/*
* Copyright (C) 2015 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.settingslib.datetime;
import android.content.Context;
import android.content.res.XmlResourceParser;
import android.icu.text.TimeZoneNames;
import android.text.BidiFormatter;
import android.text.TextDirectionHeuristics;
import android.text.TextUtils;
import android.util.Log;
import android.view.View;
import com.android.settingslib.R;
import org.xmlpull.v1.XmlPullParserException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.TimeZone;
public class ZoneGetter {
private static final String TAG = "ZoneGetter";
private static final String XMLTAG_TIMEZONE = "timezone";
public static final String KEY_ID = "id"; // value: String
public static final String KEY_DISPLAYNAME = "name"; // value: String
public static final String KEY_GMT = "gmt"; // value: String
public static final String KEY_OFFSET = "offset"; // value: int (Integer)
private ZoneGetter() {}
public static String getTimeZoneOffsetAndName(TimeZone tz, Date now) {
Locale locale = Locale.getDefault();
String gmtString = getGmtOffsetString(locale, tz, now);
TimeZoneNames timeZoneNames = TimeZoneNames.getInstance(locale);
String zoneNameString = getZoneLongName(timeZoneNames, tz, now);
if (zoneNameString == null) {
return gmtString;
}
// We don't use punctuation here to avoid having to worry about localizing that too!
return gmtString + " " + zoneNameString;
}
public static List<Map<String, Object>> getZonesList(Context context) {
final Locale locale = Locale.getDefault();
final Date now = new Date();
final TimeZoneNames timeZoneNames = TimeZoneNames.getInstance(locale);
// The display name chosen for each zone entry depends on whether the zone is one associated
// with the country of the user's chosen locale. For "local" zones we prefer the "long name"
// (e.g. "Europe/London" -> "British Summer Time" for people in the UK). For "non-local"
// zones we prefer the exemplar location (e.g. "Europe/London" -> "London" for English
// speakers from outside the UK). This heuristic is based on the fact that people are
// typically familiar with their local timezones and exemplar locations don't always match
// modern-day expectations for people living in the country covered. Large countries like
// China that mostly use a single timezone (olson id: "Asia/Shanghai") may not live near
// "Shanghai" and prefer the long name over the exemplar location. The only time we don't
// follow this policy for local zones is when Android supplies multiple olson IDs to choose
// from and the use of a zone's long name leads to ambiguity. For example, at the time of
// writing Android lists 5 olson ids for Australia which collapse to 2 different zone names
// in winter but 4 different zone names in summer. The ambiguity leads to the users
// selecting the wrong olson ids.
// Get the list of olson ids to display to the user.
List<String> olsonIdsToDisplayList = readTimezonesToDisplay(context);
// Store the information we are going to need more than once.
final int zoneCount = olsonIdsToDisplayList.size();
final String[] olsonIdsToDisplay = new String[zoneCount];
final TimeZone[] timeZones = new TimeZone[zoneCount];
final String[] gmtOffsetStrings = new String[zoneCount];
for (int i = 0; i < zoneCount; i++) {
String olsonId = olsonIdsToDisplayList.get(i);
olsonIdsToDisplay[i] = olsonId;
TimeZone tz = TimeZone.getTimeZone(olsonId);
timeZones[i] = tz;
gmtOffsetStrings[i] = getGmtOffsetString(locale, tz, now);
}
// Create a lookup of local zone IDs.
Set<String> localZoneIds = new HashSet<String>();
for (String olsonId : libcore.icu.TimeZoneNames.forLocale(locale)) {
localZoneIds.add(olsonId);
}
// Work out whether the display names we would show by default would be ambiguous.
Set<String> localZoneNames = new HashSet<String>();
boolean useExemplarLocationForLocalNames = false;
for (int i = 0; i < zoneCount; i++) {
String olsonId = olsonIdsToDisplay[i];
if (localZoneIds.contains(olsonId)) {
TimeZone tz = timeZones[i];
String displayName = getZoneLongName(timeZoneNames, tz, now);
if (displayName == null) {
displayName = gmtOffsetStrings[i];
}
boolean nameIsUnique = localZoneNames.add(displayName);
if (!nameIsUnique) {
useExemplarLocationForLocalNames = true;
break;
}
}
}
// Generate the list of zone entries to return.
