以编程方式导航到SwiftUI中的新视图

成功登录后,可以用登录视图替换下一个视图。例如:

struct LoginView: View {
    var body: some View {
        ...
    }
}

struct NextView: View {
    var body: some View {
        ...
    }
}

// Your starting view
struct ContentView: View {

    @EnvironmentObject var userAuth: UserAuth 

    var body: some View {
        if !userAuth.isLoggedin {
            LoginView()
        } else {
            NextView()
        }

    }
}

您应该在数据模型中处理登录过程,并使用绑定,例如 @EnvironmentObject isLoggedin 同意你的观点。

注: 版本11.0 beta 4 ,以符合协议 “BindableObject” 这个 willChange 必须添加属性

import Combine

class UserAuth: ObservableObject {

  let didChange = PassthroughSubject<UserAuth,Never>()

  // required to conform to protocol 'ObservableObject' 
  let willChange = PassthroughSubject<UserAuth,Never>()

  func login() {
    // login request... on success:
    self.isLoggedin = true
  }

  var isLoggedin = false {
    didSet {
      didChange.send(self)
    }

    // willSet {
    //       willChange.send(self)
    // }
  }
}

struct ContentView: View {

    @EnvironmentObject var userAuth: UserAuth 

    var body: some View {
        if !userAuth.isLoggedin {
            return AnyView(LoginView())
        } else {
            return AnyView(NextView())
        }

    }
}

这是与Xcode 11.4和Swift 5一起使用的

struct LoginView: View {
    
    @State var isActive = false
    @State var attemptingLogin = false
    
    var body: some View {
        ZStack {
            NavigationLink(destination: HomePage(), isActive: $isActive) {
                Button(action: {
                    attlempinglogin = true
                    // Your login function will most likely have a closure in 
                    // which you change the state of isActive to true in order 
                    // to trigger a transition
                    loginFunction() { response in
                        if response == .success {
                            self.isActive = true
                        } else {
                            self.attemptingLogin = false
                        }
                    }
                }) {
                    Text("login")
                }
            }
            
            WaitingIndicator()
                .opacity(attemptingLogin ? 1.0 : 0.0)
        }
    }
}

将导航链接与$isActive绑定变量一起使用

根据截至的联合收割机上的更改,阐述其他人已阐述的内容 Swift Version 5.2

1. 创建一个类名 UserAuth 如下所示,不要忘记导入 import Combine

class UserAuth: ObservableObject {
        @Published var isLoggedin:Bool = false

        func login() {
            self.isLoggedin = true
        }
    }

2. 使现代化 SceneDelegate.Swift 具有

   let contentView = ContentView().environmentObject(UserAuth())

3. 您的身份验证视图

    struct LoginView: View {
       @EnvironmentObject  var  userAuth: UserAuth
       var body: some View {
           ...
       if ... {
       self.userAuth.login()
       } else {
       ...
       }
    }
   }
   
   

4. 验证成功后,如果验证失败 userAuth.isLoggedin = true 然后它将被加载。

      struct NextView: View {
        var body: some View {
        ...
        }
      }
   

struct ContentView: View {
    @EnvironmentObject var userAuth: UserAuth 
    var body: some View {
        if !userAuth.isLoggedin {
                LoginView()
            } else {
                NextView()
            }
    }
  }

这是电话的分机 UINavigationController NavigationLink isActive 绑定是正确的方法,但它既不灵活也不可扩展。下面的扩展为我做了一个技巧:

/**
 * Since SwiftUI doesn't have a scalable programmatic navigation, this could be used as
 * replacement. It just adds push/pop methods that host SwiftUI views in UIHostingController.
 */
extension UINavigationController: UINavigationControllerDelegate {

    convenience init(rootView: AnyView) {
        let hostingView = UIHostingController(rootView: rootView)
        self.init(rootViewController: hostingView)

        // Doing this to hide the nav bar since I am expecting SwiftUI
        // views to be wrapped in NavigationViews in case they need nav.
        self.delegate = self
    }

    public func pushView(view:AnyView) {
        let hostingView = UIHostingController(rootView: view)
        self.pushViewController(hostingView, animated: true)
    }

    public func popView() {
        self.popViewController(animated: true)
    }

    public func navigationController(_ navigationController: UINavigationController, willShow viewController: UIViewController, animated: Bool) {
        navigationController.navigationBar.isHidden = true
    }
}

下面是一个简单的例子,使用这个 window.rootViewController

var appNavigationController = UINavigationController.init(rootView: rootView)
window.rootViewController = appNavigationController
window.makeKeyAndVisible()

// Now you can use appNavigationController like any UINavigationController, but with SwiftUI views i.e. 
appNavigationController.pushView(view: AnyView(MySwiftUILoginView()))

我遵循了Gene的答案,但我在下面解决了两个问题。首先,变量isLoggedIn必须具有属性@Published才能按预期工作。第二个问题是如何实际使用环境对象。

@Published var isLoggedin = false {
didSet {
  didChange.send(self)
}

第二个问题是如何实际使用环境对象。吉恩的回答并不是真的错,我只是注意到评论中有很多关于它的问题,我没有足够的因果报应来回应它们。将此添加到ScenedLegate视图:

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
    // Use this method to optionally configure and attach the UIWindow `window` to the provided UIWindowScene `scene`.
    // If using a storyboard, the `window` property will automatically be initialized and attached to the scene.
    // This delegate does not imply the connecting scene or session are new (see `application:configurationForConnectingSceneSession` instead).
    var userAuth = UserAuth()
    
    // Create the SwiftUI view that provides the window contents.
    let contentView = ContentView().environmentObject(userAuth)

现在,您只需创建要导航到的新视图的实例,并将其放入NavigationButton:

NavigationButton(destination: NextView(), isDetail: true, onTrigger: { () -> Bool in
    return self.done
}) {
    Text("Login")
}

如果返回true,则表示您已成功登录用户。