> ## Documentation Index
> Fetch the complete documentation index at: https://cometchat-22654f5b-docs-rn-guide-message-privately.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Localize

> Localize CometChat Android UI Kit with supported languages, string resources, locale changes, and app-specific translations.

<Accordion title="AI Integration Quick Reference">
  | Field               | Value                                                                                                      |
  | ------------------- | ---------------------------------------------------------------------------------------------------------- |
  | Package             | `com.cometchat:chat-uikit-android`                                                                         |
  | Import              | `com.cometchat.chatuikit.resources.localize.CometChatLocalize`                                             |
  | Set language        | `CometChatLocalize.setLocale(context, Language.Code.fr)`                                                   |
  | Get language        | `CometChatLocalize.getLocale(context)`                                                                     |
  | Supported languages | 19: ar, de, en, es, fr, hi, hu, it, ja, ko, lt, ms, nl, pt, ru, sv, tr, zh, zh-TW                          |
  | Override labels     | `res/values/strings.xml` — override UI Kit string resource keys                                            |
  | Date formatting     | `DateTimeFormatterCallback` for custom date/time labels                                                    |
  | Related             | [Theme Introduction](/ui-kit/android/theme-introduction) \| [Sound Manager](/ui-kit/android/sound-manager) |
</Accordion>

Set the CometChat UI Kit language and override UI text so your Android app matches your users' locale.

## When to use this

* You want the UI Kit to follow the device language.
* You want to force a specific language regardless of device settings.
* You need to override default UI Kit labels with brand-specific wording.
* You want consistent date and time labels across all UI Kit screens.

## Prerequisites

* CometChat UI Kit for Android is installed and initialized. Use [Getting Started](/ui-kit/android/getting-started) if needed.
* You can access an Android `Context` (Activity or Application) to apply locale changes.
* You can edit `res/values/strings.xml` in your app module.

## Quick start

1. Choose a language code from Supported languages.
2. Add a locale call before you render UI Kit screens.
   File: `app/src/main/java/<your_package>/LocalizeActivity.java` or `app/src/main/java/<your_package>/LocalizeActivity.kt`.
   Use the code in Implementation > Set and read the UI Kit locale.
3. Override UI text keys in `res/values/strings.xml` if you need custom wording.
4. Rebuild and run the app.
5. Verify that UI Kit labels render in the selected language and your custom strings appear.

## Core concepts

* `CometChatLocalize`: Utility class to set and read the UI Kit locale from an Android `Context`.
* `Language.Code`: Constants for supported language codes to use with `setLocale`.
* `strings.xml`: Android string resources that control the visible text in UI Kit components.
* `DateTimeFormatterCallback`: Callback interface to control date and time labels like "Today" or "X mins ago".

### CometChatLocalize methods

* `setLocale(Context context, @Language.Code String language)`: Sets the UI Kit language using a `Language.Code` value.
* `getLocale(Context context)`: Returns the current locale country code for the provided context.

### Supported languages

UI Kit supports 19 languages for localization:

* Arabic (`ar`)
* Chinese (`zh`)
* Chinese (Traditional) (`zh-TW`)
* Dutch (`nl`)
* English (`en`)
* French (`fr`)
* German (`de`)
* Hindi (`hi`)
* Hungarian (`hu`)
* Italian (`it`)
* Japanese (`ja`)
* Korean (`ko`)
* Lithuanian (`lt`)
* Malay (`ms`)
* Portuguese (`pt`)
* Russian (`ru`)
* Spanish (`es`)
* Swedish (`sv`)
* Turkish (`tr`)

## Implementation

### Set and read the UI Kit locale

What you're changing: The UI Kit language for your app session.

* **Where to change it**: Your Activity or Application class before UI Kit screens are rendered.

* **Applies to**: All UI Kit screens.

* **Default behavior**: UI Kit uses the device locale.

* **Override**: Call `CometChatLocalize.setLocale(...)` with a `Language.Code` value.

* **Code**:

<Tabs>
  <Tab title="Kotlin">
    ```kotlin LocalizeActivity.kt lines theme={null}
    import android.os.Bundle
    import androidx.appcompat.app.AppCompatActivity
    import com.cometchat.chatuikit.shared.resources.localise.CometChatLocalize
    import com.cometchat.chatuikit.shared.resources.localise.Language

    class LocalizeActivity : AppCompatActivity() {
        override fun onCreate(savedInstanceState: Bundle?) {
            super.onCreate(savedInstanceState)

            CometChatLocalize.setLocale(this, Language.Code.hi)
            val currentLocale = CometChatLocalize.getLocale(this)

            setContentView(R.layout.activity_localize)
        }
    }
    ```
  </Tab>

  <Tab title="Java">
    ```java LocalizeActivity.java lines theme={null}
    import android.os.Bundle;
    import androidx.appcompat.app.AppCompatActivity;
    import com.cometchat.chatuikit.shared.resources.localise.CometChatLocalize;
    import com.cometchat.chatuikit.shared.resources.localise.Language;

    public class LocalizeActivity extends AppCompatActivity {
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);

            CometChatLocalize.setLocale(this, Language.Code.hi);
            String currentLocale = CometChatLocalize.getLocale(this);

            setContentView(R.layout.activity_localize);
        }
    }
    ```
  </Tab>
</Tabs>

* **What this does**: Sets the UI Kit language to Hindi for the current context and reads the current locale value for later use.

* **Verify**: Launch a UI Kit screen and confirm labels display in the selected language.

### Override UI Kit strings in `strings.xml`

What you're changing: Visible text used by UI Kit components.

* **Where to change it**: `app/src/main/res/values/strings.xml` in your app module.

* **Applies to**: All UI Kit components that reference the string key.

* **Default behavior**: UI Kit uses its internal `strings.xml` values.

* **Override**: Add the same key to your app's `strings.xml` to override the label.

Example reference from UI Kit `strings.xml`:

<Frame>
  <img src="https://mintcdn.com/cometchat-22654f5b-docs-rn-guide-message-privately/NN4EdpOU3viwWMb_/images/09c92298-conversation_string_customization-4bd4560358557075106f65db69aa231c.png?fit=max&auto=format&n=NN4EdpOU3viwWMb_&q=85&s=c6fcaf20ba1282f19cb3dda12f16c3be" width="1280" height="800" data-path="images/09c92298-conversation_string_customization-4bd4560358557075106f65db69aa231c.png" />
</Frame>

```xml strings.xml lines theme={null}
<resources>
   <string name="cometchat_chats" translatable="true">Chats</string>
   ....
</resources>
```

* **What this does**: Shows the default UI Kit label for the conversations list.

Override the key in your app:

```xml res/values/strings.xml lines theme={null}
<resources>
   <string name="cometchat_chats" translatable="true">Conversations</string>
   ....
</resources>
```

* **What this does**: Replaces the UI Kit label with your custom text.

Why use this approach:

* No UI Kit source code changes required.
* Easy localization using Android resources.
* UI Kit updates do not overwrite your overrides.
* You can tailor text without affecting behavior.

### Customize date and time labels

What you're changing: Global time and date labels such as "Today", "Yesterday", and "X mins ago".

* **Where to change it**: Your UI Kit initialization (where you build `UIKitSettings`).

* **Applies to**: All UI Kit screens that display timestamps.

* **Default behavior**: UI Kit uses its built-in formatter.

* **Override**: Provide a `DateTimeFormatterCallback` when building `UIKitSettings`.

* **Code**:

<Tabs>
  <Tab title="Kotlin">
    ```kotlin AppInit.kt lines theme={null}
    import android.content.Context
    import android.util.Log
    import com.cometchat.chat.core.CometChat
    import com.cometchat.chat.exceptions.CometChatException
    import com.cometchat.chatuikit.shared.cometchatuikit.CometChatUIKit
    import com.cometchat.chatuikit.shared.cometchatuikit.UIKitSettings
    import com.cometchat.chatuikit.shared.interfaces.DateTimeFormatterCallback
    import java.text.SimpleDateFormat
    import java.util.Date
    import java.util.Locale

    object AppInit {
        fun initUiKitWithDateFormatter(
            context: Context,
            appId: String,
            region: String,
            authKey: String
        ) {
            val uiKitSettings = UIKitSettings.UIKitSettingsBuilder()
                .setAppId(appId)
                .setRegion(region)
                .setDateTimeFormatterCallback(object : DateTimeFormatterCallback {

                    private val fullTimeFormatter = SimpleDateFormat("hh:mm a", Locale.getDefault())
                    private val dateFormatter = SimpleDateFormat("dd MMM yyyy", Locale.getDefault())

                    override fun time(timestamp: Long): String {
                        return fullTimeFormatter.format(Date(timestamp))
                    }

                    override fun today(timestamp: Long): String {
                        return "Today"
                    }

                    override fun yesterday(timestamp: Long): String {
                        return "Yesterday"
                    }

                    override fun lastWeek(timestamp: Long): String {
                        return "Last Week"
                    }

                    override fun otherDays(timestamp: Long): String {
                        return dateFormatter.format(Date(timestamp))
                    }

                    override fun minutes(diffInMinutesFromNow: Long, timestamp: Long): String {
                        return "$diffInMinutesFromNow mins ago"
                    }

                    override fun hours(diffInHourFromNow: Long, timestamp: Long): String {
                        return "$diffInHourFromNow hrs ago"
                    }
                })
                .setAuthKey(authKey)
                .build()

            CometChatUIKit.init(context, uiKitSettings, object : CometChat.CallbackListener<String>() {
                override fun onSuccess(s: String) {
                    Log.d("CometChatInit", "Success: $s")
                }

                override fun onError(e: CometChatException) {
                    Log.e("CometChatInit", "Error: ${e.message}")
                }
            })
        }
    }
    ```
  </Tab>

  <Tab title="Java">
    ```java AppInit.java lines theme={null}
    import android.content.Context;
    import android.util.Log;
    import com.cometchat.chat.core.CometChat;
    import com.cometchat.chat.exceptions.CometChatException;
    import com.cometchat.chatuikit.shared.cometchatuikit.CometChatUIKit;
    import com.cometchat.chatuikit.shared.cometchatuikit.UIKitSettings;
    import com.cometchat.chatuikit.shared.interfaces.DateTimeFormatterCallback;
    import java.text.SimpleDateFormat;
    import java.util.Date;
    import java.util.Locale;

    public class AppInit {
        public static void initUiKitWithDateFormatter(
            Context context,
            String appId,
            String region,
            String authKey
        ) {
            UIKitSettings uiKitSettings = new UIKitSettings.UIKitSettingsBuilder()
                .setAppId(appId)
                .setRegion(region)
                .setDateTimeFormatterCallback(new DateTimeFormatterCallback() {

                    private final SimpleDateFormat fullTimeFormatter = new SimpleDateFormat("hh:mm a", Locale.getDefault());
                    private final SimpleDateFormat dateFormatter = new SimpleDateFormat("dd MMM yyyy", Locale.getDefault());

                    @Override
                    public String time(long timestamp) {
                        return fullTimeFormatter.format(new Date(timestamp));
                    }

                    @Override
                    public String today(long timestamp) {
                        return "Today";
                    }

                    @Override
                    public String yesterday(long timestamp) {
                        return "Yesterday";
                    }

                    @Override
                    public String lastWeek(long timestamp) {
                        return "Last Week";
                    }

                    @Override
                    public String otherDays(long timestamp) {
                        return dateFormatter.format(new Date(timestamp));
                    }

                    @Override
                    public String minutes(long diffInMinutesFromNow, long timestamp) {
                        return diffInMinutesFromNow + " mins ago";
                    }

                    @Override
                    public String hours(long diffInHourFromNow, long timestamp) {
                        return diffInHourFromNow + " hrs ago";
                    }
                })
                .setAuthKey(authKey)
                .build();

            CometChatUIKit.init(context, uiKitSettings, new CometChat.CallbackListener<String>() {
                @Override
                public void onSuccess(String s) {
                    Log.d("CometChatInit", "Success: " + s);
                }

                @Override
                public void onError(CometChatException e) {
                    Log.e("CometChatInit", "Error: " + e.getMessage());
                }
            });
        }
    }
    ```
  </Tab>
</Tabs>

* **What this does**: Registers a global `DateTimeFormatterCallback` so all UI Kit timestamps use your formatting rules.

* **Verify**: Open a conversation list and confirm labels like "Today" or "X mins ago" match your formatter.

For the full callback reference, see [CometChatUIKit methods: DateFormatter](/ui-kit/android/methods#dateformatter).

## Customization matrix

| What you want to change         | Where                                                    | Property/API                                          | Example                                                                     |
| ------------------------------- | -------------------------------------------------------- | ----------------------------------------------------- | --------------------------------------------------------------------------- |
| UI Kit language (global)        | `app/src/main/java/<your_package>/LocalizeActivity.java` | `CometChatLocalize.setLocale(Context, Language.Code)` | `CometChatLocalize.setLocale(this, Language.Code.hi);`                      |
| Read current locale (optional)  | `app/src/main/java/<your_package>/LocalizeActivity.java` | `CometChatLocalize.getLocale(Context)`                | `String currentLocale = CometChatLocalize.getLocale(this);`                 |
| UI Kit label text (strings.xml) | `app/src/main/res/values/strings.xml`                    | `cometchat_chats`                                     | `<string name="cometchat_chats" translatable="true">Conversations</string>` |
| Global date and time labels     | `app/src/main/java/<your_package>/AppInit.java`          | `setDateTimeFormatterCallback(...)`                   | `.setDateTimeFormatterCallback(new DateTimeFormatterCallback() {`           |