ios - firebase 身份验证 ios 使用未解析的标识符 'handle'

Question

我正在尝试关注这个 tutorial用于 Firebase 身份验证。我只是遵循了代码，但仍然出现 使用未解析的标识符“句柄” 错误。

代码:

import UIKit
import Firebase
import FirebaseAuth

class SignInViewController: UIViewController {

    override func viewWillAppear(_ animated: Bool) {
        handle = Auth.auth().addStateDidChangeListener { (auth, user) in   // ERROR HERE
            // ...
        }
    }

    override func viewWillDisappear(_ animated: Bool) {
        Auth.auth().removeStateDidChangeListener(handle!)    // ERROR HERE
    }
}

知道我应该做什么吗？谢谢!

    @IBAction func createAccount(_ sender: Any) {


        let emailTextD = self.emailText.text!
        let passwordTextD = self.passwordText.text

        Auth.auth().createUser(withEmail: emailTextD, password: passwordTextD!) { (authResult, error) in
            // ...
        }
    }

Answer 1

像这样将变量声明添加到类中:

  var handle: AuthStateDidChangeListenerHandle?