SwiftUI视图未更新为EnvironmentObject更改

我正在创建一个包含Firebase的SwiftUI应用程序，该应用程序允许登录到一个非常简单的帐户，只需一个带有密码和电子邮件字段的ui表单，然后单击一个提交按钮即可。用户登录后，我将firebase用户对象存储在EnvironmentObject中，以便其余视图可以访问它。该应用程序当前存在的问题是，一旦用户登录并将用户数据存储在EnvironmentObject中，则该视图应更新为此状态的更改状态以显示不同的屏幕，但似乎该视图仍认为EnvironmentObject等于零。视图是否不会像状态变量那样自动更改为EnvironmentObject中的更新？

我确保正确设置了EnvironmentObject并将其传递给预览和SceneDelegate

通过在登录时将帐户信息打印到控制台来确保应用程序确实成功登录了用户，但是视图本身仅显示nil表示帐户信息，看来它不会使用用户信息访问更新的EnvironmentObject。

import SwiftUI
import Firebase
import Combine

struct ContentView: View {

    @EnvironmentObject var session: SessionStore

    @State var emailTextField: String = ""
    @State var passwordTextField: String = ""

    @State var loading = false
    @State var error = false

    var body: some View {
        VStack {
            if (session.session != nil) {
                Home()
            } else {
                Form {
                    TextField("Email", text: $emailTextField)
                    SecureField("Password", text: $passwordTextField)
                    Button(action: signIn) {
                        Text("Sign in")
                    }
                }

                Text("Session: \(session.session?.email ?? "no user")")
            }
        }.onAppear(perform: getUser)
    }

    func getUser () {
        session.listen()
    }

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

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView().environmentObject(SessionStore())
    }
}



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 account = user {
                // if we have a user, create a new user model
                print("Got user: \(account)")
                self.session = User(
                    uid: account.uid,
                    displayName: account.displayName,
                    email: account.email
                )
                print("Session: \(self.session?.email ?? "no user")")
            } 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)
        }
    }
}

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
    }

}

正如您在视图中看到的那样，应该在用户未登录时呈现登录字段，并且当用户登录时，该视图应显示另一个视图。该其他视图未显示。