Merge "[Panlingual] Revamp the panlingual UI in Settings." into tm-dev

src/com/android/settings/Settings.java

@@ -111,8 +111,6 @@ public class Settings extends SettingsActivity {
     public static class InputMethodAndSubtypeEnablerActivity extends SettingsActivity { /* empty */ }
     public static class SpellCheckersSettingsActivity extends SettingsActivity { /* empty */ }
     public static class LocalePickerActivity extends SettingsActivity { /* empty */ }
-    /** Activity for the App locale details settings. */
-    public static class AppLocalePickerActivity extends SettingsActivity { /* empty */ }
     public static class LanguageAndInputSettingsActivity extends SettingsActivity { /* empty */ }
     public static class UserDictionarySettingsActivity extends SettingsActivity { /* empty */ }
     public static class DarkThemeSettingsActivity extends SettingsActivity { /* empty */ }

src/com/android/settings/applications/appinfo/AppLocaleDetails.java

@@ -22,73 +22,64 @@ import android.app.LocaleConfig;
 import android.app.LocaleManager;
 import android.app.settings.SettingsEnums;
 import android.content.Context;
+import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageManager;
-import android.content.res.Resources;
 import android.os.Bundle;
 import android.os.LocaleList;
-import android.telephony.TelephonyManager;
 import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.TextView;
 
-import androidx.annotation.VisibleForTesting;
-import androidx.appcompat.app.AlertDialog;
 import androidx.preference.Preference;
-import androidx.preference.PreferenceGroup;
 
 import com.android.settings.R;
+import com.android.settings.SettingsPreferenceFragment;
 import com.android.settings.Utils;
 import com.android.settings.applications.AppInfoBase;
 import com.android.settings.widget.EntityHeaderController;
 import com.android.settingslib.applications.AppUtils;
 import com.android.settingslib.widget.LayoutPreference;
-import com.android.settingslib.widget.RadioButtonPreference;
 
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.HashSet;
 import java.util.Locale;
 
 /**
- * A fragment to show the current app locale info and help the user to select the expected locale.
+ * TODO(b/223503670): Implement the unittest.
+ * A fragment to show the current app locale info.
  */
-public class AppLocaleDetails extends AppInfoBase implements RadioButtonPreference.OnClickListener {
+public class AppLocaleDetails extends SettingsPreferenceFragment {
     private static final String TAG = "AppLocaleDetails";
 
-    private static final String CATEGORY_KEY_SUGGESTED_LANGUAGES =
-            "category_key_suggested_languages";
-    private static final String CATEGORY_KEY_ALL_LANGUAGES =
-            "category_key_all_languages";
     private static final String KEY_APP_DESCRIPTION = "app_locale_description";
-    @VisibleForTesting
-    static final String KEY_SYSTEM_DEFAULT_LOCALE = "system_default_locale";
 
     private boolean mCreated = false;
-    @VisibleForTesting
-    AppLocaleDetailsHelper mAppLocaleDetailsHelper;
-
-    private PreferenceGroup mGroupOfSuggestedLocales;
-    private PreferenceGroup mGroupOfSupportedLocales;
+    private String mPackageName;
     private LayoutPreference mPrefOfDescription;
-    private RadioButtonPreference mDefaultPreference;
+
+    /**
+     * Create a instance of AppLocaleDetails.
+     * @param packageName Indicates which application need to show the locale picker.
+     */
+    public static AppLocaleDetails newInstance(String packageName) {
+        AppLocaleDetails appLocaleDetails = new AppLocaleDetails();
+        Bundle bundle = new Bundle();
+        bundle.putString(AppInfoBase.ARG_PACKAGE_NAME, packageName);
+        appLocaleDetails.setArguments(bundle);
+        return appLocaleDetails;
+    }
 
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         addPreferencesFromResource(R.xml.app_locale_details);
-        mAppLocaleDetailsHelper = new AppLocaleDetailsHelper(getContext(), mPackageName);
+        Bundle bundle = getArguments();
+        mPackageName = bundle.getString(AppInfoBase.ARG_PACKAGE_NAME, "");
 
