如何将UIDatePicker设置为始终为UTC时间和日期，忽略夏令时

Question

UIDatePicker我想将UIDatePicker设置为始终具有UTC时间和日期，忽略任何本地时间和夏令时。在我的应用程序UIDatePicker 2019年3月31日之后如果我将在文本字段中设置时间02:00它将显示03:00。

`func createDatePicker()  {
    datePicker = UIDatePicker()
    datePicker?.datePickerMode = .dateAndTime
    datePicker?.timeZone = NSTimeZone(name: "GMT")! as TimeZone

    datePicker?.timeZone = TimeZone(secondsFromGMT: 0)

    datePicker?.setValue(UIColor.white, forKey: "textColor")
    datePicker?.backgroundColor = UIColor.black.withAlphaComponent(0.6)

datePicker?.minimumDate = Date.calculateDate(day: 1, month: 1, year: 2019, hour: 0, minute: 0)
datePicker?.maximumDate = Date.calculateDate(day: 1, month: 1, year: 2020, hour: 0, minute: 0)




    // create toll bar
    let toolBar = UIToolbar()
    toolBar.sizeToFit()
    toolBar.barStyle = .blackOpaque

    //add done botton on this tool bar
    let doneBotton = UIBarButtonItem(barButtonSystemItem: .done, target: nil, action: #selector(doneDateClicked))
    toolBar.setItems([doneBotton], animated: true)
    doneBotton.style = .done
    dateTextField.inputAccessoryView = toolBar


    dateTextField.inputView = datePicker
}`

Answer 1

您可以使用以下函数来获取可能需要应用的偏移量来校正夏令时。

datePicker?.timeZone.daylightSavingTimeOffset(for: Date)

返回给定日期的夏令时偏移量。

参数

date：用于计算的日期。默认值是当前日期。

See Apple Documentation.