewController.loadFromNib()
guard let window = self.view.window else {
return
}
window.switchRootViewController(to: loginVC)

@joseph-elmallah
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joseph-elmallah commented Oct 14, 2021

Swift 5.5 with the introduction of async/await APIs

extension UIWindow {

    @MainActor
    func setRootViewController(_ newRootViewController: UIViewController, animated: Bool = true) async {
        guard animated else {
            rootViewController = newRootViewController
            return
        }

        await withCheckedContinuation({ (continuation: CheckedContinuation<Void, Never>) in
            UIView.transition(with: self, duration: 0.3, options: .transitionCrossDissolve) {
                let oldState: Bool = UIView.areAnimationsEnabled
                UIView.setAnimationsEnabled(false)
                self.rootViewController = newRootViewController
                UIView.setAnimationsEnabled(oldState)
            } completion: { _ in
                continuation.resume()
            }
        })
    }

}

@zzbhagyalakshmi
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Crash Occurrence in this method, not regular. Any Idea to fix this sporadic crash..

NSInternalInconsistencyException - Attempting to transfer an animation to an animation state that is not a direct child of the animation's animation state.

Fatal Exception: NSInternalInconsistencyException
0 CoreFoundation 0x92d1c __exceptionPreprocess
1 libobjc.A.dylib 0x14ee4 objc_exception_throw
2 Foundation 0x124c80 _userInfoForFileAndLine
3 UIKitCore 0x5f0658 -[UIViewAnimationState _transferAnimationToTrackingAnimator:]
4 UIKitCore 0x71ee0 __85+[UIViewPropertyAnimator _animationBlockForTrackingAnimation:animator:trackingSetup:]_block_invoke
5 UIKitCore 0x4a3d14 -[UIViewPropertyAnimator _runAnimations]
6 UIKitCore 0x34fba4 __49-[UIViewPropertyAnimator startAnimationAsPaused:]_block_invoke_2
7 UIKitCore 0x206ccc __49-[UIViewPropertyAnimator startAnimationAsPaused:]_block_invoke
8 UIKitCore 0x70754c __49-[UIViewPropertyAnimator startAnimationAsPaused:]_block_invoke.1011
9 UIKitCore 0x510eac -[UIViewPropertyAnimator _setupAnimationTracking:]
10 UIKitCore 0x9c494 -[UIViewPropertyAnimator startAnimationAsPaused:]
11 UIKitCore 0x3396e4 +[UIViewPropertyAnimator _trackAnimationWithAnimator:forLayer:forAnimationKey:trackingSetup:]
12 UIKitCore 0x9c07c +[UIViewPropertyAnimator _trackNonAdditiveAnimationWithAnimator:forLayer:forKey:]
13 UIKitCore 0x58d55c -[UIViewAnimationState pop]
14 UIKitCore 0x25bdb8 +[UIViewAnimationState popAnimationState]
15 UIKitCore 0x1751a8 +[UIView _setupAnimationWithDuration:delay:view:options:factory:animations:start:animationStateGenerator:completion:]

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