Swift:尝试查询 api 时获取 nil

Question

我无法从 api 获取股票价格。我正在使用 SwiftyJSON 框架来接收数据。当我执行代码时，它在控制台中给我 nil 。我不知怎的找不到这个错误。

import UIKit

class ViewController: UIViewController
{
@IBOutlet weak var inputQuote: UITextField!

@IBAction func buttonTapped(sender: AnyObject)
{
    var stockQuote = inputQuote.text
    getJSON(stockQuote!)
}

override func viewDidLoad()
{
    super.viewDidLoad()
}

func getJSON(quote: String)
{

    let markitOnDemandURL = "http://dev.markitondemand.com/MODApis/Api/v2/Quote/jsonp?symbol=" + quote.uppercaseString + "&callback=myFunction"

    let url = NSURL(string: markitOnDemandURL)
    let request = NSURLRequest(URL: url!)
    let session = NSURLSession(configuration: NSURLSessionConfiguration.defaultSessionConfiguration())
    let task = session.dataTaskWithRequest(request) {(data, response, error) -> Void in

        if error == nil {

            let swiftyJSON = JSON(data: data!)
            let stockPrice = swiftyJSON["LastPrice"].stringValue
            print(stockPrice)
        }

        else
        {
            print("error")
        }
    }
    task.resume()
}

}

这是我正在使用的 API:http://dev.markitondemand.com/MODApis/Api/v2/Quote/jsonp?symbol=AAPL&callback=myFunction

如果您能查看我的代码并帮助我解决此问题，那就太好了。感谢您的努力。

Answer 1

当前您从该 api 获得的结果是

myFunction({"Status":"SUCCESS","Name":"Apple Inc","Symbol":"AAPL","LastPrice":116.05,"Change":1.98999999999999,"ChangePercent":1.74469577415395,"Timestamp":"Mon Oct 10 00:00:00 UTC-04:00 2016","MSDate":42653,"MarketCap":625328810150,"Volume":36235956,"ChangeYTD":105.26,"ChangePercentYTD":10.2508075242257,"High":116.75,"Low":114.72,"Open":115.02})

这是一个无效的 JSON

从开头删除 myFunction() 和末尾的 ) 将使其成为有效的 json

即

{
  "Status": "SUCCESS",
  "Name": "Apple Inc",
  "Symbol": "AAPL",
  "LastPrice": 116.05,
  "Change": 1.98999999999999,
  "ChangePercent": 1.74469577415395,
  "Timestamp": "Mon Oct 10 00:00:00 UTC-04:00 2016",
  "MSDate": 42653,
  "MarketCap": 625328810150,
  "Volume": 36235956,
  "ChangeYTD": 105.26,
  "ChangePercentYTD": 10.2508075242257,
  "High": 116.75,
  "Low": 114.72,
  "Open": 115.02
}

您可以使用各种工具，如 POSTMAN 或链接，如 http://jsonviewer.stack.hu/和 http://jsonlint.com/验证您的 JSON。