-        mGroupOfSuggestedLocales =
-                getPreferenceScreen().findPreference(CATEGORY_KEY_SUGGESTED_LANGUAGES);
-        mGroupOfSupportedLocales =
-                getPreferenceScreen().findPreference(CATEGORY_KEY_ALL_LANGUAGES);
-        mPrefOfDescription = getPreferenceScreen().findPreference(KEY_APP_DESCRIPTION);
-
-        mDefaultPreference = (RadioButtonPreference) getPreferenceScreen()
-                .findPreference(KEY_SYSTEM_DEFAULT_LOCALE);
-        mDefaultPreference.setOnClickListener(this);
+        if (mPackageName.isEmpty()) {
+            Log.d(TAG, "No package name.");
+            finish();
+        }
     }
 
     // Override here so we don't have an empty screen
@@ -96,8 +87,8 @@ public class AppLocaleDetails extends AppInfoBase implements RadioButtonPreferen
     public View onCreateView(LayoutInflater inflater,
             ViewGroup container,
             Bundle savedInstanceState) {
-        // if we don't have a package info, show a page saying this is unsupported
-        if (mPackageInfo == null) {
+        // if we don't have a package, show a page saying this is unsupported
+        if (mPackageName.isEmpty()) {
             return inflater.inflate(R.layout.manage_applications_apps_unsupported, null);
         }
         return super.onCreateView(inflater, container, savedInstanceState);
@@ -105,46 +96,19 @@ public class AppLocaleDetails extends AppInfoBase implements RadioButtonPreferen
 
     @Override
     public void onResume() {
-        // Update Locales first, before refresh ui.
-        mAppLocaleDetailsHelper.handleAllLocalesData();
-        super.onResume();
-        mDefaultPreference.setSummary(Locale.getDefault().getDisplayName(Locale.getDefault()));
-    }
-
-    @Override
-    protected boolean refreshUi() {
         refreshUiInternal();
-        return true;
+        super.onResume();
     }
 
-    @VisibleForTesting
-    void refreshUiInternal() {
-        if (mAppLocaleDetailsHelper.getSupportedLocales().isEmpty()) {
+    private void refreshUiInternal() {
+        if (!hasAppSupportedLocales()) {
             Log.d(TAG, "No supported language.");
-            mGroupOfSuggestedLocales.setVisible(false);
-            mGroupOfSupportedLocales.setVisible(false);
             mPrefOfDescription.setVisible(true);
             TextView description = (TextView) mPrefOfDescription.findViewById(R.id.description);
             description.setText(getContext().getString(R.string.no_multiple_language_supported,
                     Locale.getDefault().getDisplayName(Locale.getDefault())));
             return;
         }
-        resetLocalePreferences();
-        Locale appLocale = AppLocaleDetailsHelper.getAppDefaultLocale(getContext(), mPackageName);
-        // Sets up default locale preference.
-        mGroupOfSuggestedLocales.addPreference(mDefaultPreference);
-        mDefaultPreference.setChecked(appLocale == null);
-        // Sets up suggested locales of per app.
-        setLanguagesPreference(mGroupOfSuggestedLocales,
-                mAppLocaleDetailsHelper.getSuggestedLocales(), appLocale);
-        // Sets up supported locales of per app.
-        setLanguagesPreference(mGroupOfSupportedLocales,
-                mAppLocaleDetailsHelper.getSupportedLocales(), appLocale);
-    }
-
-    private void resetLocalePreferences() {
-        mGroupOfSuggestedLocales.removeAll();
-        mGroupOfSupportedLocales.removeAll();
     }
 
     @Override
@@ -152,22 +116,6 @@ public class AppLocaleDetails extends AppInfoBase implements RadioButtonPreferen
         return SettingsEnums.APPS_LOCALE_LIST;
     }
 
