swift - Alamofire URL 请求 - 解包可选值时意外发现 nil

Question

所以我有一个 PageViewController 来管理包含一系列股票代码、价格等的各种 VC。

我使用 Alamofire 来管理模型中的 API 调用。以下是模型及其问题的简短摘要:

struct Stock {
    var last: String?
    var companyName: String?
    var symbol: String?

    var dataFields: [[String : String]]
}

class SwiftStock {
  class func fetchStockForListOfSymbols(#symbols: Array<String>, completion:(stock: Stock) -> ()) {

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)) {

      var stockURL = "http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20yahoo.finance.quotes%20where%20symbol%20in%20(%22\(symbols)%22)&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys&format=json"

      request(.GET, stockURL)
        .responseJSON { (_, response, resultsJSON, _) in

          if response?.statusCode == 200 {

            if let stockData = (((resultsJSON as! [String : AnyObject])["query"] as! [String : AnyObject])["results"] as! [String : AnyObject])["quote"] as? [String : AnyObject] {

              // lengthy creation, yeah
              var dataFields = [[String : String]]()

              dataFields.append(["Last" : stockData["LastTradePriceOnly"] as? String ?? "N/A"])
              dataFields.append(["Company" : stockData["Name"] as? String ?? "N/A"])
              dataFields.append(["Symbol" : stockData["Symbol"] as? String ?? "N/A"])

              let stock = Stock(
                last: dataFields[0].values.array[0],
                companyName: dataFields[1].values.array[0],
                symbol: dataFields[2].values.array[0],
                dataFields: dataFields
              )
              dispatch_async(dispatch_get_main_queue()) {
                completion(stock: stock)
              }
            }
          }
      }
    }
  }

在 Alamofire 的 URLRequest 期间解包可选值时意外发现 nil。不知道我哪里搞砸了。有什么建议吗？

PageViewController上的代码如下:

class PageViewController: UIPageViewController, UIPageViewControllerDataSource
{
  var symbols: Array<String> = ["CMG", "TSLA", "FB", "SHAK"]
  var prices = [""]

  var stock: Stock?

  override func viewDidLoad() {
    super.viewDidLoad()

    // Set the data source to itself
    dataSource = self

    // Create the first screen
    if let startingViewController = self.viewControllerAtIndex(0) {
      setViewControllers([startingViewController], direction: .Forward, animated: true, completion: nil)
    }
  }

  override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)
    updateUI()
  }

  func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {

    var index = (viewController as! MainViewController).index
    index++
    return self.viewControllerAtIndex(index)
  }

  func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {

    var index = (viewController as! MainViewController).index
    index--
    return self.viewControllerAtIndex(index)
  }

  func viewControllerAtIndex(index: Int) -> MainViewController? {
    if index == NSNotFound || index < 0 || index >= self.symbols.count {
      return nil
    }

    // Create a new view controller and pass suitable data.
    if let pageContentViewController = storyboard?.instantiateViewControllerWithIdentifier("PageContentViewController") as? MainViewController {
      pageContentViewController.symbol = symbols[index]
      pageContentViewController.price = prices[index]
      pageContentViewController.index = index
      pageContentViewController.pageCount = symbols.count

      return pageContentViewController
    }
    return nil
  }

  func updateUI() {

    SwiftStock.fetchStockForListOfSymbols(symbols: symbols) { (stock) -> () in

      self.prices = ["\(stock.last!)"]
    }
  } 

}

Answer 1

您的网址错误，如果您将网址复制并粘贴到浏览器中，它应该返回 json，但实际上返回的是这个

{
  error: {
  lang: "en-US",
description: "Query syntax error(s) [line 1:54 mismatched character  '(' expecting set null,line 1:65 mismatched character ' ' expecting '"']"
}
}

这是不使用库来检索股票代码的完整代码:

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        let url = NSURL(string: "http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20yahoo.finance.quotes%20where%20symbol%20in%20(%22CMG%22%2C%20%22TSLA%22%2C%20%22FB%22%2C%20%22SHAK%22)&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys&format=json")
        let session = NSURLSession.sharedSession()



        let dataTask = session.dataTaskWithURL(url!) { (data, response, error) -> Void in
            if(error != nil){
                print("Something wrong")
            }

            do{
                let jsonData:NSDictionary = try NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions.AllowFragments) as! NSDictionary
                if let quote = jsonData["query"]?["results"] as? NSDictionary {
                    if let quoteArray = quote["quote"] as? NSArray {
                        for quoteItem in quoteArray {
                            print(quoteItem["symbol"] as! NSString)
                        }
                    }
                }

            } catch{

            }


        }

        dataTask?.resume()
    }




}