SwiftUI - Firebase 身份验证 - 环境对象不会在登录时更新

Question

我按照本教程将 Firebase 用户身份验证添加到我的 SwiftUI 项目中。当用户登录或注册时，登录视图应该消失，而应该出现显示“登录成功”的文本。然而，这不会发生。登录/注册过程似乎有效，但视图没有改变，我怀疑EnvironmentalObject. 有没有人对为什么会发生这种情况有一些想法？谢谢！

这是我的一些代码 -

AppDelegate.swift

...
func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
    if let windowScene = scene as? UIWindowScene {
        let window = UIWindow(windowScene: windowScene)
        window.rootViewController = UIHostingController(rootView: ContentView().environmentObject(SessionStore()))
        self.window = window
        window.makeKeyAndVisible()
    }
}
...

内容视图.swift

import SwiftUI

struct ContentView : View {

  @EnvironmentObject var session: SessionStore

  func getUser () {
      session.listen()
  }

  var body: some View {
      VStack {
          if (session.session == nil) {
              SignInView()
          } else {
              Text("Login successful!")
          }
    }.onAppear {
        self.getUser()
    }
  }
} 

登录视图.swift

import SwiftUI

struct SignInView : View {

    @State var email: String = ""
    @State var password: String = ""
    @State var loading = false
    @State var error = false

    @State var signInWorked = ""

    @EnvironmentObject var session: SessionStore

    func signIn () {
        loading = true
        error = false
        session.signIn(email: email, password: password) { (result, error) in
            self.loading = false
            if error != nil {
                self.error = true
            } else {
                self.email = ""
                self.password = ""
                self.signInWorked = "Signed In!"
            }
        }
    }

    func signUp () {
        loading = true
        error = false
        session.signUp(email: email, password: password) { (result, error) in
            self.loading = false
            if error != nil {
                self.error = true
            } else {
                self.email = ""
                self.password = ""
                self.signInWorked = "Signed In!"
            }
        }
    }

    var body: some View {
        VStack {
            TextField("Email Adress", text: $email)
            SecureField("Password", text: $password)
            if (error) {
                Text("ahhh crap")
            }
            Button(action: signIn) {
                Text("Sign in")
            }
            Button(action: signUp) {
               Text("Sign Up")
            }
            Text(signInWorked)
        }
    }
}

SessionStore.swift

import SwiftUI
import Firebase
import Combine

class SessionStore : ObservableObject {
var didChange = PassthroughSubject<SessionStore, Never>()
var session: User? { didSet { self.didChange.send(self) }}
var handle: AuthStateDidChangeListenerHandle?

func listen () {
    // monitor authentication changes using firebase
    handle = Auth.auth().addStateDidChangeListener { (auth, user) in
        if let user = user {
            // if we have a user, create a new user model
            print("Got user: \(user)")
            self.session = User(
                uid: user.uid,
                displayName: user.displayName,
                email: user.email)
        } else {
            // if we don't have a user, set our session to nil
            self.session = nil
        }
    }
}

func signUp(
    email: String,
    password: String,
    handler: @escaping AuthDataResultCallback
    ) {
    Auth.auth().createUser(withEmail: email, password: password, completion: handler)
}

func signIn(
    email: String,
    password: String,
    handler: @escaping AuthDataResultCallback
    ) {
    Auth.auth().signIn(withEmail: email, password: password, completion: handler)
}

func signOut () -> Bool {
    do {
        try Auth.auth().signOut()
        self.session = nil
        return true
    } catch {
        return false
    }
}

func unbind () {
    if let handle = handle {
        Auth.auth().removeStateDidChangeListener(handle)
    }
}
}

用户.swift

import Foundation

class User {
var uid: String
var email: String?
var displayName: String?

init(uid: String, displayName: String?, email: String?) {
    self.uid = uid
    self.email = email
    self.displayName = displayName
}
}

Answer 1

您需要将属性包装器添加@Published到您var session的 SessionStore 中，以确保在更改时刷新所有使用它的视图。所以改变

var session: User? { didSet { self.didChange.send(self) }}

到

@Publishedvar session: User? { didSet { self.didChange.send(self) }}

有关更多信息，请参见此处：https : //www.hackingwithswift.com/quick-start/swiftui/how-to-use-environmentobject-to-share-data-between-views