compose-localization

Localization for jetpack-compose via CompositionLocalProvider. Thank to CompositionLocalProvider localization can be changed dynamically in runtime.

For speed up runtime it uses ksp to generate resource-files from localization json during compilation. But also localization resources can be loaded in runtime from network, cache, file system.

For example extension for loading resources from assets

fun ILocalization.loadFromRawRes(context: Context, locale: Locale, @RawRes resId: Int) {
    val text = context.resources.openRawResource(resId).bufferedReader().use { it.readText() }
    val json = Json.parseToJsonElement(text).jsonObject
    this.add(JsonResource(locale, json))
}

Setup:

1. In your app module set projectDir

ksp {
    arg("translationsDir", "${projectDir}")
}

2. add id 'com.google.devtools.ksp'
3. add your localization resources in assets or any other res folder example

Example of localization file:

{
  "level1": {
    "level2": {
      "title": "Пора обновить приложение",
      "nutritionValues": "Пищевая ценность на {{grams}} г",
      "key2": "Больше {{1}} кг, но меньше {{2}} кг",
      "reviewsCount_one": "{{count}} оценка — {{retailerName}}",
      "reviewsCount_few": "{{count}} оценки — {{retailerName}}",
      "reviewsCount_many": "{{count}} оценок —  {{retailerName}}",
      "reviewsCount_other": "{{count}} оценок —  {{retailerName}}"
    }
  }
}

4. annotate your localization classes Translation annotation. This annotation will generate localization classes with Locale and map of strings according passed lang and json

@Translation(lang = "ru", path = "src/main/assets/ru.json")
class RuResource

@Translation(lang = "en", path = "src/main/assets/en.json")
class EnResource

5. create localization instance

val localization =
    Localization(GeneratedRuResource) // GeneratedRuResource - generated class by @Translation

// resources can be added later
localization.add(GeneratedEnResource)

You can get translation via t method

val traslatedkey = localization.get().t("level1.level2.title") // -> "Пора обновить приложение"
val traslatedkey =
    localization.get(Locale.ENGLISH).t("level1.level2.title") // -> "It is time to update the app"

It also supports string formatting

localization.get()
    .t("level1.level2.nutritionValues", mapOf("grams" to 100)) // -> "Пищевая ценность на 100 г"
localization.get().t(
    "level1.level2.key2",
    mapOf("1" to 1000.99, "2" to 100999.999)
) // -> "Больше 1000,00 кг, но меньше 9999,99 кг"

Pluralism also works

localization.get(Locale.ENGLISH).t(
    "level1.level2.reviewsCount",
    mapOf("count" to 0, "retailerName" to "Shop1"),
    plural = "count"
) // -> "0 reviews - Shop1"
localization.get(Locale.ENGLISH).t(
    "level1.level2.reviewsCount",
    mapOf("count" to 1, "retailerName" to "Shop2"),
    plural = "count"
) // -> "1 review - Shop2"
localization.get(Locale.ENGLISH).t(
    "level1.level2.reviewsCount",
    mapOf("count" to 5, "retailerName" to "Shop3"),
    plural = "count"
) // -> "5 reviews - Shop3"

It can be used in jetpack-compose

import com.example.localization_compose.LocalizationProvider
import com.example.localization.Localization
import com.example.localization_compose.t

private val RU = Locale("ru")

@Composable
fun Content() {
    val (locale, setLocale) = remember { mutableStateOf(RU) }
    val localization = remember { Localization(GeneratedRuResource).add(GeneratedEnResource) }
    LocalizationProvider(localization, lang = locale.language) {
        Column() {
            Text(text = t("level1.level2.title"))
            Text(text = t("level1.level2.nutritionValues", 100)) 
            Text(text = t("level1.level2.nutritionValues", mapOf("grams" to 100)))
            Text(text = t("level1.level2.key2", mapOf("1" to 1000.99, "2" to 100999.999)))
            Text(
                text = t(
                    "level1.level2.reviewsCount",
                    mapOf("count" to 0, "retailerName" to "Shop1"),
                    plural = "count"
                )
            )
        }
    }
}

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            Content()
        }
    }
}