localization

name	localization
description	Properly work with localization in Android projects. Use this skill when adding new string resources, working with plurals, formatting dates and texts.

Localization

When to Use

• Use this skill when adding new string resources to the project
• Use this skill when working with plurals
• Use this skill when formatting dates, numbers, or texts
• Use this skill when localizing error messages
• Use this skill when updating existing strings in the project
• This skill is useful when you need to ensure localization consistency across all languages

Instructions

Project Languages

• Russian (ru) - primary language, all strings must be in Russian
• English (en) - additional language, translation must match Russian original

String Resources

Basic rules:

1. All string resources are placed in res/values/strings.xml (Russian) and res/values-en/strings.xml (English)
2. Each string has a unique name in lowercase with underscores
3. Add new strings in parallel to both files (ru and en)

Example of adding a string:

<!-- res/values/strings.xml -->
<string name="welcome_message">Добро пожаловать!</string>

<!-- res/values-en/strings.xml -->
<string name="welcome_message">Welcome!</string>

Usage in code:

context.getString(R.string.welcome_message)
// or in XML
android:text="@string/welcome_message"

Plurals

When to use:

• For words changing form based on quantity (day/days)
• For counters, lists, quantity indicators

Russian language rule:

• one - 1, 21, 31, 41...
• few - 2-4, 22-24, 32-34...
• many - 0, 5-20, 25-30, 35-40...
• other - for all other cases (usually not used in Russian)

Example:

<!-- res/values/strings.xml -->
<plurals name="days_count">
    <item quantity="one">%d день</item>
    <item quantity="few">%d дня</item>
    <item quantity="many">%d дней</item>
    <item quantity="other">%d дней</item>
</plurals>

<!-- res/values-en/strings.xml -->
<plurals name="days_count">
    <item quantity="one">%d day</item>
    <item quantity="other">%d days</item>
</plurals>

Usage in code:

val days = 5
val text = resources.getQuantityString(R.plurals.days_count, days, days)
// Result: "5 дней" (ru) or "5 days" (en)

Formatting

Basic tools:

• String.format() - for formatting strings with placeholders
• MessageFormat - for complex formatting (if needed)
• DateFormat - for dates considering user locale

String formatting example:

<!-- res/values/strings.xml -->
<string name="items_count_format">Найдено %d элементов</string>

<!-- res/values-en/strings.xml -->
<string name="items_count_format">Found %d items</string>

Usage in code:

val count = 42
val text = getString(R.string.items_count_format, count)
// Result: "Найдено 42 элементов"

Date formatting example:

val date = LocalDate.now()
val formatter = DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM)
val formattedDate = date.format(formatter)
// Result depends on device locale

Logging

Important rule: All logs in code are written in Russian regardless of app localization

// Correct
Log.e(TAG, "Ошибка загрузки данных: ${error.message}")
Log.i(TAG, "Загружено $count элементов")

// Incorrect
Log.e(TAG, "Error loading data: ${error.message}")

Resource Organization

String grouping:

• Use prefixes for grouping strings (e.g., auth_, parks_, events_)
• Related strings should have similar names

Grouping example:

<!-- Authorization -->
<string name="auth_login">Войти</string>
<string name="auth_password">Пароль</string>
<string name="auth_forgot_password">Забыли пароль?</string>

<!-- Parks -->
<string name="parks_title">Площадки</string>
<string name="parks_empty">Нет площадок</string>
<string name="parks_filter">Фильтр</string>

Working with Parameters

Rules:

1. Use positional parameters (%1$s, %2$d) for strings with multiple substitutions
2. Keep parameter order the same for all languages

Example with multiple parameters:

<!-- res/values/strings.xml -->
<string name="user_profile">%1$s, %2$d лет</string>

<!-- res/values-en/strings.xml -->
<string name="user_profile">%1$s, %2$d years old</string>

Usage:

val name = "Иван"
val age = 25
val text = getString(R.string.user_profile, name, age)
// Result: "Иван, 25 лет"

Error Handling

Localized error messages:

<!-- Network errors -->
<string name="error_network">Ошибка сети. Проверьте подключение к интернету.</string>
<string name="error_timeout">Время ожидания истекло. Попробуйте еще раз.</string>

<!-- Authorization errors -->
<string name="error_invalid_credentials">Неверный логин или пароль</string>
<string name="error_unauthorized">Необходима авторизация</string>

<!-- Data errors -->
<string name="error_not_found">Данные не найдены</string>
<string name="error_invalid_data">Неверные данные</string>

Usage in code:

try {
    loadData()
} catch (e: IOException) {
    Log.e(TAG, "Ошибка сети: ${e.message}")
    showError(getString(R.string.error_network))
}

Checklist for Adding Localization

1. Added string to res/values/strings.xml (Russian)
2. Added string to res/values-en/strings.xml (English)
3. Checked that name is unique and follows naming convention
4. Used correct format (simple string, plurals, formatting)
5. Checked usage in code or XML
6. Made sure logs are in Russian (if needed)
7. Tested on different device languages (if possible)