How to use my @EnvironmentObject in AppDelegate in SwiftUi (iOS 15 / Xcode 13.2.1)?

Question

I have a class :

class AppInfos_M: ObservableObject {
    @Published var currentUser: User_M = User_M()
    @Published var userTo: User_M = User_M()
}

I declare it in main and pass in to my view with environmentObject:

...

@main
struct TestApp: App {
    @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
    
...

    @StateObject var appInfos_M = AppInfos_M()
    
    var body: some Scene {
        WindowGroup {
            LaunchScreen_V()
                .environmentObject(appInfos_M)
...
 
        }
    }
}

The class works very good in my app. Now I need to modify it from AppDelegate, because I need to get appInfos_M.userTo.id when I get a notification. I tried several things, but none works. How can I access it?

In all my views where I need it, I declare this way and it works fine, but not in AppDelegate, why?:

 @EnvironmentObject var appInfos_M: AppInfos_M

Here is one of the tests I tried that did not work:

...

class AppDelegate: NSObject, UIApplicationDelegate { ... }

...

@available(iOS 10, *)
extension AppDelegate : UNUserNotificationCenterDelegate {

...

func userNotificationCenter(_ center: UNUserNotificationCenter,
                                didReceive response: UNNotificationResponse,
                                withCompletionHandler completionHandler: @escaping () -> Void) {

@EnvironmentObject var appInfos_M: AppInfos_M

 let userInfo = response.notification.request.content.userInfo

appInfos_M.userTo.id = "just for testing here" // <- i get this error : Thread 1: Fatal error: No ObservableObject of type AppInfos_M found. A View.environmentObject(_:) for AppInfos_M may be missing as an ancestor of this view.

...

Note that 3 small dots ... replace any code that is useless here.

Does this answer your question stackoverflow.com/a/64484944/12299030? — Asperi
– Asperi, Commented Jan 22, 2022 at 18:34
You can't access the environment from your app delegate; the environment is only available from the view hierarchy. You can simply create a property in your app delegate adapter and assign your value to it — Paulw11
– Paulw11, Commented Jan 22, 2022 at 21:05

cluelessCoder · Accepted Answer · 2022-01-23 14:30:08Z

7

You can always store AppInfos_M in your AppDelegate Like this

class AppDelegate: NSObject, UIApplicationDelegate {
    var appInfos = AppInfos_M()
    (...)
}

You can then use it as EnvironmentObject as:

...
@main
struct TestApp: App {
    @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
    
...
    
    var body: some Scene {
        WindowGroup {
            LaunchScreen_V()
                .environmentObject(appDelegate.appInfos)
...
 
        }
    }
}

answered Jan 23, 2022 at 14:30

cluelessCoder

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3 Comments

lcj Over a year ago

This should be marked as the answer. It worked for me w/out having to use a singleton as many of the other posts did.

sebasira Over a year ago

I was about to refactor my code to use a singleton, until I found this! Perfect solution! Why some basic stuff has to be so complicated or overlooked in SwiftUI?

cluelessCoder Over a year ago

Happy to help :-) I definitely struggled with these things when I started doing iOS development in SwifUI without prior UIKit knowledge

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