How to convert UTC timestamp to device local time in android

I need to convert the UTC time stamp that I get from the server to local device time. Currently, I get 5 hrs difference in my time. For example, when I post to the server, the post time says 5 hours ago instead of a second ago. How could I fix this issue?

Below is the code that I do:

long timestamp = cursor.getLong(columnIndex);
			CharSequence relTime = DateUtils
					.getRelativeTimeSpanString(timestamp * 1000
							+ TimeZone.getDefault().getRawOffset(),
							System.currentTimeMillis(),
							DateUtils.MINUTE_IN_MILLIS);
			((TextView) view).setText(relTime);

Java:

int offset = TimeZone.getDefault().getRawOffset() + TimeZone.getDefault().getDSTSavings();
long now = System.currentTimeMillis() - offset;

Kotlin:

val offset: Int = TimeZone.getDefault().rawOffset + TimeZone.getDefault().dstSavings
val now: Long = System.currentTimeMillis() - offset

Converting a date String of the format "2011-06-23T15:11:32" to our time zone.

private String getDate(String ourDate)
{
    try
    {
        SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        formatter.setTimeZone(TimeZone.getTimeZone("UTC"));
        Date value = formatter.parse(ourDate);

        SimpleDateFormat dateFormatter = new SimpleDateFormat("MM-dd-yyyy HH:mm"); //this format changeable
        dateFormatter.setTimeZone(TimeZone.getDefault());
        ourDate = dateFormatter.format(value);

        //Log.d("ourDate", ourDate);
    }
    catch (Exception e)
    {
        ourDate = "00-00-0000 00:00";
    }
  return ourDate;
}

The code in your example looks fine at first glance. BTW, if the server timestamp is in UTC (i.e. it's an epoch timestamp) then you should not have to apply the current timezone offset. In other words if the server timestamp is in UTC then you can simply get the difference between the server timestamp and the system time (System.currentTimeMillis()) as the system time is in UTC (epoch).

I would check that the timestamp coming from your server is what you expect. If the timestamp from the server does not convert into the date you expect (in the local timezone) then the difference between the timestamp and the current system time will not be what you expect.

Use Calendar to get the current timezone. Initialize a SimpleDateFormatter with the current timezone; then log the server timestamp and verify if it's the date you expect:

Calendar cal = Calendar.getInstance();
TimeZone tz = cal.getTimeZone();




/* debug: is it local time? */
Log.d("Time zone: ", tz.getDisplayName());




/* date formatter in local timezone */
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy HH:mm:ss");
sdf.setTimeZone(tz);




/* print your timestamp and double check it's the date you expect */
long timestamp = cursor.getLong(columnIndex);
String localTime = sdf.format(new Date(timestamp * 1000)); // I assume your timestamp is in seconds and you're converting to milliseconds?
Log.d("Time: ", localTime);
/* print your timestamp and double check it's the date you expect */
long timestamp = cursor.getLong(columnIndex);
String localTime = sdf.format(new Date(timestamp * 1000)); // I assume your timestamp is in seconds and you're converting to milliseconds?
Log.d("Time: ", localTime);

If the server time that is printed is not what you expect then your server time is not in UTC.

If the server time that is printed is the date that you expect then you should not have to apply the rawoffset to it. So your code would be simpler (minus all the debug logging):

long timestamp = cursor.getLong(columnIndex);
Log.d("Server time: ", timestamp);




/* log the device timezone */
Calendar cal = Calendar.getInstance();
TimeZone tz = cal.getTimeZone();
Log.d("Time zone: ", tz.getDisplayName());




/* log the system time */
Log.d("System time: ", System.currentTimeMillis());




CharSequence relTime = DateUtils.getRelativeTimeSpanString(
timestamp * 1000,
System.currentTimeMillis(),
DateUtils.MINUTE_IN_MILLIS);




((TextView) view).setText(relTime);
((TextView) view).setText(relTime);

I did it using Extension Functions in kotlin

fun String.toDate(dateFormat: String = "yyyy-MM-dd HH:mm:ss", timeZone: TimeZone = TimeZone.getTimeZone("UTC")): Date {
	val parser = SimpleDateFormat(dateFormat, Locale.getDefault())
	parser.timeZone = timeZone
	return parser.parse(this)
}

fun Date.formatTo(dateFormat: String, timeZone: TimeZone = TimeZone.getDefault()): String {
	val formatter = SimpleDateFormat(dateFormat, Locale.getDefault())
	formatter.timeZone = timeZone
	return formatter.format(this)
}

Usage:

"2018-09-10 22:01:00".toDate().formatTo("dd MMM yyyy")

Output: "11 Sep 2018"

Note:

Ensure the proper validation.

java.time

The java.util Date-Time API and their formatting API, SimpleDateFormat are outdated and error-prone. It is recommended to stop using them completely and switch to the modern Date-Time API^*.

