使用日文日历时，iOS 15上的UIDatePicker会停止显示era

Question

我的UIDatePicker使用公历或用户选择的其他日历。当他们选择日历时，拾取器会像这样显示纪元年份："平成30年“或”令和2年“。

在iOS 14之前，它一直工作得很好。现在在iOS 15上，它只是"30“或"2”。这是一个bug吗，或者有没有办法修复它，这样时代就会在年份之前显示出来？

我使用以下代码在我的应用程序上重新加载UIDatePicker。

func reloadPickers() -> Void { 
    
    var title = timeZone?.localizedName(for: .standard, locale: locale)
    if (timeZone?.isDaylightSavingTime(for: dateTimeComplete!))! {
        title = timeZone?.localizedName(for: .daylightSaving, locale: locale)
    } else {
    }
    buttonTimeZone.setTitle(title, for: .normal)

    let originalDateSecondsOnly = NSCalendar.current.dateComponents([.second], from: dateTimeComplete!)

    secondPickerView.reloadAllComponents()
    if arraySeconds?.count != 0 {
        secondPickerView.selectRow(second, inComponent: 0, animated: false)
    }
    
    let components = calendar.dateComponents([.era, .year, .month, .day, .hour, .minute], from: dateTimeComplete!)
    let dateWithoutSecond = calendar.date(from: components)

    datePicker.date     = dateWithoutSecond!
    datePicker.timeZone = timeZone!
    datePicker.calendar = calendar
    datePicker.locale   = locale
    datePicker.addTarget(self, action: #selector(DateChooserViewController.dateUpdated), for: .valueChanged)
    
    timePicker.date     = dateWithoutSecond!
    timePicker.timeZone = timeZone!
    timePicker.calendar = calendar
    timePicker.locale   = locale
    timePicker.addTarget(self, action: #selector(DateChooserViewController.timeUpdated), for: .valueChanged)
    
}


@IBAction func switchCalendarButtonTapped(_ sender: Any) { //ver2.0.4
    
    print("switchCalendarButtonTapped")
    
    if let alternateCalendar = UserDefaults.standard.value(forKey: "alternateCalendar") as? String {
        
        if useAlternateCalendar {
            useAlternateCalendar = false
            calendar = Calendar.current
            reloadPickers()
        } else {
            switch alternateCalendar {
            case "buddhist":
                calendar = Calendar.init(identifier: .buddhist)
            case "chinese":
                calendar = Calendar.init(identifier: .chinese)
            case "coptic":
                calendar = Calendar.init(identifier: .coptic)
            case "ethiopicAmeteAlem":
                calendar = Calendar.init(identifier: .ethiopicAmeteAlem)
            case "ethiopicAmeteMihret":
                calendar = Calendar.init(identifier: .ethiopicAmeteMihret)
            case "gregorian":
                calendar = Calendar.init(identifier: .gregorian)
            case "hebrew":
                calendar = Calendar.init(identifier: .hebrew)
            case "indian":
                calendar = Calendar.init(identifier: .indian)
            case "islamic":
                calendar = Calendar.init(identifier: .islamic)
            case "islamicCivil":
                calendar = Calendar.init(identifier: .islamicCivil)
            case "islamicTabular":
                calendar = Calendar.init(identifier: .islamicTabular)
            case "islamicUmmAlQura":
                calendar = Calendar.init(identifier: .islamicUmmAlQura)
            case "japanese":
                calendar = Calendar.init(identifier: .japanese)
            case "persian":
                calendar = Calendar.init(identifier: .persian)
            case "republicOfChina":
                calendar = Calendar.init(identifier: .republicOfChina)
            default:
                print("do nothing")
            }
            useAlternateCalendar = true
            reloadPickers()
            
            if !(UIApplication.shared.delegate as! AppDelegate).canUseTimeCalculation() { //ver2.0.6
                let alert = UIAlertController(title: NSLocalizedString("Please Upgrade", comment: ""), message: NSLocalizedString("Please upgrade to enable this function.", comment: ""), preferredStyle: .alert)
                alert.addAction(UIAlertAction(title: NSLocalizedString("Upgrade", comment: ""), 
                                              style: .default,
                                              handler: {
                                                (action: UIAlertAction!) -> Void in
                                                print("Upgrade is pressed")
                                                self.useAlternateCalendar = false
                                                self.calendar = Calendar.current
                                                self.reloadPickers()
                                                self.openInAppPurchaseForTimeCalcVC(forFree: false)
                }))
                alert.addAction(UIAlertAction(title: NSLocalizedString("Cancel", comment: ""),
                                              style: .cancel,
                                              handler: {
                                                (alert: UIAlertAction!) in
                                                print("Cancel is pressed")
                                                self.useAlternateCalendar = false
                                                self.calendar = Calendar.current
                                                self.reloadPickers()
                }))
                self.show(alert, sender: self)
            } else {
                (presentingViewController as! ViewController).shouldCountNumberOfTimeCalcTrial = true
            }
        }

    } else {
        
        if Locale.current.regionCode == "JP" {
            if Calendar.current.identifier == .gregorian {
                UserDefaults.standard.setValue("japanese", forKey: "alternateCalendar")
            } else {
                UserDefaults.standard.setValue("gregorian", forKey: "alternateCalendar")
            }
            UserDefaults.standard.synchronize()
            switchCalendarButtonTapped(self)
        } else {
            changeAlternateCalendar()
        }
    }
            
}

Answer 1

我在使用UIDatePicker的中国日历时也遇到了同样的问题，但我发现，在iOS 15的“手机”应用程序中，用于设置联系人生日的UIDatePicker显示正常。

我发现这个UIDatePicker的locale属性设置如下：

Locale(identifier: "zh_CN@calendar=chinese")

因此，我假设您应该将其设置为：

let identifier = Locale.autoupdatingCurrent.identifier + "@calendar=chinese"
datePicker.locale = Locale(identifier: identifier)

在我的iOS 15设备上显示"平成30年“和"令和2年”。