Swift中转换为字符串的数字出错

我是Swift和Xcode的初学者,仍然不知道一些基本的东西。

当我从JSON解析数据时,总是遇到一些必须转换为字符串的数字。所有数字都变为零。为什么?

class SecondViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

var titlenews = ""
var title_segue = ""
var id_segue = ""

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "newsfeedCell", for: indexPath) as! NewsFeedCell
    cell.newsfeed_title.text = self.news?[indexPath.item].headline
    cell.newsfeed_topic.text = self.news?[indexPath.item].topic
    cell.newsfeed_time.text = timetime(from: (self.news?[indexPath.item].time)!)
    return cell
}

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    print("Launch tableview in SecondView")
    title_segue = (self.news?[indexPath.item].headline)!
    id_segue = (self.news?[indexPath.item].id)!
    print(("tableView: "+(self.news?[indexPath.item].headline)!))
    performSegue(withIdentifier: "newsbodysegue", sender: self)
}

func numberOfSections(in tableView: UITableView) -> Int {
    return 1
} 

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return self.news!.count
} //number of rows

@IBOutlet weak var tableview: UITableView!
var news: [Newsfeed]? = []

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

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

func getJSON(){

    let urlRequest = URLRequest(url: URL(string: "https://sportarena.com/wp-api/wp/v2/posts/?per_page=25")!)

    let task = URLSession.shared.dataTask(with: urlRequest) { (data,response,error) in

        if error != nil {
            print(error as Any)
            return
        }
        self.news = [Newsfeed]()
        do {
            let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as! NSArray

            for arrayX in json as! [[String: Any]] {
               let NF = Newsfeed()

                let categories0 = arrayX["categories"] as? NSArray
                let title0 = arrayX["title"] as? [String: Any]

                if let ID = arrayX["id"],
                    let date = arrayX["date"],
                    let status = arrayX["status"],
                    let title = title0!["rendered"],
                    let categories = categories0?[0] {
                        NF.headline = title as? String
                        NF.topic = status as? String
                        print (ID)
                        NF.id = ID as? String
                        NF.time = date as? String
                }
                self.news?.append(NF)
             }
            DispatchQueue.main.async {
                self.tableview.reloadData()
            }
        } catch let error {
            print(error)
        }
    }
    task.resume()
}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if (segue.identifier == "newsbodysegue") {
        let NewsBodyController = segue.destination as! NewsBody
        NewsBodyController.labeltext = id_segue
    }
}

}

行“id\u segue=(self.news?[indexPath.item].id)!”给定错误:在展开可选值时意外发现nil。

为什么nil if print(ID)显示从JSON解析的正确数字?