ios - SwiftUI:如何以编程方式更改 rootview Controller

Question

我试图在用户注销后将 rootview Controller 更改为不同的屏幕。

    if let window = UIApplication.shared.windows.first {
        window.rootViewController = UIHostingController(rootView: SignInView())
        window.endEditing(true)

        window.makeKeyAndVisible()
    }

这就是我到目前为止所拥有的。它导航到不同的 View ，但它使新 View 上的按钮无法使用。有没有更好的方法来改变 rootview 或者我错过了什么？

Answer 1

我的方法是创建一个可观察的对象来协调各种应用程序 View 之间的导航。下面一个简化的例子给你一个想法:

//Your app views
enum AppViews {
    case LoginView
    case MainAppView
}

//Class that conforms to the ObservableObject protocol and publishes the viewId property.
//Basically your navigation will react to viewId changes

class ShowingView: ObservableObject {
    
    init(showingView: AppViews) {
        self.viewId = showingView
    }
    
    @Published var viewId : AppViews
}

//The current root view of your app is observing changes of the ShowingView class and switch between your app views
struct AppRootView: View {
    
    @ObservedObject var showingView: ShowingView
    
    var body: some View {
        Group {
            if showingView.viewId == .LoginView {
                TermsAndConditionsView()
                    .environmentObject(showingView)
            }
            else {
                MainAppView()
                    .environmentObject(showingView)
            }
        }
    }
}

请注意，您可以通过 showingView作为 environmentObject 到您的 View ，并在需要时使用它切换到另一个 View 。在您的情况下，当用户注销时切换到另一个屏幕。
在您的 现场委托(delegate)然后，您可以例如在登录和主视图之间切换，如下所示

var appStartView: AppViews

let isloggedIn = UserDefaults.standard.bool(forKey: "IsLoggedIn")

if isLoggedIn == false {
    appStartView = .LoginView
}
else {
    appStartView = .MainAppView
}

let contentView = AppRootView(showingView: ShowingView(showingView: appStartView))

if let windowScene = scene as? UIWindowScene {
    let window = UIWindow(windowScene: windowScene)
    window.rootViewController = UIHostingController(rootView: contentView)
    self.window = window
    window.makeKeyAndVisible()
}

在 MainAppView 之间切换和 LoginView您可以简单地修改 environmentObject showingView 的值

self.showingView.viewId = AppViews.LoginView

我希望它有助于指导您朝着正确的方向前进