windows' was deprecated in iOS 15.0 creating Custom Alert [duplicate] - swift

Question

I'm using Core Data with Cloud Kit, and have therefore to check the iCloud user status during application startup. In case of problems I want to issue a dialog to the user, and I do it using UIApplication.shared.keyWindow?.rootViewController?.present(...) up to now.
In Xcode 11 beta 4, there is now a new deprecation message, telling me:
'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
How shall I present the dialog instead?

Answer 1

Edit The suggestion I make here is deprecated in iOS 15. So now what? Well, if an app doesn't have multiple windows of its own, I presume the accepted modern way would be to get the first of the app's connectedScenes, coerce to a UIWindowScene, and take its first window. But that is almost exactly what the accepted answer does! So my workaround feels rather feeble at this point. However, I'll let it stand for historical reasons.
The accepted answer, while ingenious, might be overly elaborate. You can get exactly the same result much more simply:
UIApplication.shared.windows.filter {$0.isKeyWindow}.first
I would also caution that the deprecation of keyWindow should not be taken overly seriously. The full warning message reads:
'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
So if you are not supporting multiple windows on iPad there is no objection to going ahead and continuing to use keyWindow.

Answer 2

iOS 16, compatible down to iOS 15
As this thread keeps getting traffic three years later, I want to share what I consider the most elegant solution with current functionality. It also works with SwiftUI.
UIApplication
.shared
.connectedScenes
.compactMap { ($0 as? UIWindowScene)?.keyWindow }
.first
iOS 15 and 16, compatible down to iOS 13
UIApplication
.shared
.connectedScenes
.flatMap { ($0 as? UIWindowScene)?.windows ?? [] }
.first { $0.isKeyWindow }
Note that connectedScenes is available only since iOS 13. If you need to support earlier versions of iOS, you have to place this in an if #available(iOS 13, *) statement.
A variant that is longer, but easier to understand:
UIApplication
.shared
.connectedScenes
.compactMap { $0 as? UIWindowScene }
.flatMap { $0.windows }
.first { $0.isKeyWindow }
iOS 13 and 14
The following historical answer is still valid on iOS 15, but should be replaced because UIApplication.shared.windows is deprecated. Thanks to #matt for pointing this out!
Original answer:
Improving slightly on matt's excellent answer, this is even simpler, shorter, and more elegant:
UIApplication.shared.windows.first { $0.isKeyWindow }

Answer 3

This is my solution:
let keyWindow = UIApplication.shared.connectedScenes
.filter({$0.activationState == .foregroundActive})
.compactMap({$0 as? UIWindowScene})
.first?.windows
.filter({$0.isKeyWindow}).first
Usage e.g.:
keyWindow?.endEditing(true)

Answer 4

Here is a backward-compatible way of detecting keyWindow:
extension UIWindow {
static var key: UIWindow? {
if #available(iOS 13, *) {
return UIApplication.shared.windows.first { $0.isKeyWindow }
} else {
return UIApplication.shared.keyWindow
}
}
}
Usage:
if let keyWindow = UIWindow.key {
// Do something
}

Answer 5

Usually use
Swift 5
UIApplication.shared.windows.filter {$0.isKeyWindow}.first
In addition，in the UIViewController:
self.view.window
view.window is current window for scenes
WWDC 2019:
Key Windows
Track windows manually
Introducing Multiple Windows on iPad - WWDC 2019 - Videos - Apple Developer
Supporting Multiple Windows on iPad | Apple Developer Documentation

Answer 6

For an Objective-C solution
+ (UIWindow *)keyWindow
{
NSArray<UIWindow *> *windows = [[UIApplication sharedApplication] windows];
for (UIWindow *window in windows) {
if (window.isKeyWindow) {
return window;
}
}
return nil;
}

Answer 7

A UIApplication extension:
extension UIApplication {
/// The app's key window taking into consideration apps that support multiple scenes.
var keyWindowInConnectedScenes: UIWindow? {
return windows.first(where: { $0.isKeyWindow })
}
}
Usage:
let myKeyWindow: UIWindow? = UIApplication.shared.keyWindowInConnectedScenes

Answer 8

Ideally, since it has been deprecated I would advice you to store the window in the SceneDelegate. However if you do want a temporary workaround, you can create a filter and retrieve the keyWindow just like this.
let window = UIApplication.shared.windows.filter {$0.isKeyWindow}.first

Answer 9

Supports iOS 13 and later.
To keep using similar syntax as the older iOS versions UIApplication.shared.keyWindow create this extension:
extension UIApplication {
var mainKeyWindow: UIWindow? {
get {
if #available(iOS 13, *) {
return connectedScenes
.flatMap { ($0 as? UIWindowScene)?.windows ?? [] }
.first { $0.isKeyWindow }
} else {
return keyWindow
}
}
}
}
Usage
if let keyWindow = UIApplication.shared.mainKeyWindow {
// Do Stuff
}

