apps/SystemUtil/src/com/android/afwtest/systemutil/ChangeLocale.java

/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.afwtest.systemutil;

import android.app.Activity;
import android.app.Instrumentation;
import android.content.res.Configuration;
import android.os.Bundle;
import android.util.Log;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.Locale;

/**
 * Change the system locale.
 **/
public class ChangeLocale extends Instrumentation {
    private static final String TAG = "afwtest.ChangeLocale";

    // Locale code, expecting something like: en, en_US, en_UK, zh, zh_CN, zh_TW.
    private String mLocale;

    /**
     * {@inheritDoc}
     */
    @Override
    public void onCreate(Bundle arguments) {
        super.onCreate(arguments);
        mLocale = arguments.getString("locale", "");
        start();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void onStart() {
        super.onStart();

        // Locale must be specified.
        if (mLocale.isEmpty()) {
            handleError("Locale is not specified");
            return;
        }

        Log.i(TAG, String.format("Attempting to change locale to %s", mLocale));

        try {
            // It could be en_US or en.
            final String[] codes = mLocale.split("_");
            final Locale locale =
                    codes.length > 1 ? new Locale(codes[0], codes[1]) : new Locale(codes[0]);

            // Change locale through reflection.
            Class amnClass = Class.forName("android.app.ActivityManagerNative");
            Method getDefault = amnClass.getMethod("getDefault");
            getDefault.setAccessible(true);
            Object amn = getDefault.invoke(amnClass);

            Method getConfig = amnClass.getMethod("getConfiguration");
            getConfig.setAccessible(true);
            Configuration config = (Configuration) getConfig.invoke(amn);

            Field field = config.getClass().getField("userSetLocale");
            field.setBoolean(config, true);

            // Set new locale.
            config.locale = locale;

            // Update configuration.
            Method updateConfig = amnClass.getMethod("updateConfiguration", Configuration.class);
            updateConfig.setAccessible(true);
            updateConfig.invoke(amn, config);

            // Success
            Bundle results = new Bundle();
            results.putString("result", "SUCCESS");
            finish(Activity.RESULT_OK, results);
        } catch (Exception e) {
            Log.e(TAG, "Failed to change locale", e);
            handleError(String.format("Failed to change locale: %s", e));
        }
    }

    /**
     * Handles error by exiting instrumentation.
     *
     * @param errorMsg error msg
     */
    private void handleError(String errorMsg) {
        Bundle results = new Bundle();
        results.putString("error", errorMsg);
        finish(Activity.RESULT_CANCELED, results);
    }

}