/*
* 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.text.BidiFormatter;
import android.text.TextDirectionHeuristics;
import android.text.TextUtils;
import android.util.Log;
import android.view.View;
import com.android.settingslib.R;
import libcore.icu.TimeZoneNames;
import org.xmlpull.v1.XmlPullParserException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.TimeZone;
import java.util.TreeSet;
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);
String zoneNameString = getZoneLongName(locale, 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();
// 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> olsonIdsToDisplay = readTimezonesToDisplay(context);
// Create a lookup of local zone IDs.
Set<String> localZoneIds = new TreeSet<String>();
for (String olsonId : TimeZoneNames.forLocale(locale)) {
localZoneIds.add(olsonId);
}
// Work out whether the long names for the local entries that we would show by default would
// be ambiguous.
Set<String> localZoneNames = new TreeSet<String>();
boolean localLongNamesAreAmbiguous = false;
for (String olsonId : olsonIdsToDisplay) {
if (localZoneIds.contains(olsonId)) {
TimeZone tz = TimeZone.getTimeZone(olsonId);
String zoneLongName = getZoneLongName(locale, tz, now);
boolean longNameIsUnique = localZoneNames.add(zoneLongName);
if (!longNameIsUnique) {
localLongNamesAreAmbiguous = true;
break;
}
}
}
// Generate the list of zone entries to return.
List<Map<String, Object>> zones = new ArrayList<Map<String, Object>>();
for (String olsonId : olsonIdsToDisplay) {
final TimeZone tz = TimeZone.getTimeZone(olsonId);
// Exemplar location display is the default. The only time we intend to display the long
// name is when the olsonId is local AND long names are not ambiguous.
boolean isLocalZoneId = localZoneIds.contains(olsonId);
boolean preferLongName = isLocalZoneId && !localLongNamesAreAmbiguous;
String displayName = getZoneDisplayName(locale, tz, now, preferLongName);
String gmtOffsetString = getGmtOffsetString(locale, tz, now);
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;
}
/**
* Returns a name for the specific zone. If {@code preferLongName} is {@code true} then the
* long display name for the timezone will be used, otherwise the exemplar location will be
* preferred.
*/
private static String getZoneDisplayName(Locale locale, TimeZone tz, Date now,
boolean preferLongName) {
String zoneNameString;
if (preferLongName) {
zoneNameString = getZoneLongName(locale, tz, now);
} else {
zoneNameString = getZoneExemplarLocation(locale, tz);
if (zoneNameString == null || zoneNameString.isEmpty()) {
// getZoneExemplarLocation can return null.
zoneNameString = getZoneLongName(locale, tz, now);
}
}
return zoneNameString;
}
private static String getZoneExemplarLocation(Locale locale, TimeZone tz) {
return TimeZoneNames.getExemplarLocation(locale.toString(), tz.getID());
}
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;
}
private static String getZoneLongName(Locale locale, TimeZone tz, Date now) {
boolean daylight = tz.inDaylightTime(now);
// This returns a name if it can, or will fall back to GMT+0X:00 format.
return tz.getDisplayName(daylight, TimeZone.LONG, locale);
}
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;
}
}