ios - 想要在 firebase 身份验证完成后调用方法

Question

   func signUpPressed(){
    guard let email = signupview.emailTextField.textField.text, let password = signupview.passwordTextField1.textField.text, let name = signupview.nameTextField.textField.text else{
        return
    }
    Auth.auth().createUser(withEmail: email, password: password, completion: {(User, error) in

        if error != nil{
            print(error)
            return
        }
        let ref  = Database.database().reference()
        let uid = User?.user.uid!
        let userReference = ref.child("Users").child((uid)!)
        let values = ["name": name, "email": email]
        userReference.updateChildValues(values, withCompletionBlock: {(err, ref) in

            if err != nil{
                print(err)
                return
            }
            print("User saved to firebase")
        })
    })
    getUserInfo()     
}

我希望由此实现的是能够在 firebase 创建用户后存储所有用户信息。问题是 getUserInfo 方法在 print("User saving to firebase") 之前执行。我还了解到 Firebase 是异步的，这意味着调用总是立即返回，而不会阻塞代码等待结果。稍后，只要准备好，结果就会出来。现在我想要做的是在结果“进来”之后调用一个方法。我怎样才能做到这一点？

Answer 1

异步不会阻塞主线程，也不会阻止方法

getUserInfo()   

在响应返回之前运行，因此您需要将其插入到 updateChildValues 的完成 block 中，如下所示

func signUpPressed(){
    guard let email = signupview.emailTextField.textField.text, let password = signupview.passwordTextField1.textField.text, let name = signupview.nameTextField.textField.text else{
        return
    }
    Auth.auth().createUser(withEmail: email, password: password, completion: {(User, error) in

        if error != nil{
            print(error)
            return
        }
        let ref  = Database.database().reference()
        let uid = User?.user.uid!
        let userReference = ref.child("Users").child((uid)!)
        let values = ["name": name, "email": email]
        userReference.updateChildValues(values, withCompletionBlock: {(err, ref) in

            if err != nil{
                print(err)
                return
            }

             getUserInfo()   

            print("User saved to firebase")
        })
    })

}