ios - Firebase - 闭包内的用户和 currentUser nil

Question

我在尝试获取 uid 时遇到了 Firebase 问题变量为 Auth.auth().currentUser?.uid似乎返回零。

我在函数周围放置了各种打印语句(我在下面发布了完整的函数)以查看它们是否被调用 - 如果我在 if let user = user 中放置打印语句，它不会被调用。如果我注释掉if let user = user (及其右括号)，打印语句被成功调用，所以我猜 user为零。

现在，如果我将打印放在 guard let uid = Auth.auth().currentUser?.uid else {return} 之后， print 语句再次没有被调用，让我相信 uid为零并且守卫语句正在返回。

我不知道为什么user和Auth.auth().currentUser?.uid这里都为零。我如何更改此设置以成功获取我的 uid变量？

这是提供一些上下文的完整函数:

@IBAction func emailSignupNextPressed(_ sender: Any) {
    // Make sure text fields aren't empty
    guard nameField.text != "", emailField.text != "", passwordField.text != "", confirmPasswordField.text != "" else {return}

    if passwordField.text == confirmPasswordField.text {
        Auth.auth().createUser(withEmail: emailField.text!, password: passwordField.text!, completion: { (user, error) in

            if let error = error {
                print(error.localizedDescription)
            }

            if let user = user {

                guard let uid = Auth.auth().currentUser?.uid else {return}

                // Use name as Firebase display name for readability
                let changeRequest = Auth.auth().currentUser!.createProfileChangeRequest()
                changeRequest.displayName = self.nameField.text!
                changeRequest.commitChanges(completion: nil)

                // Create child node from userStorage "users". Profile image set to user's unique ID
                let imageRef = self.userStorage.child("\(uid).jpg")
                let data = UIImageJPEGRepresentation(self.selectProfileImageView.image!, 0.5)

                // Upload image to Firebase
                let uploadTask = imageRef.putData(data!, metadata: nil, completion: { (metadata, err) in
                    if err != nil {
                                                    print(err!.localizedDescription)
                    }
                    imageRef.downloadURL(completion: { (url, er) in
                        if er != nil {
                                                            print(er?.localizedDescription as Any)
                        }
                        if let url = url {


                            emailUserPicString = url.absoluteString
                            print("\n\n\npic:\(emailUserPicString)\n\n\n")

                            if emailUserPicString == "" {

                                let alertController = UIAlertController(title: "Profile Picture Error", message: "Don't forget to choose a profile picture!", preferredStyle: UIAlertControllerStyle.alert)

                                let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: {(alert :UIAlertAction!) in
                                })
                                alertController.addAction(okAction)

                                self.present(alertController, animated: true, completion: nil)

                                return

                            } else {
                                self.performSegue(withIdentifier: "emailToSetup", sender: nil)
                            }





                        }
                    })
                })
                uploadTask.resume()
            }
        })
    } else {
        print("Passwords don't match")
        passwordAlert()
    }
}

Answer 1

auth().currentUser 仅当用户登录时才会返回 user。

您刚刚创建了该用户，因此尚未登录。

您通常可以从传递到 block 中的user获取uid，例如:

let uid = user.uid

如果 user 为空，则帐户创建失败，您应该检查错误。我注意到你正在使用

print(error.localizedDescription)

但您可能想使用:

print(error)

如果错误没有本地化描述。

通常，错误要么意味着网络问题，要么用户已经拥有帐户。

<小时/>

顺便说一句，如果您想让用户登录，您可以使用

Auth.auth().signIn(withEmail: email, password: password) { … }