Using java.time classes in older Android, such as DayOfWeek

Question

The application I'm working on is related to the weekly calendar.

I want to fetch the days of the week. The code below for this is fully working. But I have to lower the API level of the project to 26 -> 24. Thus, some codes become inoperable at API 24 level.

How can I go about this in an alternative way?

My Code:

fun daysOfWeekFromLocale(): Array<DayOfWeek> {

val firstDayOfWeek = WeekFields.of(Locale.getDefault()).firstDayOfWeek
var daysOfWeek = DayOfWeek.values()

if (firstDayOfWeek != DayOfWeek.MONDAY) {
    val rhs = daysOfWeek.sliceArray(firstDayOfWeek.ordinal..daysOfWeek.indices.last)
    val lhs = daysOfWeek.sliceArray(0 until firstDayOfWeek.ordinal)
    daysOfWeek = rhs + lhs
}

return daysOfWeek
}

Android studio's Red Lines:

Function Image

(In all cases this function should return the same value. -- Array< DayOfWeek > )

Answer 1

API “de-sugaring”

The latest Android tooling brings to earlier Android most of the java.time functionality built into Android 26+ via “API desugaring”.

Three-TenABP

If that does not work for you, use the ThreeTenABP library, an Android-specific adaptation of ThreeTen-Backport.

---

For more details, see How to use ThreeTenABP in Android Project. See Answers by kael and by me.