-    @Override
-    protected AlertDialog createDialog(int id, int errorCode) {
-        return null;
-    }
-
-    @Override
-    public void onRadioButtonClicked(RadioButtonPreference pref) {
-        String key = pref.getKey();
-        if (KEY_SYSTEM_DEFAULT_LOCALE.equals(key)) {
-            mAppLocaleDetailsHelper.setAppDefaultLocale(LocaleList.forLanguageTags(""));
-        } else {
-            mAppLocaleDetailsHelper.setAppDefaultLocale(key);
-        }
-        refreshUi();
-    }
-
     @Override
     public void onActivityCreated(Bundle savedInstanceState) {
         super.onActivityCreated(savedInstanceState);
@@ -176,32 +124,98 @@ public class AppLocaleDetails extends AppInfoBase implements RadioButtonPreferen
             return;
         }
         mCreated = true;
-        if (mPackageInfo == null) {
+        if (mPackageName == null) {
             return;
         }
         // Creates a head icon button of app on this page.
         final Activity activity = getActivity();
+        ApplicationInfo applicationInfo =
+                getApplicationInfo(mPackageName, getContext().getUserId());
         final Preference pref = EntityHeaderController
                 .newInstance(activity, this, null /* header */)
                 .setRecyclerView(getListView(), getSettingsLifecycle())
-                .setIcon(Utils.getBadgedIcon(getContext(), mPackageInfo.applicationInfo))
-                .setLabel(mPackageInfo.applicationInfo.loadLabel(mPm))
-                .setIsInstantApp(AppUtils.isInstant(mPackageInfo.applicationInfo))
+                .setIcon(Utils.getBadgedIcon(getContext(), applicationInfo))
+                .setLabel(applicationInfo.loadLabel(getContext().getPackageManager()))
+                .setIsInstantApp(AppUtils.isInstant(applicationInfo))
                 .setPackageName(mPackageName)
-                .setUid(mPackageInfo.applicationInfo.uid)
+                .setUid(applicationInfo.uid)
                 .setHasAppInfoLink(true)
                 .setButtonActions(ActionType.ACTION_NONE, ActionType.ACTION_NONE)
                 .done(activity, getPrefContext());
         getPreferenceScreen().addPreference(pref);
     }
 
