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Android example source code file (TimeUtils.java)

This example Android source code file (TimeUtils.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" TM.

Java - Android tags/keywords

android, content, date, got, io, ioexception, resources, string, tag, timeutils, timezone, util, utilities, utils, xmlpullparserexception, xmlresourceparser

The TimeUtils.java Android example source code

/*
 * Copyright (C) 2006 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 android.util;

import android.content.res.Resources;
import android.content.res.XmlResourceParser;

import org.apache.harmony.luni.internal.util.ZoneInfoDB;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import java.io.IOException;
import java.util.TimeZone;
import java.util.Date;

import com.android.internal.util.XmlUtils;

/**
 * A class containing utility methods related to time zones.
 */
public class TimeUtils {
    private static final String TAG = "TimeUtils";

    /**
     * Tries to return a time zone that would have had the specified offset
     * and DST value at the specified moment in the specified country.
     * Returns null if no suitable zone could be found.
     */
    public static TimeZone getTimeZone(int offset, boolean dst, long when, String country) {
        if (country == null) {
            return null;
        }

        TimeZone best = null;

        Resources r = Resources.getSystem();
        XmlResourceParser parser = r.getXml(com.android.internal.R.xml.time_zones_by_country);
        Date d = new Date(when);

        TimeZone current = TimeZone.getDefault();
        String currentName = current.getID();
        int currentOffset = current.getOffset(when);
        boolean currentDst = current.inDaylightTime(d);

        try {
            XmlUtils.beginDocument(parser, "timezones");

            while (true) {
                XmlUtils.nextElement(parser);

                String element = parser.getName();
                if (element == null || !(element.equals("timezone"))) {
                    break;
                }

                String code = parser.getAttributeValue(null, "code");

                if (country.equals(code)) {
                    if (parser.next() == XmlPullParser.TEXT) {
                        String maybe = parser.getText();

                        // If the current time zone is from the right country
                        // and meets the other known properties, keep it
                        // instead of changing to another one.

                        if (maybe.equals(currentName)) {
                            if (currentOffset == offset && currentDst == dst) {
                                return current;
                            }
                        }

                        // Otherwise, take the first zone from the right
                        // country that has the correct current offset and DST.
                        // (Keep iterating instead of returning in case we
                        // haven't encountered the current time zone yet.)

                        if (best == null) {
                            TimeZone tz = TimeZone.getTimeZone(maybe);

                            if (tz.getOffset(when) == offset &&
                                tz.inDaylightTime(d) == dst) {
                                best = tz;
                            }
                        }
                    }
                }
            }
        } catch (XmlPullParserException e) {
            Log.e(TAG, "Got exception while getting preferred time zone.", e);
        } catch (IOException e) {
            Log.e(TAG, "Got exception while getting preferred time zone.", e);
        } finally {
            parser.close();
        }

        return best;
    }

    /**
     * Returns a String indicating the version of the time zone database currently
     * in use.  The format of the string is dependent on the underlying time zone
     * database implementation, but will typically contain the year in which the database
     * was updated plus a letter from a to z indicating changes made within that year.
     * 
     * <p>Time zone database updates should be expected to occur periodically due to
     * political and legal changes that cannot be anticipated in advance.  Therefore,
     * when computing the UTC time for a future event, applications should be aware that
     * the results may differ following a time zone database update.  This method allows
     * applications to detect that a database change has occurred, and to recalculate any
     * cached times accordingly.
     * 
     * <p>The time zone database may be assumed to change only when the device runtime
     * is restarted.  Therefore, it is not necessary to re-query the database version
     * during the lifetime of an activity.
     */
    public static String getTimeZoneDatabaseVersion() {
        return ZoneInfoDB.getVersion();
    }
}

Other Android examples (source code examples)

Here is a short list of links related to this Android TimeUtils.java source code file:

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