Answer 10

If you want to use it in any ViewController then you can simply use.
self.view.window

Answer 11

(Tested with iOS 15.2 running on Xcode 13.2.1)
extension UIApplication {
var keyWindow: UIWindow? {
// Get connected scenes
return UIApplication.shared.connectedScenes
// Keep only active scenes, onscreen and visible to the user
.filter { $0.activationState == .foregroundActive }
// Keep only the first `UIWindowScene`
.first(where: { $0 is UIWindowScene })
// Get its associated windows
.flatMap({ $0 as? UIWindowScene })?.windows
// Finally, keep only the key window
.first(where: \.isKeyWindow)
}
}
If you want to find the presented UIViewController in the key UIWindow , here is another extension you could find useful:
extension UIApplication {
var keyWindowPresentedController: UIViewController? {
var viewController = self.keyWindow?.rootViewController
// If root `UIViewController` is a `UITabBarController`
if let presentedController = viewController as? UITabBarController {
// Move to selected `UIViewController`
viewController = presentedController.selectedViewController
}
// Go deeper to find the last presented `UIViewController`
while let presentedController = viewController?.presentedViewController {
// If root `UIViewController` is a `UITabBarController`
if let presentedController = presentedController as? UITabBarController {
// Move to selected `UIViewController`
viewController = presentedController.selectedViewController
} else {
// Otherwise, go deeper
viewController = presentedController
}
}
return viewController
}
}
You can put this wherever you want, but I personally added it as an extension to UIViewController.
This allows me to add more useful extensions, like ones to present UIViewControllers more easily for example:
extension UIViewController {
func presentInKeyWindow(animated: Bool = true, completion: (() -> Void)? = nil) {
DispatchQueue.main.async {
UIApplication.shared.keyWindow?.rootViewController?
.present(self, animated: animated, completion: completion)
}
}
func presentInKeyWindowPresentedController(animated: Bool = true, completion: (() -> Void)? = nil) {
DispatchQueue.main.async {
UIApplication.shared.keyWindowPresentedController?
.present(self, animated: animated, completion: completion)
}
}
}

Answer 12

try with that:
UIApplication.shared.windows.filter { $0.isKeyWindow }.first?.rootViewController!.present(alert, animated: true, completion: nil)

Answer 13

As many of developers asking for Objective C code of this deprecation's replacement. You can use this below code to use the keyWindow.
+(UIWindow*)keyWindow {
UIWindow *windowRoot = nil;
NSArray *windows = [[UIApplication sharedApplication]windows];
for (UIWindow *window in windows) {
if (window.isKeyWindow) {
windowRoot = window;
break;
}
}
return windowRoot;
}
I created and added this method in the AppDelegate class as a class method and use it with very simple way that is below.
[AppDelegate keyWindow];
Don't forget to add this method in AppDelegate.h class like below.
+(UIWindow*)keyWindow;

Answer 14

For an Objective-C solution too
#implementation UIWindow (iOS13)
+ (UIWindow*) keyWindow {
NSPredicate *isKeyWindow = [NSPredicate predicateWithFormat:#"isKeyWindow == YES"];
return [[[UIApplication sharedApplication] windows] filteredArrayUsingPredicate:isKeyWindow].firstObject;
}
#end

Answer 15

Inspired by the answer of berni
let keyWindow = Array(UIApplication.shared.connectedScenes)
.compactMap { $0 as? UIWindowScene }
.flatMap { $0.windows }
.first(where: { $0.isKeyWindow })

Answer 16

I've solved with:
let scenes = UIApplication.shared.connectedScenes
let windowScene = scenes.first as? UIWindowScene
let window = windowScene?.windows.first

Answer 17

As you probably know, the key window is deprecated because of possible multiple scenes. The most convenient solution is to provide a currentWindow as an extension, then search-and-replace.
extension UIApplication {
var currentWindow: UIWindow? {
connectedScenes
.compactMap { $0 as? UIWindowScene }
.flatMap { $0.windows }
.first { $0.isKeyWindow }
}
}

Answer 18

NSSet *connectedScenes = [UIApplication sharedApplication].connectedScenes;
for (UIScene *scene in connectedScenes) {
if (scene.activationState == UISceneActivationStateForegroundActive && [scene isKindOfClass:[UIWindowScene class]]) {
UIWindowScene *windowScene = (UIWindowScene *)scene;
for (UIWindow *window in windowScene.windows) {
UIViewController *viewController = window.rootViewController;
// Get the instance of your view controller
if ([viewController isKindOfClass:[YOUR_VIEW_CONTROLLER class]]) {
// Your code here...
break;
}
}
}
}

