ios - swift 中的日期格式错误

Question

我是 swift 库的新手。我正在快速使用日历，我想在日历中显示事件。这些事件是从 Json API 获得的，但是当我比较日期时它显示错误。

这是代码

  let data = event["date"] as? String
  let newString = data?.replacingOccurrences(of: "/", with: "-")
  self.FirstData = self.EventDates[0]

比较函数

 func compareDate(date : String){
        let date = date

        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss"
      ====>>>>Error in line 
  let dateFromString : NSDate = dateFormatter.date(from: date)! as NSDate 
        dateFormatter.dateFormat = "yyyy-MM-dd"
        let datenew = dateFormatter.string(from: dateFromString as Date)
        print("datee",datenew)

    }

错误: fatal error :在展开可选值时意外发现 nil

如何比较日期或解决此问题。

Answer 1

试试这个:-

func convertDate(date:String) -> String {
     let dateFormatter = DateFormatter()
    let tempLocale = dateFormatter.locale // save locale temporarily
    dateFormatter.locale = Locale(identifier: "en_US_POSIX") 
   // date format getting from server 
     dateFormatter.dateFormat = "YYYY-MM-dd'T'HH:mm:ss.SSSSSS'Z'"

    let date = dateFormatter.date(from: date)!
    //date format you want
    dateFormatter.dateFormat = "yyyy-MM-dd"
    dateFormatter.locale = tempLocale // reset the locale
    let dateString = dateFormatter.string(from: date)
    print("EXACT_DATE : \(dateString)")
    return dateString
 }