ios - 如何更改 SceneDelegate 中的 @ObservedObject 变量？

Question

我这里有一个模型:

class Instance: ObservableObject {
    @Published var status: Status = .offline

它会在更改时更新以下 View ...

struct HomeView: View {
    @ObservedObject var instance = Instance()
    var body: some View {
        Text(self.instance.status.text)
    }
}

我想更改 status 的值当我的应用程序打开时。例如，在 SceneDelegate :

class SceneDelegate: UIResponder, UIWindowSceneDelegate {
    
    var window: UIWindow?

    func sceneWillEnterForeground(_ scene: UIScene) {
        // Change Instance variable status to .online
    }

我怎样才能做到这一点？
编辑:

struct ContentView: View {
    @ObservedObject var auth = UserAuth()
    var body: some View {
        Group {
            if auth.uid != nil { HomeView(auth: auth) } else { LoginView(auth: auth) }
        }
    }
}

Answer 1

您可以简单地将您的实例移动到您的 SceneDelegate 并将引用传递给您的 HomeView。您可以根据需要将其直接传递或将您的实例放入环境中。下面是直接引用的示例:

class SceneDelegate: UIResponder, UIWindowSceneDelegate {

    var window: UIWindow?
    var instance = Instance()
    ...

    let contentView = HomeView(instance: self.instance)

    ...
    func sceneWillEnterForeground(_ scene: UIScene) {
        instance.status = ...
    }
    ...

更改您的 View ，使其不会自行初始化 Instance:

struct HomeView: View {
    @ObservedObject var instance: Instance
    var body: some View {
        Text(self.instance.status.text)
    }
}