swift - 如何在Swift中以短格式获取当前日期

在下面的图像中，您可以看到我编写的代码以及所有变量的值:

class fun getCurrentShortDate() -> String {
    var todaysDate = NSDate()
    var dateFormatter = NSDateFormatter()
    dateFormatter.dateFormat = "dd-MM-yyyy"
    var DateInFormat = dateFormatter.stringFromDate(todaysDate)

    return DateInFormat
}

Variable values

如您所见，发现当前日期没有问题，但是当我尝试将NSDate更改为字符串时，它将无法执行。

最佳答案

Xcode 11或更高版本•Swift 5.1或更高版本

extension TimeZone {
    static let gmt = TimeZone(secondsFromGMT: 0)!
}
extension Formatter {
    static let date = DateFormatter()
}

extension Date {
    func localizedDescription(dateStyle: DateFormatter.Style = .medium,
                              timeStyle: DateFormatter.Style = .medium,
                           in timeZone : TimeZone = .current,
                              locale   : Locale = .current) -> String {
        Formatter.date.locale = locale
        Formatter.date.timeZone = timeZone
        Formatter.date.dateStyle = dateStyle
        Formatter.date.timeStyle = timeStyle
        return Formatter.date.string(from: self)
    }
    var localizedDescription: String { localizedDescription() }
}

Date().localizedDescription                                                // "Sep 26, 2018 at 12:03:41 PM"
Date().localizedDescription(in: .gmt)                                      // "Sep 26, 2018 at 3:03:41 PM" UTC TIME
Date().localizedDescription(dateStyle: .short, timeStyle: .short)          //  "9/26/18, 12:03 PM"
Date().localizedDescription(dateStyle: .full, timeStyle: .full)            //  "Wednesday, September 26, 2018 at 12:03:41 PM Brasilia Standard Time"
Date().localizedDescription(dateStyle: .full, timeStyle: .full, in: .gmt)  // "Wednesday, September 26, 2018 at 3:03:41 PM Greenwich Mean Time"

extension Date {

    var fullDate: String   { localizedDescription(dateStyle: .full,   timeStyle: .none) }
    var longDate: String   { localizedDescription(dateStyle: .long,   timeStyle: .none) }
    var mediumDate: String { localizedDescription(dateStyle: .medium, timeStyle: .none) }
    var shortDate: String  { localizedDescription(dateStyle: .short,  timeStyle: .none) }

    var fullTime: String   { localizedDescription(dateStyle: .none,   timeStyle: .full) }
    var longTime: String   { localizedDescription(dateStyle: .none,   timeStyle: .long) }
    var mediumTime: String { localizedDescription(dateStyle: .none,   timeStyle: .medium) }
    var shortTime: String  { localizedDescription(dateStyle: .none,   timeStyle: .short) }

    var fullDateTime: String   { localizedDescription(dateStyle: .full,   timeStyle: .full) }
    var longDateTime: String   { localizedDescription(dateStyle: .long,   timeStyle: .long) }
    var mediumDateTime: String { localizedDescription(dateStyle: .medium, timeStyle: .medium) }
    var shortDateTime: String  { localizedDescription(dateStyle: .short,  timeStyle: .short) }
}

print(Date().fullDate)  // "Friday, May 26, 2017\n"
print(Date().shortDate)  // "5/26/17\n"

print(Date().fullTime)  // "10:16:24 AM Brasilia Standard Time\n"
print(Date().shortTime)  // "10:16 AM\n"

print(Date().fullDateTime)  // "Friday, May 26, 2017 at 10:16:24 AM Brasilia Standard Time\n"
print(Date().shortDateTime)  // "5/26/17, 10:16 AM\n"