Rosetta is an Android library that helps Android apps support multiple languages. Using Rosetta, switching between languages won't cause any headaches!

You can use Jcenter() or mavenCentral()

repositories {
    mavenCentral()
}

dependencies {
  compile "com.ahmedjazzar.rosetta:rosetta:1.0.1"
}

At the launch activity or MainApplication.java, the library offers two ways to identify and set the supported locales:

• For the first way, you need to know what languages your app is going to use. This method is predictable, easy to use, and more efficient than the second method. You can use it if your app is closed source or has specific supported locales:

// This is the locale that you wanna your app to launch with.
Locale firstLaunchLocale = new Locale("ar");

// You can use a HashSet<String> instead and call 'setSupportedStringLocales()' :)
HashSet<Locale> supportedLocales = new HashSet<>();
supportedLocales.add(Locale.US);
supportedLocales.add(Locale.CHINA);
supportedLocales.add(firstLaunchLocale);

// You can make the following object static so you can use the same reference in all app's
// classes. static is much stable.
LanguageSwitcher ls = new LanguageSwitcher(this, firstLaunchLocale);
ls.setSupportedLocales(supportedLocales);

• The second way is asking the library to do its magic and search inside the app for available locales. May fail! *:

// This is the locale that you wanna your app to launch with.
Locale firstLaunchLocale = new Locale("ar");

// IMPORTANT: this is the locale of the main strings.xml file. -- most developers write it
// in English, so if you wrote it in another locale specify it here.
Locale baseLocale = Locale.ENGLISH;

// stringId: the id of a string that's occurred in every locale with a different character.
// For instance if you have 3 locales: US, UK, and Arabic the perfect fit would be the word
// 'color' -if exist for sure- because it has different form in each locale:
// Locale.US: color, Locale.UK: colour, ar: لون
int stringId = R.string.nice_string;

LanguageSwitcher ls = new LanguageSwitcher(this, firstLaunchLocale, baseLocale);
ls.setSupportedLocales(stringId);

The second methodology fetches the available locales in your app, then sets them as the support locales (since there are no supported locales provided). by executing the following command you will see what locales will be fetched before setting them:

```JAVA
ls.fetchAvailableLocales(stringId);
```

the return value is a **HashSet<Locale>** of the detected locales.

• • It may fail because even if you have a folder named values-ar it doesn't mean you have any resources there. If you have values-ar and you provide the LanguageSwitcher with a string that is not listed, or has the same characters in the same order then your locale will not be detected (i.e nice in US and nice in the UK).

Using this tab the user will be able to change the application language

<LinearLayout
    android:id="@id/language_layout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <TextView
        android:id="@id/languageText"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Language"
        android:textSize="13sp" />

    <TextView
        android:id="@id/current_language"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="11sp"
        tools:text="English" />
</LinearLayout>

LinearLayout languageView = (LinearLayout) layout.findViewById(R.id.language_layout);
languageView.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
    	// If you have a static declared switcher You can call it using the
    	// following line:
    	// MainApplication.languageSwitcher.showChangeLanguageDialog(this);
        new LanguageSwitcher(getActivity()).showChangeLanguageDialog();
    }
});

// The following 3 lines are extra and not needed :)
TextView language_tv = (TextView) layout.findViewById(R.id.current_language);
Locale currentLocale = getResources().getConfiguration().locale;
language_tv.setText(currentLocale.getDisplayName(currentLocale));

Yes! You did it. Your application now supports all Android supported locales.

1. To get a HashSet of the supported locales: ls.getLocales()
2. To set the supported locales using a HashSet<String> instead of HashSet<Locale>: ls.setSupportedStringLocales(supportedLocales)
3. To return to your launch locale (helpful when you have non-localized views): ls.switchToLaunch(SomeActivity.this)
4. To use your own DialogFragment with your custom design:
   1. Extend LanguagesListDialogFragment and override onCreateDialog. For example:

   public class ChangeLanguageDialogFragment extends LanguagesListDialogFragment	{
   	.
   	.
   	.
       @Override
       public Dialog onCreateDialog(Bundle savedInstanceState) {
           final AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
           .
           .
           .
           return builder.create();
       }
   
   	.
   	.
   	.
   }

   2. In positive button OnClickListener call: onPositiveClick();
   3. In OnItemClickListener use onLanguageSelected(position); or if you want to localize the dialog title, positive button, and negative button texts, call onLanguageSelectedLocalized(position, titleTextView, positiveBtn, negativeBtn);
   4. You can use other methods available in the parent class, such as:
      1. getLanguages() to get a display-ready languages.
      2. getCurrentLocaleIndex() to get the index of the locale that your app is displaying right now.

Rosetta is the first name of Rosetta Stone. Rosetta Stone is a granodiorite stele inscribed with a decree issued at Memphis, Egypt, in 196 BC on behalf of King Ptolemy V. The decree appears in three scripts: The upper text is Ancient Egyptian hieroglyphs, the middle portion is a Demotic script, and the lowest is Ancient Greek. The stone provided the key to the modern understanding of Egyptian hieroglyphs because it presented the same text in all three scripts (with some minor differences among them). Continue reading here.

The MIT License (MIT) Copyright (c) 2016 Ahmed Jazzar [email protected]

NOTE: This library does not translate your application localized strings, it's just helping you switch between them.