Alamofire request coming up nil

Question

I'm developing an iOS app which user WebServices and I find Alamofire just perfect for what I'm doing but I'm having a problem; the app asks the user to login which is an Alamofire call and does it just fine.

The problem is, it has to create a collection view based on the content of another Alamofire request but is always printf("\n$%0.2f", amount[i]); .

nil

The same codeblock works perfect for the Login but doesn't in this case BTW the debug Print always print func getJSON(URLToRequest: String) -> JSON { let comp:String = (prefs.valueForKey("COMPANY") as? String)! let params = ["company":comp] var json:JSON! let request = Alamofire.request(.POST, URLToRequest, parameters: params).responseJSON { response in switch response.result { case .Success: if let value = response.result.value { json = JSON(value) } default: json = JSON(""); } } debugPrint(request.response) return json; }

Answer 1

您在设置之前尝试访问request.response，请记住Alamofire 异步，因此您必须使用闭包返回JSON，但是请记住，Alamofire也会返回错误，因此我强烈建议您使用以下代码：

func getJSON(URLToRequest: String, completionHandler: (inner: () throws -> JSON?) -> ()) {

   let comp:String = (prefs.valueForKey("COMPANY") as? String)!
   let params = ["company":comp]

   let request = Alamofire.request(.POST, URLToRequest, parameters: params).responseJSON {
    response in

    // JSON to return
    var json : JSON?

    switch response.result {
    case .Success:

        if let value = response.result.value {
            json = JSON(value)
        }

        completionHandler(inner: { return json })

    case .Failure(let error):
        completionHandler(inner: { throw error })
    }
} 

诀窍是getJSON函数采用类型为'inner'的名为() throws -> JSON?的附加闭包。这个闭包将提供计算结果，或者它将抛出。闭包本身是在计算过程中通过以下两种方法之一构建的：

• 如果出现错误：inner: {throw error}
• 如果成功：inner: {return json}

然后你就可以这样称呼它：

self.getJSON("urlTORequest") { (inner: () throws -> JSON?) -> Void in
  do {
     let result = try inner()
  } catch let error {
     print(error)
  }
}

我希望这对你有所帮助。