Answer 19

Berni's code is nice but it doesn't work when the app comes back from background.
This is my code:
class var safeArea : UIEdgeInsets
{
if #available(iOS 13, *) {
var keyWindow = UIApplication.shared.connectedScenes
.filter({$0.activationState == .foregroundActive})
.map({$0 as? UIWindowScene})
.compactMap({$0})
.first?.windows
.filter({$0.isKeyWindow}).first
// <FIX> the above code doesn't work if the app comes back from background!
if (keyWindow == nil) {
keyWindow = UIApplication.shared.windows.first { $0.isKeyWindow }
}
return keyWindow?.safeAreaInsets ?? UIEdgeInsets()
}
else {
guard let keyWindow = UIApplication.shared.keyWindow else { return UIEdgeInsets() }
return keyWindow.safeAreaInsets
}
}

Answer 20

- (UIWindow *)mainWindow {
NSEnumerator *frontToBackWindows = [UIApplication.sharedApplication.windows reverseObjectEnumerator];
for (UIWindow *window in frontToBackWindows) {
BOOL windowOnMainScreen = window.screen == UIScreen.mainScreen;
BOOL windowIsVisible = !window.hidden && window.alpha > 0;
BOOL windowLevelSupported = (window.windowLevel >= UIWindowLevelNormal);
BOOL windowKeyWindow = window.isKeyWindow;
if(windowOnMainScreen && windowIsVisible && windowLevelSupported && windowKeyWindow) {
return window;
}
}
return nil;
}

Answer 21

I faced the issue when .foregroundActive scenes were empty
So here is my workaround
public extension UIWindow {
#objc
static var main: UIWindow {
// Here we sort all the scenes in order to work around the case
// when no .foregroundActive scenes available and we need to look through
// all connectedScenes in order to find the most suitable one
let connectedScenes = UIApplication.shared.connectedScenes
.sorted { lhs, rhs in
let lhs = lhs.activationState
let rhs = rhs.activationState
switch lhs {
case .foregroundActive:
return true
case .foregroundInactive:
return rhs == .background || rhs == .unattached
case .background:
return rhs == .unattached
case .unattached:
return false
#unknown default:
return false
}
}
.compactMap { $0 as? UIWindowScene }
guard connectedScenes.isEmpty == false else {
fatalError("Connected scenes is empty")
}
let mainWindow = connectedScenes
.flatMap { $0.windows }
.first(where: \.isKeyWindow)
guard let window = mainWindow else {
fatalError("Couldn't get main window")
}
return window
}
}

Answer 22

If your app has not been updated to adopt the Scene based app lifecycle, another simple way to get the active window object is via UIApplicationDelegate:
let window = UIApplication.shared.delegate?.window
let rootViewController = window??.rootViewController

Answer 23

if you're using SwiftLint with 'first_where' rule and wanna to silence warring:
UIApplication.shared.windows.first(where: { $0.isKeyWindow })

Answer 24

An Objective C solution:
UIWindow *foundWindow = nil;
NSSet *scenes=[[UIApplication sharedApplication] connectedScenes];
NSArray *windows;
for(id aScene in scenes){ // it's an NSSet so you can't use the first object
windows=[aScene windows];
if([aScene activationState]==UISceneActivationStateForegroundActive)
break;
}
for (UIWindow *window in windows) {
if (window.isKeyWindow) {
foundWindow = window;
break;
}
}
// and to find the parent viewController:
UIViewController* parentController = foundWindow.rootViewController;
while( parentController.presentedViewController &&
parentController != parentController.presentedViewController ){
parentController = parentController.presentedViewController;
}

Answer 25

My solution is the following, works in iOS 15
let window = (UIApplication.shared.connectedScenes.first as? UIWindowScene)?.windows.first

Answer 26

I alloc'ed a newWindow for a view, and set it [newWindow makeKeyAndVisible];
When finished using it, set it [newWindow resignKeyWindow];
and then try to show the original key-window directly by [UIApplication sharedApplication].keyWindow.
Everything is all right on iOS 12, but on iOS 13 the original key-window can't been normal shown. It shows a whole white screen.
I solved this problem by:
UIWindow *mainWindow = nil;
if ( #available(iOS 13.0, *) ) {
mainWindow = [UIApplication sharedApplication].windows.firstObject;
[mainWindow makeKeyWindow];
} else {
mainWindow = [UIApplication sharedApplication].keyWindow;
}

Answer 27

For iOS 16, I used the following:
let keyWindow = UIApplication.shared.currentUIWindow()?.windowScene?.keyWindow