I use the kotlinx-datetime library to get and compare with the user's current date.
I ran into a problem that:
SomeInstant.toLocalDateTime(TimeZone.currentSystemDefault()).month.name
Returns the name of the month in English, for example: January.
How can I change the month name for the user's locale? For example, janvier in French.
I want to use this library only, without resorting to java.time classes on the Java platform.
There's an open discussion about on GitHub about how to provide localized date-time formats. For now, a complete solution isn't possible in pure Kotlin.
If you want the ability to format dates for any user in any language, you'll need to rely on the tools from Android, Java, or whatever other platform you're running on.
However, if you know where your users are from, you do have some options. When building a DateTimeFormat, you can supply your own list of MonthNames.
val instant = Clock.System.now()
val localDateTime = instant.toLocalDateTime(TimeZone.currentSystemDefault())
val frenchMonths = listOf(
"janvier", "février", "mars", "avril", "mai", "juin",
"juillet", "aout", "septembre", "octobre", "novembre", "décembre"
)
val format = LocalDateTime.Format {
dayOfMonth()
char(' ')
monthName(MonthNames(frenchMonths))
}
println(format.format(localDateTime)) // 30 juillet
You'd need to do this separately for each language that you want to support, unless you can find somewhere to get them programmatically.
Of course, one place to get a list of month names would be from Java. You said you don't want to resort to java.time classes at all, but what about a hybrid approach? Java can provide the month names, and Kotlin can do the formatting.
In common code:
expect fun getMonthNames(languageTag: String): List<String>
val frenchMonths = getMonthNames("fr")
val format = LocalDateTime.Format {
dayOfMonth()
char(' ')
monthName(MonthNames(frenchMonths))
}
And on the JVM:
actual fun getMonthNames(languageTag: String): List<String> {
val locale = Locale.forLanguageTag(languageTag)
val symbols = DateFormatSymbols.getInstance(locale)
return symbols.months.take(12)
}
I've faced similar issue and the easiest way to handle it using Map, simply use a names of months in English as key and French months as value, can take it a step further use map of maps if you have multiple languages.
Map<String, List<String>. Use the first entry as en: [fr, hn, ru], similar to index of an array, and use rest of the entries for translation. Not sure if it's any better or even if it's better than previous solutions, but it gives you a nice way to iterate through same month name for different languages, if you need to use in any table or similar areas. Using first one as index can also double as actual index if you wanna use month numbers instead of their english names, just put 0 at start and begin with 1 at janfun Month.toCurrentLocale(language: String): String { return mapMonths[language]?.get(ordinal) ?: mapMonths["en"]!![ordinal] }