+    private ApplicationInfo getApplicationInfo(String packageName, int userId) {
+        ApplicationInfo applicationInfo;
+        try {
+            applicationInfo = getContext().getPackageManager()
+                    .getApplicationInfoAsUser(packageName, /* flags= */ 0, userId);
+            return applicationInfo;
+        } catch (PackageManager.NameNotFoundException e) {
+            Log.w(TAG, "Application info not found for: " + packageName);
+            return null;
+        }
+    }
+
+    private boolean hasAppSupportedLocales() {
+        LocaleList localeList = getPackageLocales();
+        return (localeList != null && localeList.size() > 0) || getAssetLocales().length > 0;
+    }
+
+    private String[] getAssetLocales() {
+        try {
+            PackageManager packageManager = getContext().getPackageManager();
+            String[] locales = packageManager.getResourcesForApplication(
+                    packageManager.getPackageInfo(mPackageName, PackageManager.MATCH_ALL)
+                            .applicationInfo).getAssets().getNonSystemLocales();
+            if (locales == null) {
+                Log.i(TAG, "[" + mPackageName + "] locales are null.");
+            }
+            if (locales.length <= 0) {
+                Log.i(TAG, "[" + mPackageName + "] locales length is 0.");
+                return new String[0];
+            }
+            String locale = locales[0];
+            Log.i(TAG, "First asset locale - [" + mPackageName + "] " + locale);
+            return locales;
+        } catch (PackageManager.NameNotFoundException e) {
+            Log.w(TAG, "Can not found the package name : " + mPackageName + " / " + e);
+        }
+        return new String[0];
+    }
+
+    private LocaleList getPackageLocales() {
+        try {
+            LocaleConfig localeConfig =
+                    new LocaleConfig(getContext().createPackageContext(mPackageName, 0));
+            if (localeConfig.getStatus() == LocaleConfig.STATUS_SUCCESS) {
+                return localeConfig.getSupportedLocales();
+            }
+        } catch (PackageManager.NameNotFoundException e) {
+            Log.w(TAG, "Can not found the package name : " + mPackageName + " / " + e);
+        }
+        return null;
+    }
+
+    /** Gets per app's default locale */
+    public static Locale getAppDefaultLocale(Context context, String packageName) {
+        LocaleManager localeManager = context.getSystemService(LocaleManager.class);
+        try {
+            LocaleList localeList = (localeManager == null)
+                    ? null : localeManager.getApplicationLocales(packageName);
+            return localeList == null ? null : localeList.get(0);
+        } catch (IllegalArgumentException e) {
+            Log.w(TAG, "package name : " + packageName + " is not correct. " + e);
+        }
+        return null;
+    }
+
     /**
      * TODO (b209962418) Do a performance test to low end device.
      * @return Return the summary to show the current app's language.
      */
     public static CharSequence getSummary(Context context, String packageName) {
-        Locale appLocale =
-                AppLocaleDetailsHelper.getAppDefaultLocale(context, packageName);
+        Locale appLocale = getAppDefaultLocale(context, packageName);
         if (appLocale == null) {
             Locale systemLocale = Locale.getDefault();
             return context.getString(R.string.preference_of_system_locale_summary,
@@ -210,217 +224,4 @@ public class AppLocaleDetails extends AppInfoBase implements RadioButtonPreferen
             return appLocale.getDisplayName(appLocale);
         }
     }
-
-    private void setLanguagesPreference(PreferenceGroup group,
-            Collection<Locale> locales, Locale appLocale) {
-        if (locales == null) {
-            return;
-        }
-
-        for (Locale locale : locales) {
-            if (locale == null) {
-                continue;
-            }
-
-            RadioButtonPreference pref = new RadioButtonPreference(getContext());
-            pref.setTitle(locale.getDisplayName(locale));
-            pref.setKey(locale.toLanguageTag());
-            // Will never be checked if appLocale is null
-            // aka if there is no per-app locale
