For an Android app, I need to parse date in Thai local format (as like, year 2019 should be returned as 2562). I do not understand how can I do so. Currently using SimpleDateFormatter to parse the date in default local format.

fun adjustTimePattern(dateString: String, oldPattern: String, newPattern: String): String? {
    val dateFormat = SimpleDateFormat(oldPattern, Locale.getDefault())
    dateFormat.timeZone = TimeZone.getTimeZone("UTC")
    return try {
        val calendar = Calendar.getInstance()
        calendar.time = dateFormat.parse(dateString)
        val newFormat = SimpleDateFormat(newPattern, Locale.getDefault())
        newFormat.format(calendar.time)
    } catch (e: ParseException) {
        return null
    }
}

Tried to hardcode the value of locale (used Locale("th", "TH") instead of Locale.getDefault()), but got luck since SimpleDateFormat class uses Gregorian Calendar itself.

Have tried to use LocalDate & DateTimeFormatter as well, but the year value doesn't change by any means.

fun formatTime(pattern: String): String {
    return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        val formatter = DateTimeFormatter.ofPattern(pattern, Locale("th", "TH"))
        LocalDate.now().format(formatter)
    } else {
        ""
    }
}

.

Can anyone help me out on this?

ThaiBuddhistDate class

You can use a java.time.chrono.ThaiBuddhistDate to get this done, see the following example:

public static void main(String[] args) throws ParseException {
    ThaiBuddhistDate tbd = ThaiBuddhistDate.now(ZoneId.systemDefault());
    System.out.println(tbd.format(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
}

The output I get on my system is

2562-10-24

Most java.time functionality is back-ported to Java 6 & Java 7 in the ThreeTen-Backport project. Further adapted for earlier Android (<26) in ThreeTenABP. See How to use ThreeTenABP….