Question

我创建functionLibrary.swift类来调用某些不同的ViewControllers中的某些函数。问题是当我执行应用程序时，println中的ViewController.swift函数首先工作，尽管它是在我从functionLibrary调用的其他几行之后。

这是ViewController的logIn函数。（funcLib是functionLibrary类型的值）

 @IBAction func logIn(sender: AnyObject) {

        var bodyData = ["op":"users","op2":"login","id":"","id2":"","id3":"","users_emailAddress":"asdasd@gmail.com","users_password":"asdasd"]

        var requestData = funcLib.JSONStringify(bodyData) // This turns the data to string
        var responseData = funcLib.HTTPPostRequest(requestData) // This is the http post request. Returns a bool and a Dictionary

        println(responseData)

这是输出

(false, [:]) //responseData
response = <NSHTTPURLResponse: 0x7aad7290> { URL: http://asdasd.asdasd.com/services/index.php } { status code: 200, headers {
    Connection = "keep-alive";
    "Content-Length" = 57;
    "Content-Type" = "application/json";
    Date = "Sun, 26 Jul 2015 21:09:39 GMT";
    Server = asdasd;
    "X-Powered-By" = "PHP/5.4.43";
} }// The println in HTTPPostRequest
{
    auth = *********;
    "user_id" = ***;
} // The println in HTTPPostRequest

代码运行正常。没有运行时错误。但就像我说的那样首先执行println。如何在请求和响应之后执行它数据从funcLib函数获取数据？

谢谢。

Answer 1

看起来funcLib.HTTPPostRequest计划异步闭包并立即返回，而不等待HTTP响应。异步方法很好，但当然你不能期望在responseData中找到从HTTP服务器返回的任何数据，当然logIn中的println将立即执行，而HTTP的println响应将在以后发生，届时闭包将收到实际响应。

Answer 2

我使用dispach_async()方法解决了这个问题。

以下是新的HTTPPostRequest()功能：

func HTTPPostRequest(link:String, bodyData: AnyObject, completion:((data: NSData?) -> Void)) {


        println("HTTPPOST")

        if let requestURL = NSURL(string: link){

            let request = NSMutableURLRequest(URL: requestURL)
            request.HTTPMethod = "POST"
            let postString = JSONStringify(bodyData)
            request.HTTPBody = postString.dataUsingEncoding(NSUTF8StringEncoding)
            NSURLSession.sharedSession().dataTaskWithRequest(request){ (data, response, error) in
                completion(data: NSData(data: data))

                if let error = error {
                    println("error:\(error)")
                    return
                }

            }.resume()

       }

   }

以下是如何调用HTTPPostRequest()：

    @IBAction func logIn(sender: AnyObject) {

        var bodyData: AnyObject = ["op":"users","op2":"login","id":"","id2":"","id3":"","users_emailAddress":"asdasdasd","users_password":"asdasd"] as AnyObject

        let response: () = funcLib.HTTPPostRequest("http://asdasd.asdasdasd.com/services/index.php", bodyData: bodyData){data in

            dispatch_async(dispatch_get_main_queue()){


                if let data = data {
                    let responseData = NSData(data: data)
                    let responseDic = NSJSONSerialization.JSONObjectWithData(data , options: NSJSONReadingOptions.MutableContainers, error: nil) as! NSDictionary

                    println("\(responseDic)")

                }

            }

        }

    }

}

如何在我想要的时间执行代码的某些部分？

2 个答案: