How to change language in kotlin (locale)

Question

I have 2 string files "en" and "tr". When I change my telephone's language string files change automatically(I didn't write extra code for this result and I don't know how this happen). I want change string files with programmatically. I used this code. I get Toast message but language doesn't change.WHY? I used these code before for another application which I write with java not Kotlin and these code work fine. Please don't say duplicate because I read a lot of questions. I try a lot of things until now 4 hours.

override fun onResume() {

        buttonDate()
        changeLanguage()
    super.onResume()
    }
fun changeLanguage(){
        val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(applicationContext)
        val language = sharedPreferences.getString("language","bak")
        Toast.makeText(applicationContext,language,Toast.LENGTH_SHORT).show()
        if(language=="English"){
            Toast.makeText(applicationContext,"English",Toast.LENGTH_SHORT).show()
            language("")
        }else if(language=="Turkish"){
            Toast.makeText(applicationContext,"Turkish",Toast.LENGTH_SHORT).show()
            language("tr")
        }
    }


    fun language(language: String){
        val locale = Locale(language)
        Locale.setDefault(locale)
        val resources = getResources()
        val configuration = resources.getConfiguration()
        configuration.locale = locale
        resources.updateConfiguration(configuration, resources.getDisplayMetrics())
    }

First of all you are get your device language using this code Locale.getDefault().getDisplayLanguage(); — Mayur, May 22 '19 at 05:23
Try this link for change language. https://stackoverflow.com/questions/56057127/language-not-changing-in-app-android-studio/56057774#56057774 — Mayur, May 22 '19 at 05:26
I try this link but it didn't work for me. Maybe I can't I don't know — Hacettepe Hesabı, May 22 '19 at 11:46
Does this answer your question? [Change app language programmatically in Android](https://stackoverflow.com/questions/2900023/change-app-language-programmatically-in-android) — Heitor Paceli, Feb 17 '22 at 02:28
documentation: https://developer.android.com/guide/playcore/feature-delivery/on-demand#lang_resources If you are using App bundles, the app will run ONLY with the necessary resources, so language resources other than the default wont be downloaded unless they are present in the user's phone settings. To enable additional languages while using app bundles, you should implement the Play Feature Delivery Library. follow the steps in the documentation to achieve this! — Saiful Sazib, May 27 '23 at 05:35

score 8 · Accepted Answer · edited May 23 '19 at 16:50

8

You need to update configuration even before onCreate is called. To do that create a BaseActivity class like this

open class BaseActivity : AppCompatActivity() {

    companion object {
        public var dLocale: Locale? = null
    }

    init {
        updateConfig(this)
    }

    fun updateConfig(wrapper: ContextThemeWrapper) {
        if(dLocale==Locale("") ) // Do nothing if dLocale is null
            return

        Locale.setDefault(dLocale)
        val configuration = Configuration()
        configuration.setLocale(dLocale)
        wrapper.applyOverrideConfiguration(configuration)
    }
}

Extend you activities from this class.

Set dLocale in you App class like this:

class App : Application() {

    override fun onCreate() {
        super.onCreate()

        var change = ""
        val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this)
        val language = sharedPreferences.getString("language", "bak")
        if (language == "Turkish") {
            change="tr" 
        } else if (language=="English" ) {
            change = "en"
        }else {
            change ="" 
        } 

        BaseActivity.dLocale = Locale(change) //set any locale you want here
    }
}

You will also need to set App class in your manifest file like this:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">
    //..

    <application
        android:name=".App"
        //..>

    </application>
</manifest>

Note: We should set dLocale only in App onCreate to ensure that all activities have same language.

edited May 23 '19 at 16:50

Hacettepe Hesabı

176
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answered May 22 '19 at 07:00

ahsanali274

471
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14

Thank you. This answer is work. But how can I add my locale with programatically. If I add `private val dLocale: Locale? = Locale("tr")` this work. But how can I add multiple language. – Hacettepe Hesabı May 22 '19 at 14:47
If I use this ```var change = "" val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(wrapper) val language = sharedPreferences.getString("language", "bak") if (language == "Turkish") { change="tr" } else{ } val dLocale: Locale? = Locale(change)``` get null point exception error because of `PreferenceManager.getDefaultSharedPreferences(wrapper)` – Hacettepe Hesabı May 22 '19 at 15:10
1

I have updated my answer. Let me know if you still have any problem. – ahsanali274 May 23 '19 at 06:49
Thank you very much. Your answer really helpfull and work. I edit your code in class App `...if (language=="Turkish") {change="tr"} else if(language=="English") {change="en"} else{ change = "" }... ` and in class BaseActivity `...if(dLocale==Locale(""))...` . dLocale cannot be null because of I define it in App class – Hacettepe Hesabı May 23 '19 at 12:47
May I ask a further Question. I have two more problem now. When I change the language, activity label doesn't change which I define at manifest file as `android:label="@string/settings"`. And second problem : When I change language I must restart my application. If I don't restart, language doesn't change. How I solve this problems. – Hacettepe Hesabı May 23 '19 at 12:53
1

You can use `setTitle(getString(R.string.settings))` in `onCreate` of activity to update label. As for your second question, you can set `dLocale` from anywhere you want but you will need to restart you current activity and all other activities in **back stack** to update their language. So the better choice would be to restart you App for consistency. – ahsanali274 May 23 '19 at 15:02

score 0 · Answer 2 · edited Jul 18 '23 at 07:17

0

Also make sure your res folder should not contain more than one -. For example values-km. It should not be values-km-rKH. It took so long time find and fix this.

edited Jul 18 '23 at 07:17

RusArtM

1,116
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answered Jul 13 '23 at 12:16

Satheesh Sakthivel

11
1

This does not provide an answer to the question. Once you have sufficient [reputation](https://stackoverflow.com/help/whats-reputation) you will be able to [comment on any post](https://stackoverflow.com/help/privileges/comment); instead, [provide answers that don't require clarification from the asker](https://meta.stackexchange.com/questions/214173/why-do-i-need-50-reputation-to-comment-what-can-i-do-instead). - [From Review](/review/late-answers/34684816) – Bö macht Blau Jul 18 '23 at 19:44

How to change language in kotlin (locale)

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