Sample Android Application
Localization

Non-Native English Speaker's Localization Strategy

• Build an internationalized application in English first.
• Localize this application to support your native language next; Japanese in my case.
• You can support any other language in the same way. For example localization for Korean is easy if you can find a Korean-speaking person who can cooporate the work.

By first supporting English, the application can cover a considerable part of the world. Becuase there is a lot of people who understand English although their native language is different from it. This adds to the people in English language areas. After that, it is easy to support any other language than English and your native tongue if you have a need and resource.

In the rest of this page, I will show you how to localize an Android application. That work was painless because the I18N mechanism provided by Android OS matches very well with the non-native english speaker's strategy.

[res/values/strings.xml]

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="app_name">Internationalization and Localization</string>
    <string name="hello">Hello World.</string>
    <string name="byebye">Bye bye World</string>
    <string name="button">Change Text</string>
</resources>

The next is the Japanese resource file.

[res/values-ja/strings.xml]

As you can see, specifying a key such as "hello" or "byebye" will give you a greeting string suitable for English or Japanese.

This decision is made automatically by Android side. The mechanism is simple. If the current language setting is xx, strings.xml in values-xx will be referenced. It is values-ja for Japanese and values-en for English. If no values-xx is prepared for some xx, strings.xml in just values without xx will be referenced. In other words, for a language with values-xx, strings.xml in that folder will be referenced. For other languages without values-xx, strings.xml in the default values will be referenced.

In order to take the non-english speaker's strategy, English should be the default language while the Japanese, my mother tongue, is the first localized language. The English strings will be stored in values/strings.xml and the Japanese strings are stored in values-ja/strings.xml. The values-ja/strings.xml is used only if the language is set to Japanese. Otherwise, default values/strings.xml is used. The English strings will be displayed if the user's language is set to English (en), Korean (ko) or German (de), to name a few.

[src/sample.i18n/I18N.java]

public class I18N extends Activity ... {

    ...

    public void onClick(View v) {
        if (v.getId() == R.id.button1) {
            String greeing = getString(R.string.byebye);
            textView.setText(greeting);
        }
    }
}

The getString is a method defined in the Context class (android.content.Context) which is one of the superclasses of the Activity class (android.app.Activity). You can call this one-shot method to get a localized string.

You may wonder what is "R.string" here.
This is an ID automatically generated by the Android plugin when you add a string to a resource file. It resides in R.java in gen folder under the application folder.

[gen/sample.i18n/R.java]

/* AUTO-GENERATED FILE.  DO NOT MODIFY.
 *
 * This class was automatically generated by the
 * aapt tool from the resource data it found.  It
 * should not be modified by hand.
 */

package sample.i18n;

public final class R {
    public static final class attr {
    }
    public static final class drawable {
        public static final int icon=0x7f020000;
    }
    public static final class id {
        public static final int button1=0x7f050001;
        public static final int textView1=0x7f050000;
    }
    public static final class layout {
        public static final int main=0x7f030000;
    }
    public static final class string {
        public static final int app_name=0x7f040000;
        public static final int button=0x7f040003;
        public static final int byebye=0x7f040002;
        public static final int hello=0x7f040001;
    }
}

As you can see, you can reference an ID of a graphics file such as an icon, layout definition and UI component as well as a string.

[res/layout/main.xml]

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <TextView android:layout_weight="0.9" android:id="@+id/textView1"
        android:text="@string/hello" android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center" android:isScrollContainer="true"
        android:background="#AAAAAA" android:textColor="#333333">
    </TextView>
    <Button android:layout_width="match_parent"
        android:layout_height="wrap_content" android:id="@+id/button1"
        android:layout_weight="0.1" android:text="@string/button"
        android:gravity="center">
    </Button>
</LinearLayout>

The syntax for referencing a string resource within a layout XML file is "@string/<id>". You can see that the TextView in the middle of the screen is given "hello" resulting the string of "Hello World" if in English. The Button at the bottom is given "button" so its name will be "Change Text" in English.

[AndroidManifest.xml]

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android= ...

    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".I18N"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

[src/sample.i18n/I18N.java]

package sample.i18n;

import java.util.Locale;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

// Sample application for demonstrating non-English-speaker's
// localization strategy.
// 2011 Apr 17 Written for test by ARAI, Bunkichi, Kobu.Com,
// 2011 Jul 24 Updated for demonstration

public class I18N extends Activity implements OnClickListener {
    
    private String logtag = getClass().getSimpleName();
    
    private TextView textView;
    
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    
        textView = (TextView) findViewById(R.id.textView1);
        
        Button button = (Button) findViewById(R.id.button1);
        button.setOnClickListener(this);
        
        Locale locale = Locale.getDefault(); // current locale
         Locale locale = getResources().getConfiguration().locale;  or you can ...
        Log.d(logtag, "lang = " + locale.getLanguage());
    }

    @Override
    public void onClick(View v) {
        if (v.getId() == R.id.button1) {
            textView.setText(getString(R.string.byebye)); // set localized text
             textView.setText(R.string.byebye);  or you can do it faster
        }
    }
}

This is the end of introduction to a simple localization of an Android application.

All the external resource files listed above and the source code are included in the Eclipse project you can download.

Download: Eclipse Android Application Project - I18N.zip