使用 swift 从解析的 Json 中提取数据

Question

我想从我之前解析过的 JsonObject 中获取我的 CampaignList。但是它在运行时会出现致命错误。

错误

“致命错误：在展开可选值时意外发现 nil”

self.CampaignArray = Campaigns as! NSMutableArray  

代码：

var CampaignArray:NSMutableArray = []

func Get(){
    let res: String = ""

    let jsonObject = ["PhoneNumber": "xxxxx"]
    let Jsn = JsonClass(value: jsonObject, text: res)

    Alamofire.request(.POST, "http://MYURL",parameters: jsonObject,
        encoding: .JSON).validate(statusCode: 200..<303)
        .validate(contentType: ["application/json"])
        .responseJSON { (response) in
            NSLog("response = \(response)")

            switch response.result {
            case .Success:
                guard let resultValue = response.result.value else {
                    NSLog("Result value in response is nil")
                    //completionHandler(response: nil)
                    return
                }
                let responseJSON = resultValue
                print(responseJSON)
                let result = Jsn.convertStringToDictionary(responseJSON as! String)!
                print("result: \(result)")
                let Campaigns = (result as NSDictionary)["Campaigns"]
                print(Campaigns)
                self.CampaignArray = Campaigns as! NSMutableArray
                let notifications = (result as NSDictionary)["Notifications"]
                print(notifications)
                break
            case .Failure(let error):
                NSLog("Error result: \(error)")
                // Here I call a completionHandler I wrote for the failure case
                return
            }
    }
}

而我的回应 Json 是：

json: {"CampaignList":[
         {"Bonus":"5","CampaignId":"zQUuB2RImUZlcFwt3MjLIA==","City":"34"} 
          {"Bonus":"3","CampaignId":"VgYWLR6eL2mMemFCPkyocA==","City":"34"}],
 "MemberId":"ZBqVhLv\/c2BtMInW52qNLg==",     
 "NotificationList":[{"Notification":"Filiz Makarnadan Milli Piyango Çekiliş Hakkı Kazanmak İster misin ?","PhoneNumber":"555555555"}]}

Answer 1

您提供的 JSON 无效。 Campaigns 字典中缺少,。 有效的 JSON 如下所示：

{
  "CampaignList": [
    {
      "Bonus": "5",
      "CampaignId": "zQUuB2RImUZlcFwt3MjLIA==",
      "City": "34"
    },
    {
      "Bonus": "3",
      "CampaignId": "VgYWLR6eL2mMemFCPkyocA==",
      "City": "34"
    }
  ],
  "MemberId": "ZBqVhLv/c2BtMInW52qNLg==",
  "NotificationList": [
    {
      "Notification": "Filiz Makarnadan Milli Piyango Çekiliş Hakkı Kazanmak İster misin ?",
      "PhoneNumber": "555555555"
    }
  ]
}

致命错误：在展开可选值时意外发现 nil

您收到此错误是因为您尝试将 nil 转换为 NSDictionary 对象。 您提供的 JSON 中没有 Campaigns 密钥，因此当您尝试从 JSON 获取此密钥时，您将得到 nil。在下一步中，您尝试将此 nil 转换为 NSDictionary。

尝试使用CampaignList 键来获取您想要的数据。

let result: [String: AnyObject] = Jsn.convertStringToDictionary(responseJSON as! String)!
let campaigns: [Campaign] = result["CampaignList"] as! [Campaign]
print(Campaigns)
self.CampaignArray = campaigns 
let notifications = result["NotificationList"]
print(notifications)

JSON 字典中的 Notifications 键也是如此。

你还应该在objective-c NSDictionary 和NSArray 上使用swift 类型。

Answer 2

尝试使用 SwiftyJSON (https://github.com/SwiftyJSON/SwiftyJSON)

这个库（pod）非常简单，有详细的文档。

你的例子：

我将子文件“data.json”放在我的项目中并阅读它。感谢 Daniel Sumara 对您的 json 示例进行更正。

  if let path = NSBundle.mainBundle().pathForResource("data", ofType: "json") {
        if let data = NSData(contentsOfFile: path) {
            let json = JSON(data: data)

            if let CampaignList = json["CampaignList"].array {
                for index in 0 ..< CampaignList.count {

                    print("Campaign [\(index)]")
                    if let CampaignId = CampaignList[index]["CampaignId"].string {
                        print("     CampaignId: \(CampaignId)")
                    }

                    if let City = CampaignList[index]["City"].string {
                        print("     City: \(City)")
                    }

                    if let Bonus = CampaignList[index]["Bonus"].string {
                        print("     Bonus: \(Bonus)")
                    }
                }
            }

            if let MemberId = json["MemberId"].string {
                print("MemberId: \(MemberId)")
            }

            if let NotificationList = json["NotificationList"].array {
                print("NotificationList")
                for notification in NotificationList {
                    if let Notification = notification["Notification"].string {
                         print("     Notification: \(Notification)")
                    }

                    if let PhoneNumber = notification["PhoneNumber"].string {
                        print("     PhoneNumber: \(PhoneNumber)")
                    }
                }
            }
        }
    }

你也可以使用 Alamofire-SwiftyJSON (https://github.com/SwiftyJSON/Alamofire-SwiftyJSON)

附：您有致命错误，因为您不检查 value 是否为 nil。阅读“if let”表达式 (https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/OptionalChaining.html)