-            pref.setChecked(locale.equals(appLocale));
-            pref.setOnClickListener(this);
-            group.addPreference(pref);
-        }
-    }
-
-    @VisibleForTesting
-    static class AppLocaleDetailsHelper {
-        private String mPackageName;
-        private Context mContext;
-        private TelephonyManager mTelephonyManager;
-        private LocaleManager mLocaleManager;
-
-        private Collection<Locale> mProcessedSuggestedLocales = new ArrayList<>();
-        private Collection<Locale> mProcessedSupportedLocales = new ArrayList<>();
-
-        private Collection<Locale> mAppSupportedLocales = new ArrayList<>();
-
-        AppLocaleDetailsHelper(Context context, String packageName) {
-            mContext = context;
-            mPackageName = packageName;
-            mTelephonyManager = context.getSystemService(TelephonyManager.class);
-            mLocaleManager = context.getSystemService(LocaleManager.class);
-            mAppSupportedLocales = getAppSupportedLocales();
-        }
-
-        /** Handle suggested and supported locales for UI display. */
-        public void handleAllLocalesData() {
-            clearLocalesData();
-            handleSuggestedLocales();
-            handleSupportedLocales();
-        }
-
-        /** Gets suggested locales in the app. */
-        public Collection<Locale> getSuggestedLocales() {
-            return mProcessedSuggestedLocales;
-        }
-
-        /** Gets supported locales in the app. */
-        public Collection<Locale> getSupportedLocales() {
-            return mProcessedSupportedLocales;
-        }
-
-        @VisibleForTesting
-        void handleSuggestedLocales() {
-            Locale appLocale = getAppDefaultLocale(mContext, mPackageName);
-            // 1st locale in suggested languages group.
-            for (Locale supportedlocale : mAppSupportedLocales) {
-                if (compareLocale(supportedlocale, appLocale)) {
-                    mProcessedSuggestedLocales.add(appLocale);
-                    break;
-                }
-            }
-
-            // 2nd and 3rd locale in suggested languages group.
-            String simCountry = mTelephonyManager.getSimCountryIso().toUpperCase(Locale.US);
-            String networkCountry = mTelephonyManager.getNetworkCountryIso().toUpperCase(Locale.US);
-            mAppSupportedLocales.forEach(supportedlocale -> {
-                String localeCountry = supportedlocale.getCountry().toUpperCase(Locale.US);
-                if (!compareLocale(supportedlocale, appLocale)
-                        && isCountrySuggestedLocale(localeCountry, simCountry, networkCountry)) {
-                    mProcessedSuggestedLocales.add(supportedlocale);
-                }
-            });
-
-            // Other locales in suggested languages group.
-            Collection<Locale> supportedSystemLocales = new HashSet<>();
-            getCurrentSystemLocales().forEach(systemLocale -> {
-                mAppSupportedLocales.forEach(supportedLocale -> {
-                    if (compareLocale(systemLocale, supportedLocale)) {
-                        supportedSystemLocales.add(supportedLocale);
-                    }
-                });
-            });
-            supportedSystemLocales.removeAll(mProcessedSuggestedLocales);
-            mProcessedSuggestedLocales.addAll(supportedSystemLocales);
-        }
-
-        @VisibleForTesting
-        static boolean compareLocale(Locale source, Locale target) {
-            if (source == null && target == null) {
-                return true;
-            } else if (source != null && target != null) {
-                return LocaleList.matchesLanguageAndScript(source, target);
-            } else {
-                return false;
-            }
-        }
-
-        private static boolean isCountrySuggestedLocale(String localeCountry,
-                String simCountry,
-                String networkCountry) {
-            return ((!simCountry.isEmpty() && simCountry.equals(localeCountry))
-                    || (!networkCountry.isEmpty() && networkCountry.equals(localeCountry)));
-        }
-
-        @VisibleForTesting
-        void handleSupportedLocales() {
