使用 Alamofire 快速关闭 [英] Swift closure with Alamofire

问题描述

我正在对服务器进行 API 调用.我正在利用 Alamofire 来处理这个问题.我正在尝试创建一个函数，该函数使用 Alamofire 的 GET 函数返回一个基于自定义类的对象，该类包含此 GET 函数提供的各种输出.

I am making API calls to a server. I am leveraging Alamofire to handle this. I'm trying to create a function that uses Alamofire's GET function to return an object based on a custom class that holds the various outputs provided by this GET function.

我不清楚这样做的方式.

It's not clear to me the way in which to do this.

这是我的自定义类，用于保存有关响应的详细信息:

Here's my custom class that will hold details about the response:

import Foundation

class ResponsePackage {

    var success = false
    var response: AnyObject? = nil
    var error: NSError? = nil

}

在另一个类中，我有以下功能:

In another class I have the following function:

func get(apiEndPoint: NSString) -> ResponsePackage {

    let responsePackage = ResponsePackage()

        Alamofire
            .request(.GET, apiEndPoint)
            .responseJSON {(request, response, JSON, error) in
                responsePackage.response = JSON
                responsePackage.success = true
                responsePackage.error = error
        }

    return responsePackage

}

这将返回 nil，因为在 return 执行之前对服务器的调用尚未完成.我知道我应该能够用闭包来做到这一点，但我不知道如何构造它.

This returns nil as the call to the server is not complete before the return gets executed. I know that I should be able to do this with closures, but I am not sure how to construct this.

推荐答案

{} 之间的代码相当于 Objective-C 中的代码块:这是一段异步执行的代码.

The code between the {} is the equivalent of block in objective-C : this is a chunk of code that gets executed asynchronously.

您犯的错误是您放置 return 语句的位置:当您启动请求时，{} 中的代码在框架收到响应之前不会执行，因此当 return 语句到达，很可能，仍然没有响应.您可以简单地移动该行:

The error you made is where you put your return statement : when you launch your request, the code in {} is not executed until the framework received a response, so when the return statement is reached, chances are, there is still no response. You could simply move the line :

return responsePackage

在闭包内，所以 func 只有在收到响应时才返回.这是一种简单的方法，但它并不是真正的最佳方法:您的代码将卡在等待答案中.最好的方法是使用闭包.这看起来像:

inside the closure, so the func return only when it has received a response. This is a simple way, but it's not really optimal : your code will get stuck at waiting for the answers. The best way you can do this is by using closure, too. This would look something like :

   func get(apiEndPoint: NSString, completion: (response: ResponsePackage) -> ()) -> Bool {

        let responsePackage = ResponsePackage()
        Alamofire
            .request(.GET, apiEndPoint)
            .responseJSON {(request, response, JSON, error) in
                responsePackage.response = JSON
                responsePackage.success = true
                responsePackage.error = error

                completion(response: responsePackage)
        }
    }

这篇关于使用 Alamofire 快速关闭的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！