Swift - 如何在默认情况下存储多个日期并检索它？

Question

这是我的代码。我想在用户默认值中保存todayString和nextString，以便我可以在标签中显示存储日期（每周二更新），而不是星期二。

let today = NSDate()
    let nextTue = Calendar.current.date(byAdding: .day, value: 6, to: today as Date)
    let formatter = DateFormatter()
    formatter.dateFormat = "yyyy-MM-dd"
    let todayString = formatter.string(from: today as Date)
    let nextString = formatter.string(from: nextTue!)
    formatter.dateFormat = "dd-MMM-yyyy"

    let calendar = NSCalendar(calendarIdentifier: NSCalendar.Identifier.gregorian)
    let components = calendar!.components([.weekday], from: today as Date)

    if components.weekday == 3 {
        print("Hello Tuesday")
        thisWeekDate.text! = "\(todayString) - \(nextString)"

    } else {
        print("It's not Tuesday")
    }

Answer 1

NSUserDefaults使用设备存储在应用程序运行之间保存数据。

在您的情况下，最简单的方法是保存两个不同的日期对象，或者您可以创建包含两个日期对象的字典并保存它。

存储

UserDefaults.standard.set(todayString, forKey: "todayStringKey")

提取

let RetrivedDate = UserDefaults.standard.object(forKey: "todayStringKey") as? NSDate

删除 - 如果您想从存储中完全删除它

UserDefaults.standard.removeObject(forKey: "todayStringKey")