-            mProcessedSupportedLocales.addAll(mAppSupportedLocales);
-
-            if (mProcessedSuggestedLocales != null || !mProcessedSuggestedLocales.isEmpty()) {
-                mProcessedSuggestedLocales.retainAll(mProcessedSupportedLocales);
-                mProcessedSupportedLocales.removeAll(mProcessedSuggestedLocales);
-            }
-        }
-
-        private void clearLocalesData() {
-            mProcessedSuggestedLocales.clear();
-            mProcessedSupportedLocales.clear();
-        }
-
-        private Collection<Locale> getAppSupportedLocales() {
-            Collection<Locale> appSupportedLocales = new ArrayList<>();
-            LocaleList localeList = getPackageLocales();
-
-            if (localeList != null && localeList.size() > 0) {
-                for (int i = 0; i < localeList.size(); i++) {
-                    appSupportedLocales.add(localeList.get(i));
-                }
-            } else {
-                String[] languages = getAssetLocales();
-                for (String language : languages) {
-                    appSupportedLocales.add(Locale.forLanguageTag(language));
-                }
-            }
-            return appSupportedLocales;
-        }
-
-        /** Gets per app's default locale */
-        public static Locale getAppDefaultLocale(Context context, String packageName) {
-            LocaleManager localeManager = context.getSystemService(LocaleManager.class);
-            try {
-                LocaleList localeList = (localeManager == null)
-                        ? null : localeManager.getApplicationLocales(packageName);
-                return localeList == null ? null : localeList.get(0);
-            } catch (IllegalArgumentException e) {
-                Log.w(TAG, "package name : " + packageName + " is not correct. " + e);
-            }
-            return null;
-        }
-
-        /** Sets per app's default language to system. */
-        public void setAppDefaultLocale(String languageTag) {
-            if (languageTag.isEmpty()) {
-                Log.w(TAG, "[setAppDefaultLocale] No language tag.");
-                return;
-            }
-            setAppDefaultLocale(LocaleList.forLanguageTags(languageTag));
-        }
-
-        /** Sets per app's default language to system. */
-        public void setAppDefaultLocale(LocaleList localeList) {
-            if (mLocaleManager == null) {
-                Log.w(TAG, "LocaleManager is null, and cannot set the app locale up.");
-                return;
-            }
-            mLocaleManager.setApplicationLocales(mPackageName, localeList);
-        }
-
-        @VisibleForTesting
-        Collection<Locale> getCurrentSystemLocales() {
-            LocaleList localeList = Resources.getSystem().getConfiguration().getLocales();
-            Collection<Locale> systemLocales = new ArrayList<>();
-            for (int i = 0; i < localeList.size(); i++) {
-                systemLocales.add(localeList.get(i));
-            }
-            return systemLocales;
-        }
-
-        @VisibleForTesting
-        String[] getAssetLocales() {
-            try {
-                PackageManager packageManager = mContext.getPackageManager();
-                return packageManager.getResourcesForApplication(
-                        packageManager.getPackageInfo(mPackageName, PackageManager.MATCH_ALL)
-                                .applicationInfo).getAssets().getNonSystemLocales();
-            } catch (PackageManager.NameNotFoundException e) {
-                Log.w(TAG, "Can not found the package name : " + mPackageName + " / " + e);
-            }
-            return new String[0];
-        }
-
-        @VisibleForTesting
-        LocaleList getPackageLocales() {
-            try {
-                LocaleConfig localeConfig =
-                        new LocaleConfig(mContext.createPackageContext(mPackageName, 0));
-                if (localeConfig.getStatus() == LocaleConfig.STATUS_SUCCESS) {
-                    return localeConfig.getSupportedLocales();
-                }
-            } catch (PackageManager.NameNotFoundException e) {
-                Log.w(TAG, "Can not found the package name : " + mPackageName + " / " + e);
-            }
-            return null;
-        }
-    }
 }

