ios - 如何过滤 JSON 数据然后枚举过滤后的数据？

Question

我目前正在创建一个应用程序，它使用仅持续特定时间的“定时奖励”，我不熟悉在 Swift 中使用过滤器，我需要满足的当前目标:

1. 如果 redemptionDate 为 NULL，则显示奖励

2. 如果 currentDateTime >= redemptiondate + redeemTimeLimit(这些是 JSON 对象)则隐藏奖励

3. 如果 currentDateTime < redemptiondate + redeemTimeLimit 则显示奖励和倒数计时器

4. 倒计时计时器的数量是 redemptiondate + redeemTimeLimit 和 currentDateTime 之间的差值

到目前为止，这是我的代码，我遇到过几次崩溃，注释在代码中。我还对我尝试满足上述标准的区域进行了编号:

   var rewardsArray : [MemberRewardsInfo] = []//MemberRewarsInfo is a JSON Object custom class
  var timeFilteredRewardsArray : [MemberRewardsInfo] = []

 RewardManager.sharedInstance.updateRewards({ rewards in

self.timeFilteredRewardsArray = rewards


  //.1
  self.timeFilteredRewardsArray = self.timeFilteredRewardsArray.filter ({$0.redemptionDate == nil})


for filteredReward in self.timeFilteredRewardsArray {


  let Date = NSDate()
  let df = NSDateFormatter()
  df.timeZone = NSTimeZone(forSecondsFromGMT: 0)
  df.dateFormat = "MM-dd-yyyy"
  let currentDate = df.stringFromDate(Date)

  //.2
  if currentDate >= filteredReward.redemptionDate! + filteredReward.redeemTimeLimit! {

            //remove current reward from array, not sure how to do this

    //.3
  } else if currentDate < filteredReward.redemptionDate! + filteredReward.redeemTimeLimit!{

    //.4
    var countdownTimer = (filteredReward.redemptionDate! + filteredReward.redeemTimeLimit!) - currentDate

       //error occurs here: "Binary operator '-' cannot be applied to two 'String' operands"
  }
}



   self.rewardsArray =  self.timeFilteredRewardsArray
    self.rewardsTableView.reloadData()

  })

Answer 1

我推荐你使用这个库 SwiftyJSON . Swift 对类型非常严格，而 JSON 不关心类型。链接也变得一团糟，SwiftyJSON 修复了所有这些。它将帮助您专注于过滤器，因为您正在过滤数组然后将其分配给同一个数组...

快速示例，因为我不知道您的 json 结构:

let json = JSON(data: dataFromNetworking)
if let userName = json[0]["data"]["date"].string {
  //convert to date and do your filters
}