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      1 /*
      2  * Copyright (C) 2011 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.contacts.util;
     18 
     19 import android.content.Context;
     20 import android.content.res.Configuration;
     21 import android.content.res.Resources;
     22 
     23 import java.util.Locale;
     24 
     25 /**
     26  * Utility class to save and restore the locale of the system.
     27  * <p>
     28  * This can be used for tests that assume to be run in a certain locale, e.g., because they
     29  * check against strings in a particular language or require an assumption on how the system
     30  * will behave in a specific locale.
     31  * <p>
     32  * In your test, you can change the locale with the following code:
     33  * <pre>
     34  * public class CanadaFrenchTest extends AndroidTestCase {
     35  *     private LocaleTestUtils mLocaleTestUtils;
     36  *
     37  *     &#64;Override
     38  *     public void setUp() throws Exception {
     39  *         super.setUp();
     40  *         mLocaleTestUtils = new LocaleTestUtils(getContext());
     41  *         mLocaleTestUtils.setLocale(Locale.CANADA_FRENCH);
     42  *     }
     43  *
     44  *     &#64;Override
     45  *     public void tearDown() throws Exception {
     46  *         mLocaleTestUtils.restoreLocale();
     47  *         mLocaleTestUtils = null;
     48  *         super.tearDown();
     49  *     }
     50  *
     51  *     ...
     52  * }
     53  * </pre>
     54  * Note that one should not call {@link #setLocale(Locale)} more than once without calling
     55  * {@link #restoreLocale()} first.
     56  * <p>
     57  * This class is not thread-safe. Usually its methods should be invoked only from the test thread.
     58  */
     59 public class LocaleTestUtils {
     60     private final Context mContext;
     61     private boolean mSaved;
     62     private Locale mSavedContextLocale;
     63     private Locale mSavedSystemLocale;
     64 
     65     /**
     66      * Create a new instance that can be used to set and reset the locale for the given context.
     67      *
     68      * @param context the context on which to alter the locale
     69      */
     70     public LocaleTestUtils(Context context) {
     71         mContext = context;
     72         mSaved = false;
     73     }
     74 
     75     /**
     76      * Set the locale to the given value and saves the previous value.
     77      *
     78      * @param locale the value to which the locale should be set
     79      * @throws IllegalStateException if the locale was already set
     80      */
     81     public void setLocale(Locale locale) {
     82         if (mSaved) {
     83             throw new IllegalStateException(
     84                     "call restoreLocale() before calling setLocale() again");
     85         }
     86         mSavedContextLocale = setResourcesLocale(mContext.getResources(), locale);
     87         mSavedSystemLocale = setResourcesLocale(Resources.getSystem(), locale);
     88         mSaved = true;
     89     }
     90 
     91     /**
     92      * Restores the previously set locale.
     93      *
     94      * @throws IllegalStateException if the locale was not set using {@link #setLocale(Locale)}
     95      */
     96     public void restoreLocale() {
     97         if (!mSaved) {
     98             throw new IllegalStateException("call setLocale() before calling restoreLocale()");
     99         }
    100         setResourcesLocale(mContext.getResources(), mSavedContextLocale);
    101         setResourcesLocale(Resources.getSystem(), mSavedSystemLocale);
    102         mSaved = false;
    103     }
    104 
    105     /**
    106      * Sets the locale for the given resources and returns the previous locale.
    107      *
    108      * @param resources the resources on which to set the locale
    109      * @param locale the value to which to set the locale
    110      * @return the previous value of the locale for the resources
    111      */
    112     private Locale setResourcesLocale(Resources resources, Locale locale) {
    113         Configuration contextConfiguration = new Configuration(resources.getConfiguration());
    114         Locale savedLocale = contextConfiguration.locale;
    115         contextConfiguration.locale = locale;
    116         resources.updateConfiguration(contextConfiguration, null);
    117         return savedLocale;
    118     }
    119 }