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?
我已确保正确设置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该应用程序确实能够成功登录用户,但是视图本身仅显示nil作为帐户信息,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,而当用户登录时,该视图应显示另一个视图。该其他视图未显示。
答案 0 :(得分:3)
尝试使用@Published属性。 尝试实现以下内容:
class SessionStore : ObservableObject {
@Published var session: User
}
class User: ObservableObject {
@Published var uid: String
@Published var email: String?
@Published var displayName: String?
init(uid: String, displayName: String?, email: String?) {
self.uid = uid
self.email = email
self.displayName = displayName
}
}
当用户对象(例如电子邮件或显示名称)发生更改时,这应该会更新您的视图,因为它们已发布。 希望这会有所帮助,gl
已更新:
由于SwiftUI还不支持嵌套的Observable,因此您需要自己通知主模型。
请参见以下代码片段,如何在ObservableObject中使用嵌套的ObservableObject:
class Submodel1: ObservableObject {
@Published var count = 0
}
class Submodel2: ObservableObject {
@Published var count = 0
}
class Model: ObservableObject {
@Published var submodel1: Submodel1 = Submodel1()
@Published var submodel2: Submodel2 = Submodel2()
var anyCancellable: AnyCancellable? = nil
var anyCancellable2: AnyCancellable? = nil
init() {
anyCancellable = submodel1.objectWillChange.sink { (_) in
self.objectWillChange.send()
}
anyCancellable2 = submodel2.objectWillChange.sink { (_) in
self.objectWillChange.send()
}
}
}
当子模型中的数据更改时,主模型将通知自己。这将导致视图上的更新。
让我知道这是否对您有帮助。.祝你好运!
答案 1 :(得分:-1)
您认为您将ObservableObject
与BindableObject
混为一谈了吗?可以尝试以下方法:
@Published var session: User?