Allows easy iteration about all available locales. Kotlin Collection implementation for LocaleList which doesn't implement Collection<Locale> itself.

Locale.kt

package com.pascalwelsch.android.util

import android.content.Context
import androidx.core.os.ConfigurationCompat
import androidx.core.os.LocaleListCompat
import java.util.Locale

/**
 * Returns an [Iterable] for the languages of the user, sorted by priority. First choice first.
 */
fun Context.userLocales(): Iterable<Locale> {
    return ConfigurationCompat.getLocales(resources.configuration).asIterable()
}

fun LocaleListCompat.asIterable(): Iterable<Locale> = LocaleIterable(this)

private class LocaleIterable(private val localList: LocaleListCompat) : Iterable<Locale> {
    override fun iterator(): Iterator<Locale> = LocaleIterator(localList)
}

private class LocaleIterator(private val localList: LocaleListCompat) : Iterator<Locale> {
    var i = -1
    override fun hasNext(): Boolean = (i + 1) < localList.size()

    override fun next(): Locale {
        if (!hasNext()) throw NoSuchElementException()
        i++
        return localList.get(i)
    }
}

Usage:

fun userSpeaksGerman(): Boolean {
    val germanLocale = context!!.userLocales()
            .firstOrNull { it.language == "de" }
    return germanLocale != null
}

I guess

override fun hasNext(): Boolean = localList.size() < (i + 1)

should be

override fun hasNext(): Boolean = localList.size() > (i + 1)

Thanks @tobltobs, I updated it