src/com/android/settings/applications/manageapplications/ManageApplications.java

@@ -120,6 +120,7 @@ import com.android.settings.core.InstrumentedFragment;
 import com.android.settings.core.SubSettingLauncher;
 import com.android.settings.dashboard.profileselector.ProfileSelectFragment;
 import com.android.settings.fuelgauge.HighPowerDetail;
+import com.android.settings.localepicker.AppLocalePickerActivity;
 import com.android.settings.notification.ConfigureNotificationSettings;
 import com.android.settings.notification.NotificationBackend;
 import com.android.settings.notification.app.AppNotificationSettings;
@@ -635,8 +636,9 @@ public class ManageApplications extends InstrumentedFragment
                         R.string.media_management_apps_title);
                 break;
             case LIST_TYPE_APPS_LOCALE:
-                startAppInfoFragment(AppLocaleDetails.class,
-                        R.string.app_locale_picker_title);
+                Intent intent = new Intent(getContext(), AppLocalePickerActivity.class);
+                intent.setData(Uri.parse("package:" + mCurrentPkgName));
+                startActivity(intent);
                 break;
             // TODO: Figure out if there is a way where we can spin up the profile's settings
             // process ahead of time, to avoid a long load of data when user clicks on a managed

src/com/android/settings/localepicker/AppLocalePickerActivity.java

@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) 2022 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.settings.localepicker;
+
+import android.app.FragmentTransaction;
+import android.os.Bundle;
+import android.text.TextUtils;
+import android.util.Log;
+import android.view.MenuItem;
+
+import com.android.internal.app.LocalePickerWithRegion;
+import com.android.internal.app.LocaleStore;
+import com.android.settings.R;
+import com.android.settings.applications.appinfo.AppLocaleDetails;
+import com.android.settings.core.SettingsBaseActivity;
+
+/**
+ * TODO(b/223503670): Add unit test for AppLocalePickerActivity.
+ * A activity to show the locale picker and information page.
+ */
+public class AppLocalePickerActivity extends SettingsBaseActivity
+        implements LocalePickerWithRegion.LocaleSelectedListener {
+    private static final String TAG = AppLocalePickerActivity.class.getSimpleName();
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        String packageName = getIntent().getData().getSchemeSpecificPart();
+        if (TextUtils.isEmpty(packageName)) {
+            Log.d(TAG, "There is no package name.");
+            finish();
+            return;
+        }
+
+        getActionBar().setDisplayHomeAsUpEnabled(true);
+        setContentView(R.layout.app_locale_picker);
+
+        // Create App locale info detail part.
+        AppLocaleDetails appLocaleDetails = AppLocaleDetails.newInstance(packageName);
+        getSupportFragmentManager()
+                .beginTransaction()
+                .replace(R.id.app_locale_detail, appLocaleDetails)
+                .commit();
+
+        // Create Locale picker part.
+        final LocalePickerWithRegion selector = LocalePickerWithRegion.createLanguagePicker(
+                this, AppLocalePickerActivity.this, false /* translate only */);
+        // LocalePickerWithRegion use android.app.ListFragment. Thus, it can not user
+        // getSupportFragmentManager() to add this into container.
+        getFragmentManager()
+                .beginTransaction()
+                .setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN)
+                .replace(R.id.app_locale_picker_with_region, selector)
+                .commit();
+    }
+
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item) {
+        if (item.getItemId() == android.R.id.home) {
+            handleBackPressed();
+            return true;
+        }
+        return super.onOptionsItemSelected(item);
+    }
+
+    @Override
+    public void onBackPressed() {
+        handleBackPressed();
+    }
+
+    private void handleBackPressed() {
+        if (getFragmentManager().getBackStackEntryCount() > 1) {
+            super.onBackPressed();
+        } else {
+            setResult(RESULT_CANCELED);
+            finish();
+        }
+    }
+
+    @Override
+    public void onLocaleSelected(LocaleStore.LocaleInfo locale) {
+        // TODO When locale is selected, this shall set per app language here.
+        finish();
+    }
+}
+

src/com/android/settings/localepicker/LocalePickerWithRegionActivity.java

@@ -17,8 +17,11 @@
 package com.android.settings.localepicker;
 
 import android.app.FragmentTransaction;
+import android.app.LocaleManager;
 import android.content.Intent;
 import android.os.Bundle;
+import android.os.LocaleList;
+import android.util.Log;
 import android.view.MenuItem;
 
 import com.android.internal.app.LocalePickerWithRegion;
@@ -31,6 +34,7 @@ public class LocalePickerWithRegionActivity extends SettingsBaseActivity
         implements LocalePickerWithRegion.LocaleSelectedListener {
 
     private static final String PARENT_FRAGMENT_NAME = "localeListEditor";
+    private static final String TAG = "Calvin";
 
     @Override
     public void onCreate(Bundle savedInstanceState) {
@@ -47,6 +51,25 @@ public class LocalePickerWithRegionActivity extends SettingsBaseActivity
                 .commit();
     }
 
+    public void setAppDefaultLocale(String languageTag) {
+        if (languageTag.isEmpty()) {
+            Log.w(TAG, "[setAppDefaultLocale] No language tag.");
+            return;
+        }
+        setAppDefaultLocale(LocaleList.forLanguageTags(languageTag));
+    }
+
+    /** Sets per app's default language to system. */
+    public void setAppDefaultLocale(LocaleList localeList) {
+        LocaleManager mLocaleManager = getSystemService(LocaleManager.class);
+        if (mLocaleManager == null) {
+            Log.w(TAG, "LocaleManager is null, and cannot set the app locale up.");
+            return;
+        }
+        mLocaleManager.setApplicationLocales("com.android.vending", localeList);
+    }
+
+
     @Override
     public boolean onOptionsItemSelected(MenuItem item) {
         if (item.getItemId() == android.R.id.home) {
@@ -58,9 +81,16 @@ public class LocalePickerWithRegionActivity extends SettingsBaseActivity
 
     @Override
     public void onLocaleSelected(LocaleStore.LocaleInfo locale) {
-        final Intent intent = new Intent();
+        /*final Intent intent = new Intent();
         intent.putExtra(LocaleListEditor.INTENT_LOCALE_KEY, locale);
-        setResult(RESULT_OK, intent);
+        setResult(RESULT_OK, intent);*/
+        if(locale != null) {
+            Log.d("Calvin", "onLocaleSelected " + locale.getLocale().toLanguageTag());
+            setAppDefaultLocale(locale.getLocale().toLanguageTag());
+        } else {
+            Log.d("Calvin", "onLocaleSelected null");
+            setAppDefaultLocale("");
+        }
         finish();
     }