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 android.util; 18 19 import java.util.Locale; 20 21 import android.view.View; 22 import libcore.icu.ICU; 23 24 /** 25 * Various utilities for Locales 26 * 27 * @hide 28 */ 29 public class LocaleUtil { 30 LocaleUtil()31 private LocaleUtil() { /* cannot be instantiated */ } 32 33 private static String ARAB_SCRIPT_SUBTAG = "Arab"; 34 private static String HEBR_SCRIPT_SUBTAG = "Hebr"; 35 36 /** 37 * Return the layout direction for a given Locale 38 * 39 * @param locale the Locale for which we want the layout direction. Can be null. 40 * @return the layout direction. This may be one of: 41 * {@link View#LAYOUT_DIRECTION_LTR} or 42 * {@link View#LAYOUT_DIRECTION_RTL}. 43 * 44 * Warning: this code does not support vertical scripts. 45 * @hide 46 */ getLayoutDirectionFromLocale(Locale locale)47 public static int getLayoutDirectionFromLocale(Locale locale) { 48 if (locale != null && !locale.equals(Locale.ROOT)) { 49 final String scriptSubtag = ICU.getScript(ICU.addLikelySubtags(locale.toString())); 50 if (scriptSubtag == null) return getLayoutDirectionFromFirstChar(locale); 51 52 if (scriptSubtag.equalsIgnoreCase(ARAB_SCRIPT_SUBTAG) || 53 scriptSubtag.equalsIgnoreCase(HEBR_SCRIPT_SUBTAG)) { 54 return View.LAYOUT_DIRECTION_RTL; 55 } 56 } 57 58 return View.LAYOUT_DIRECTION_LTR; 59 } 60 61 /** 62 * Fallback algorithm to detect the locale direction. Rely on the fist char of the 63 * localized locale name. This will not work if the localized locale name is in English 64 * (this is the case for ICU 4.4 and "Urdu" script) 65 * 66 * @param locale 67 * @return the layout direction. This may be one of: 68 * {@link View#LAYOUT_DIRECTION_LTR} or 69 * {@link View#LAYOUT_DIRECTION_RTL}. 70 * 71 * Warning: this code does not support vertical scripts. 72 * @hide 73 */ getLayoutDirectionFromFirstChar(Locale locale)74 private static int getLayoutDirectionFromFirstChar(Locale locale) { 75 switch(Character.getDirectionality(locale.getDisplayName(locale).charAt(0))) { 76 case Character.DIRECTIONALITY_RIGHT_TO_LEFT: 77 case Character.DIRECTIONALITY_RIGHT_TO_LEFT_ARABIC: 78 return View.LAYOUT_DIRECTION_RTL; 79 80 case Character.DIRECTIONALITY_LEFT_TO_RIGHT: 81 default: 82 return View.LAYOUT_DIRECTION_LTR; 83 } 84 } 85 } 86