makeKeyAndVisible doesn't work?

Question

I've been using this code to create simple apps for years, but it is suddenly not working anymore with iOS 13 and Xcode 11. When I run the app I just get a blank screen. What am I doing wrong?

  var window: UIWindow?

  func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool
  {
  window = UIWindow(frame: UIScreen.main.bounds)
  window?.rootViewController = UINavigationController(rootViewController: HomeViewController())
  window?.makeKeyAndVisible()
  return true
  }

UIKit

5.1k

Posted by

flarosa

Reply

Add a Comment

Answer 1

Have you checked if you have a sceneDelegate file ?

If so, you need to add an entry in your infos.plist:

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">

<dict>

<key>UIApplicationSupportsMultipleScenes</key>

<key>UISceneConfigurations</key>

<dict>

<key>UIWindowSceneSessionRoleApplication</key>

<array>

<dict>

<key>UISceneConfigurationName</key>

<string>Default Configuration</string>

<key>UISceneDelegateClassName</key>

<string>$(PRODUCT_MODULE_NAME).SceneDelegate</string>

<key>UISceneStoryboardFile</key>

</dict>

</array>

</dict>

</plist>

Why do you need to create the window ?

In my apps, view is created in IB and I do not need to call window nor set it key and visible.

Posted by

Claude31

Add a Comment

Answer 2

Thanks, I did have a scene delegate, and removing it fixed the issue.

I guess a scene delegate is something new that Xcode gives you by default. I had never even heard of a Scene before.

Posted by

flarosa

Add a Comment

Answer 3

Thanks for the feedback, glad for you it works. And don't forget to close the thread.

To answer your last question: Scenes are effectively new.

Note that scenes will become compulsory for any iPad app as soon as april 2020.

There is a good WWDC 2019 session (258 I think) about it.

In fact, adopting scene management, even on an existing project is very easy:

- create the sceneDelegate.swift

- you can keep the appdelegate functions as is ; they will be ignored on IOS 13, except appDidFinishLaunching

- In the sceneDelegate, declare all func with @available(iOS 13.0, *)

- transfer the content of appDelegate func (such as didBecomeActive) to their equivalent in SceneDelegate

- add the infos.plist section (you can copy and paste the whole section from a void project you create)

- don't forget to set the VC presentation to fullScreen instead of Automatic (otherwise, strange small size views on iPad).

And that's it.

Posted by

Claude31

Add a Comment

makeKeyAndVisible doesn't work?

Replies