ios - 在另一种方法 Swift 中使用 Post 请求响应字符串

Question

我正在尝试在 prepareForSegue 函数中使用发布请求的响应。我想将响应值分配给目标 viewController 属性。我不能那样做，因为当我在侧闭括号中分配它时，在查看新窗口之前不会分配。因为在关闭代码中读取，在查看新窗口之后。

以及我尝试将 saveInvoice 函数分配给一个变量并在 prepareForSegue 函数中使用。但该变量是 NSUrlSessionDataTask 类型，所以我无法进一步使用它。

下面我提到了我的代码段

调用函数

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    let previewVC :PreviewViewController = segue.destinationViewController as! PreviewViewController

    previewVC.invoiceSummary = "test hash key"

    let invoiceSave = saveInvoice({ hash_key in
        print(hash_key)
        let test = hash_key
        if test != ""
        {
            print("Success")
        }
        previewVC.sendersName = "sender view controller name"
        })

    print(invoiceSave)
}

这是处理post请求的函数

func saveInvoice(completionHandler: (NSString) -> Void) -> NSURLSessionDataTask
{
    let invoiceSummary = "Sample invoice summary"
    let invoiceDate = "2015-11-20"
    let invoiceConnectionID = "647193"

    //let json = ["summary": invoiceSummary, "date": invoiceDate, "business_id": invoiceConnectionID]
    let json = NSMutableDictionary()

    json.setValue(invoiceSummary, forKey: "summary")
    json.setValue(invoiceDate, forKey: "2015-11-20")
    json.setValue(invoiceConnectionID, forKey: "business_id")

    let data = try? NSJSONSerialization.dataWithJSONObject(json, options: NSJSONWritingOptions(rawValue: 0));

    let request = NSMutableURLRequest(URL: NSURL(string: "https://livetest.somedomain.com/api/invs?auth_token=jmkm6ijijejf23kmkdd")!)

    request.HTTPMethod = "POST"
    request.addValue("application/json",forHTTPHeaderField: "Content-Type")
    request.addValue("application/json",forHTTPHeaderField: "Accept")
    request.HTTPBody = data

    var outer = ""
    let task = NSURLSession.sharedSession().dataTaskWithRequest(request){
        data, response, error in

        let responceJSon = JSON(data: data!)

        //let text = self.passJson(responceJSon)

        let invoice = responceJSon["invoice"]

        let hash_key = invoice["hash_key"].stringValue
        let statement_number = invoice["statement_no"].stringValue
        let statement_summary = invoice["summary"].stringValue
        let statement_date = invoice["date"].stringValue

        let obj = ["hash_key": hash_key, "statement_no": statement_number, "summary": statement_summary, "date": statement_date]
        self.invObject.append(obj)


        //self.invObject.append(text as! [String : String])
        outer = self.invObject[0]["statement_no"]!
        print(outer)

        if let hash_key = invoice["hash_key"].string{

            completionHandler(hash_key)
            return
        }


    }
    task.resume()
    return task
}

Answer 1

首先，saveInvoice 是异步执行的，因此在下一个 Controller 加载时您不会获得值，但会在稍后加载。

要保存变量，您需要在完成 block 中执行此操作。我猜这里感兴趣的是 hash_key？

所以你会做这样的事情

saveInvoice({ hash_key in
    previewVC.hash_key = hash_key
    previewVC.sendersName = "sender view controller name"
})

但是，如上所述，这是异步执行的，所以我认为最好是开始保存，然后在从 saveInvoice 中调用完成处理程序时以编程方式执行 segue

saveInvoice({ hash_key in
    savedHashKey = hash_key
    self.performSegueWithIdentifier(segueName, sender: self)
})

然后在 prepareForSegue

let savedHashKey:String? = nil

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    let previewVC :PreviewViewController = segue.destinationViewController as! PreviewViewController

    previewVC.invoiceSummary = savedHashKey
    savedHashKey = nil
}