Implement dark mode switch in SwiftUI App

问题

I'm currently looking into Dark Mode in my App. While Dark Mode itself isn't much of a struggle because of my SwiftUI basis i'm struggling with the option to set the ColorScheme independent of the system ColorScheme.

I found this in apples human interface guidelines and i'd like to implement this feature. (Link: Human Interface Guidelines)

Any idea how to do this in SwiftUI? I found some hints towards @Environment but no further information on this topic. (Link: Last paragraph)

回答1:

First you need to access the window to change the app colorScheme that called UserInterfaceStyle in UIKit.

I used this in SceneDelegate:

private(set) static var shared: SceneDelegate?

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
    Self.shared = self
    ,,,
}

Then you need to bind an action to the toggle. So you need a model for it.

struct ToggleModel {
    var isDark: Bool = true {
        didSet { SceneDelegate.shared?.window!.overrideUserInterfaceStyle = isDark ? .dark : .light }
    }
}

At last, you just need to toggle the switch:

struct ContentView: View {
     @State var model = ToggleModel()

     var body: some View {
         Toggle(isOn: $model.isDark) {
             Text("is Dark")
        }
    }
}

来源：https://stackoverflow.com/questions/58476048/implement-dark-mode-switch-in-swiftui-app