Question

我正在尝试在prepareForSegue函数中使用post请求的响应。我想将响应值分配给目标viewController属性。我不能这样做，因为当我在侧边括号中分配它时，在查看新窗口之前不会分配。因为在封闭代码内部读取后，查看新窗口。

以及我尝试将saveInvoice函数赋值给变量并在NSUrlSessionDataTask函数中使用。但该变量为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) }类型，因此我无法进一步使用它。

下面我提到了我的代码段

调用函数

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
}

这是处理发布请求的功能

{{1}}

Answer 1

首先，saveInvoice是异步执行的，所以当下一个控制器加载但不久之后你就不会获得该值。

要保存变量，您需要在完成块内执行此操作。我想这是感兴趣的hash_key吗？

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，这是异步执行所以我宁愿认为最好开始保存，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

中

let savedHashKey:String? = nil

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

    previewVC.invoiceSummary = savedHashKey
    savedHashKey = nil
}

在另一个方法Swift中使用Post请求响应字符串

1 个答案: