How do you access & edit an @AppStorage var from multiple other views in SwiftUI 2.0?

问题

Is there a better way to do this? Is there a way to access the UserDefaults in the environment?? I did the following:

struct ContentView: View {
    @AppStorage("darkMode") var darkMode = false

    var body: some View {
            SubView(darkMode: $darkMode)
        }
    }
}

struct SubView: View {
    @Binding var darkMode: Bool
    var body: some View {
        Text("Dark Mode is \(darkMode == true ? "on" : "off")")
    }
}

回答1:

By using @AppStorage in different views you still access the same UserDefaults.standard storage (unless you explicitly specify the suiteName).

Which means you can just use the @AppStorage directly in the subview.

struct ContentView: View {
    @AppStorage("darkMode") var darkMode = DefaultSettings.darkMode

    var body: some View {
        VStack {
            Button("Toggle dark mode") {
                self.darkMode.toggle()
            }
            SubView()
        }
        .colorScheme(darkMode ? .dark : .light)
        .preferredColorScheme(darkMode ? .dark : .light)
    }
}

struct SubView: View {
    @AppStorage("darkMode") var darkMode = DefaultSettings.darkMode

    var body: some View {
        Text("Dark Mode is \(darkMode == true ? "on" : "off")")
    }
}

enum DefaultSettings {
    static let darkMode = false
}

Note: the default darkMode value is extracted (to the DefaultSettings enum) so you don't repeat false in each view.

---

Alternatively you can inject @AppStorage directly to the environment. See:

• Can @AppStorage be used in the Environment in SwiftUI?

来源：https://stackoverflow.com/questions/64117138/how-do-you-access-edit-an-appstorage-var-from-multiple-other-views-in-swiftui