Is the calendaring system needed for China supported in Qt?
No, right now it only support "Julian", "Islamic Civil", "Jalali", "Milankovic", "Persian", "Islamic", "islamic-civil", "islamicc", "gregory", "Gregorian". Adding a custom calendar system requires subclass QCalendarBackend which is a private Qt API. I also think there are some issue in the QCalendar API design. For example, it only provide a way to check if the year is a leap year, but not possible to know if a month is leap month. Also we cannot get the display name of a day (the 1st day of a month names "初一", I haven't found the API which can get the localized day name for this need). While I doing resources about calendar systems, I found the icu4c's implementation is much better, but I don't know much about different calendar systems so I'm not sure about if it's I didn't fully understand the QCalendar API or is QCalendar API actually missing something which need to be added. Please also take a look at https://docs.google.com/document/d/1iwEwwK9w34ZKOegb8xcecO4u2Pjgv2e7ifXMFKox62Q/edit?usp=sharing and https://bugs.kde.org/show_bug.cgi?id=429892 which also have some other additional information which might useful on this topic :)
This class is new as of Qt 5.14, so we couldn't depend on it yet.
Yeah, and also, the QCalendar class doesn't come with chinese lunar calendar system support, so if subclassing QCalendarBackend (private API) is not acceptable, then we may need wait longer to make such feature land into KDE. So I suggest we can create a plugin API to add alternate calendar support, and plugin writer can use whatever libs they want for their alternate calendar implementation. If we do that, this feature itself will also not rely on a specific Qt version.
If the Chinese calendar support needs to be added in Qt, I suggest to contact developers at the Qt development mailing list.
Will try to send a mail later. I'm still pretty new to mailing list and not sure about how to use it properly XD Gary
