Swift dataTaskWithRequest完成块未执行

Question

我有一个函数,它将字典发回服务器,并在出现错误时返回状态代码或错误内容.它有时工作正常,而其余的时间则跳过完成部分.

func postData(url: String, query: NSDictionary) ->NSObject? {
   var error: NSError?
   var result: NSObject? = nil

   let dest = NSURL("http://myUrl.com")
   let request = NSMutableURLRequest(URL: dest!)
   request.HTTPMethod = "POST"
   request.HTTPBody = NSJSONSerialization.dataWithJSONObject(query, options: NSJSONWritingOptions.allZeros, error: &err)
   request.addValue("application/json", forHTTPHeaderField: "Content-Type")
   request.addValue("application/json", forHTTPHeaderField: "Accept")

   let task = NSURLSession.sharedSession().dataTaskWithRequest(request){
              data, response, error in
              if(error != nil){
                   println(error)
                   result = error 
                   return
              }
              result = (response as! NSHTTPURLResponse).statusCode
              return
    }
    task.resume()
    return result
}

我提到NSURLSession dataTaskWithRequest没有被调用,并且知道它可能是由执行时间延迟引起的.但是,由于我需要状态代码(到目前为止返回nil)来确定帖子后要执行的操作,我想知道如何解决这个问题？

Answer 1

你的方法是异步方法,你无法从中获得回报.

您可以通过返回来传递一个块来处理您的操作

func postData(url: String, query: NSDictionary,finished:(NSObject)->()) {
var error: NSError?
var result: NSObject? = nil

let dest = NSURL("http://myUrl.com")
let request = NSMutableURLRequest(URL: dest!)
request.HTTPMethod = "POST"
request.HTTPBody = NSJSONSerialization.dataWithJSONObject(query, options: NSJSONWritingOptions.allZeros, error: &err)
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("application/json", forHTTPHeaderField: "Accept")

let task = NSURLSession.sharedSession().dataTaskWithRequest(request){
    data, response, error in
    if(error != nil){
        println(error)
        result = error
        return
    }
    finished((response as! NSHTTPURLResponse).statusCode)
}
task.resume()
}

然后使用它

postData(url, dic) { (object:NSObject) -> () in{
//use here
}