List<Map<String, Object>> zones = new ArrayList<Map<String, Object>>();
for (int i = 0; i < zoneCount; i++) {
String olsonId = olsonIdsToDisplay[i];
TimeZone tz = timeZones[i];
String gmtOffsetString = gmtOffsetStrings[i];
boolean isLocalZoneId = localZoneIds.contains(olsonId);
boolean preferLongName = isLocalZoneId && !useExemplarLocationForLocalNames;
String displayName;
if (preferLongName) {
displayName = getZoneLongName(timeZoneNames, tz, now);
} else {
displayName = timeZoneNames.getExemplarLocationName(tz.getID());
if (displayName == null || displayName.isEmpty()) {
// getZoneExemplarLocation can return null. Fall back to the long name.
displayName = getZoneLongName(timeZoneNames, tz, now);
}
}
if (displayName == null || displayName.isEmpty()) {
displayName = gmtOffsetString;
}
int offsetMillis = tz.getOffset(now.getTime());
Map<String, Object> displayEntry =
createDisplayEntry(tz, gmtOffsetString, displayName, offsetMillis);
zones.add(displayEntry);
}
return zones;
}
private static Map<String, Object> createDisplayEntry(
TimeZone tz, String gmtOffsetString, String displayName, int offsetMillis) {
Map<String, Object> map = new HashMap<String, Object>();
map.put(KEY_ID, tz.getID());
map.put(KEY_DISPLAYNAME, displayName);
map.put(KEY_GMT, gmtOffsetString);
map.put(KEY_OFFSET, offsetMillis);
return map;
}
private static List<String> readTimezonesToDisplay(Context context) {
List<String> olsonIds = new ArrayList<String>();
try (XmlResourceParser xrp = context.getResources().getXml(R.xml.timezones)) {
while (xrp.next() != XmlResourceParser.START_TAG) {
continue;
}
xrp.next();
while (xrp.getEventType() != XmlResourceParser.END_TAG) {
while (xrp.getEventType() != XmlResourceParser.START_TAG) {
if (xrp.getEventType() == XmlResourceParser.END_DOCUMENT) {
return olsonIds;
}
xrp.next();
}
if (xrp.getName().equals(XMLTAG_TIMEZONE)) {
String olsonId = xrp.getAttributeValue(0);
olsonIds.add(olsonId);
}
while (xrp.getEventType() != XmlResourceParser.END_TAG) {
xrp.next();
}
xrp.next();
}
} catch (XmlPullParserException xppe) {
Log.e(TAG, "Ill-formatted timezones.xml file");
} catch (java.io.IOException ioe) {
Log.e(TAG, "Unable to read timezones.xml file");
}
return olsonIds;
}
/**
* Returns the long name for the timezone for the given locale at the time specified.
* Can return {@code null}.
*/
private static String getZoneLongName(TimeZoneNames names, TimeZone tz, Date now) {
TimeZoneNames.NameType nameType =
tz.inDaylightTime(now) ? TimeZoneNames.NameType.LONG_DAYLIGHT
: TimeZoneNames.NameType.LONG_STANDARD;
return names.getDisplayName(tz.getID(), nameType, now.getTime());
}
private static String getGmtOffsetString(Locale locale, TimeZone tz, Date now) {
// Use SimpleDateFormat to format the GMT+00:00 string.
SimpleDateFormat gmtFormatter = new SimpleDateFormat("ZZZZ");
gmtFormatter.setTimeZone(tz);
String gmtString = gmtFormatter.format(now);
// Ensure that the "GMT+" stays with the "00:00" even if the digits are RTL.
BidiFormatter bidiFormatter = BidiFormatter.getInstance();
boolean isRtl = TextUtils.getLayoutDirectionFromLocale(locale) == View.LAYOUT_DIRECTION_RTL;
gmtString = bidiFormatter.unicodeWrap(gmtString,
isRtl ? TextDirectionHeuristics.RTL : TextDirectionHeuristics.LTR);
return gmtString;
}
}