我正在创建一个 SwiftUI 应用程序,其中包含 Firebase 来启用帐户登录,非常简单,只是一个带有密码和电子邮件字段的 ui 表单,然后是一个提交按钮。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。目前应用程序的问题是,一旦用户登录并且用户数据存储在EnvironmentObject中,视图应该更新到更改后的状态以显示不同的屏幕,但似乎视图仍然认为EnvironmentObject等于零。视图是否不会像状态变量那样自动更改为环境对象中的更新?
我已确保环境对象设置正确并传递给预览和 SceneDelegate
确保应用程序确实通过在登录时将帐户信息打印到控制台来成功登录用户,但视图本身仅显示帐户信息为零,似乎它不会使用用户信息访问更新的环境对象。
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,当用户未登录时,它应该呈现登录字段,而当用户登录时,视图应该显示另一个视图。其他视图未显示。