SwiftUI 中的状态变量未选取 UserDefaults .set

Question

I am attempting to to detect whether a user has onboarded or not eg launched the app. When I access the UserDefaults.standard.bool directly I can see the change but when I attempt to access it through the @State it retains the original false value.

As a workaround I directly change the value to true , but I have a feeling this isn't the way to do this.

How can I get the @State variable to pick up the change when changing the UserDefaults object without having to close and restart the app? I want the user to onboard, click a button, then switch immediately to the main app view.

@State var userOnboarded: Bool = UserDefaults.standard.bool(forKey: "userOnboarded")
    
    var body: some Scene {
        WindowGroup {
            if userOnboarded {
                Text("PLACEHOLDER: Main App View")
            } else {
                Button(action: {
                    UserDefaults.standard.set(true, forKey: "userOnboarded")
                    userOnboarded = true
                    print(UserDefaults.standard.bool(forKey: "userOnboarded"))
                }) {
                    VStack {
                        Text("Click circle to onboard.")
                        Circle()
                            .foregroundColor(Color.red)
                    }
                }
            }
        }

Answer 1

In SwiftUI there is a dedicated wrapper to watch UserDefaults. As previously mentioned in your comments, it's called @AppStorage and it's used like so.

@AppStorage("userOnboarded") var userOnboarded: Bool = false

It functions similarly to a UserDefault but will refresh the view and set the data when the value changes.

Button(action: {
    userOnboarded = true
    print(UserDefaults.standard.bool(forKey: "userOnboarded"))
}) //....

Notice in the button, we set the userOnboarded to true, this will update and refresh your view as well as update the user default value.