The app delegate must implement the window property if it wants to use a main storyboard file swift

Question

I have just developed an app, but when running in the simulator the debugger console says:

The app delegate must implement the window property if it w

Answer 1

Make sure you have the following property declaration in your AppDelegate class:

var window: UIWindow?

Answer 2

Add the following window declaration in Appdelegate file

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    
    var window:UIWindow?
    ...

Implementation of this property is required if your app’s Info.plist file contains the UIMainStoryboardFile key. The default value of this synthesized property is nil, which causes the app to create a generic UIWindow object and assign it to the property. If you want to provide a custom window for your app, you must implement the getter method of this property and use it to create and return your custom window.

Answer 3

Setting in Info.plist Application Scene Manifest > Enable Mutliple Windows > false. This solved the problem for me.

Answer 4

Swift 5 & Xcode 11

Make sure that SceneDelegate contains UIWindow property

class SceneDelegate: UIResponder, UIWindowSceneDelegate {

    var window: UIWindow?

    //...
}