xcode - 使用异步调用创建 Parse 服务以返回响应

Question

构建我的第一个 Swift 应用程序并使用 Parse 进行 Baas。 我将其包装在一个服务中，以便我可以检查数据输入并准备结果......让我的生活更轻松。但我不确定如何使用异步调用。

我通常让我的服务返回 success: Bool 的响应, message: String (错误原因)和 data: [AnyObject]为了结果。我来自 JS 世界，我习惯了回调，但不确定这里是如何工作的，因为 block 不返回数据......

class UserService {                    
    class func register(email: String, password: String) -> Response {    
        if email == "" || password == "" {
            return Response(success: false, message: "Please enter an email and password")
        }

        var user = PFUser()
        user.username = email
        user.email = email        

        user.signUpInBackgroundWithBlock { (succeeded: Bool, error: NSError?) -> Void in
             if let error = error {
                 let errorString = error.userInfo?["error"] as? NSString
                 // here I would like to return my response success: false, message: errorString
             } else {
                 // Hooray! Let them use the app now.
                 // Here I would like to return response success: true
             }
        }
        return Response(success: true, message: "")
    }

有关信息，以下是我在 ViewController 中调用服务的方式

@IBAction func registerBtn(sender: AnyObject) {
        registerBtnBtn.enabled = false
        let response: Response = UserService.register(emailInput.text, password: passwordInput.text)
        if !response.success {
            registerBtnBtn.enabled = true
            registerBtnBtn.setTitle("Registering", forState: .Normal)

            AlertTools.okAlert(self, title: "Something went wrong...", message: response.message)
        } else {
            self.performSegueWithIdentifier("registerToBabySegue", sender: self)
        }
    }

我的做法完全错误吗？ 非常感谢任何帮助。

Answer 1

使用 Apple 在其框架中使用的完成处理程序( block ):

typealias Response = (success: Bool, message: String?)

class UserService {
    class func register(email: String, password: String, completionHandler: ((Response)->())?) {
        if email == "" || password == "" {
            completionHandler?(Response(success: false, message: "Please enter an email and password"))
            return
        }

        let user = PFUser()
        user.username = email
        user.email = email

        user.signUpInBackgroundWithBlock { (succeeded: Bool, error: NSError?) -> Void in
            if let error = error {
                let errorString = error.userInfo?["error"] as? NSString
                completionHandler?(Response(success: false, message: errorString))
                // here I would like to return my response success: false, message: errorString
            } else {
                completionHandler?(Response(success: true, message: nil))
                // Hooray! Let them use the app now.
                // Here I would like to return response success: true
            }
        }
        completionHandler?(Response(success: true, message: nil))
    }

}

UserService.register("some@email.com", password: "12345") { (response: Response) -> () in
    // process response
}