Solution using java.time, the modern Date-Time API:

import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneId;

public class Main {
	public static void main(String[] args) {
		// A sample timestamp as Unix epoch (i.e. seconds from 01-01-1970T00:00:00 GMT)
		long epochSeconds = 1632131465L;

		// Note: Use Instant#ofEpochMilli in case you have timestamp in milliseconds
		Instant instant = Instant.ofEpochSecond(epochSeconds);
		System.out.println(instant);

		LocalDateTime ldt = LocalDateTime.ofInstant(instant, ZoneId.systemDefault());
		System.out.println(ldt);
	}
}

Output in my timezone, Europe/London:

2021-09-20T09:51:05Z
2021-09-20T10:51:05

ONLINE DEMO

An Instant represents an instantaneous point on the timeline, normally represented in UTC time. The Z in the output is the timezone designator for a zero-timezone offset. It stands for Zulu and specifies the Etc/UTC timezone (which has the timezone offset of +00:00 hours).

Learn more about the modern Date-Time API from Trail: Date Time.

---

^{* For any reason, if you have to stick to Java 6 or Java 7, you can use ThreeTen-Backport which backports most of the java.time functionality to Java 6 & 7. If you are working for an Android project and your Android API level is still not compliant with Java-8, check Java 8+ APIs available through desugaring and How to use ThreeTenABP in Android Project.}

I have do something like this to get date in local device timezone from UTC time stamp.

private long UTC_TIMEZONE=1470960000;
private String OUTPUT_DATE_FORMATE="dd-MM-yyyy - hh:mm a"

getDateFromUTCTimestamp(UTC_TIMEZONE,OUTPUT_DATE_FORMATE);

Here is the function

 public String getDateFromUTCTimestamp(long mTimestamp, String mDateFormate) {
        String date = null;
        try {
            Calendar cal = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
            cal.setTimeInMillis(mTimestamp * 1000L);
            date = DateFormat.format(mDateFormate, cal.getTimeInMillis()).toString();

            SimpleDateFormat formatter = new SimpleDateFormat(mDateFormate);
            formatter.setTimeZone(TimeZone.getTimeZone("UTC"));
            Date value = formatter.parse(date);

            SimpleDateFormat dateFormatter = new SimpleDateFormat(mDateFormate);
            dateFormatter.setTimeZone(TimeZone.getDefault());
            date = dateFormatter.format(value);
            return date;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return date;
    }

Result :

12-08-2016 - 04:30 PM 

Hope this will work for others.

Local to UTC

DateTime dateTimeNew = new DateTime(date.getTime(),
DateTimeZone.forID("Asia/Calcutta"));
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
simpleDateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
String datetimeString = dateTimeNew.toString("yyyy-MM-dd HH:mm:ss");
long milis = 0;
try {
     milis = simpleDateFormat.parse(datetimeString).getTime();
} catch (ParseException e) {
   e.printStackTrace();
}

The answer from @prgDevelop returns 0 on my Android Marsmallow. Must return 7200000. These changes make it work fine:

int offset = TimeZone.getTimeZone(Time.getCurrentTimezone()).getRawOffset() + TimeZone.getTimeZone(Time.getCurrentTimezone()).getDSTSavings();

This may help some one with same requirement

private String getDate(long time){
        SimpleDateFormat formatter = new SimpleDateFormat("dd/MM/yyyy hh:mm a");
        String dateString = formatter.format(new Date(time));
        String date = ""+dateString;
        return date;
    }

I had a similar problem. Simply set your utc timestamp to your timezone calendar and format the date. Timestamp is still the same no matter timezone.

val local = Calendar.getInstance()   // get your device timezone calendar
local.timeInMillis = <timestamp>

val sdf = SimpleDateFormat("dd/MM/yyyy HH:mm:ss")
val formatted = sdf.format(Date(local.timeInMillis))

It's Working

Call this method where you use

SntpClient client = new SntpClient();
if (client.requestTime("ntp.ubuntu.com", 30000)) {
  long now = client.getNtpTime();
  Date current = new Date(now);

  date2 = sdf.parse(new Date(current.getTime()).toString());
 // System.out.println(current.toString());
  Log.e(TAG, "testing SntpClient time current.toString() "+current.toString()+" , date2 = "+date2);
}

=====================================================   

import android.os.SystemClock;
import android.util.Log;

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

/**
 * {@hide}
 *
 * Simple SNTP client class for retrieving network time.
 *
 * Sample usage:
 * <pre>SntpClient client = new SntpClient();
 * if (client.requestTime("time.foo.com")) {
 *     long now = client.getNtpTime() + SystemClock.elapsedRealtime() - client.getNtpTimeReference();
 * }
 * </pre>
 */
public class SntpClient
{
  private static final String TAG = "SntpClient";

  private static final int REFERENCE_TIME_OFFSET = 16;
  private static final int ORIGINATE_TIME_OFFSET = 24;
  private static final int RECEIVE_TIME_OFFSET = 32;
  private static final int TRANSMIT_TIME_OFFSET = 40;
  private static final int NTP_PACKET_SIZE = 48;

  private static final int NTP_PORT = 123;
  private static final int NTP_MODE_CLIENT = 3;
  private static final int NTP_VERSION = 3;

  // Number of seconds between Jan 1, 1900 and Jan 1, 1970
  // 70 years plus 17 leap days
  private static final long OFFSET_1900_TO_1970 = ((365L * 70L) + 17L) * 24L * 60L * 60L;

  // system time computed from NTP server response
  private long mNtpTime;

  // value of SystemClock.elapsedRealtime() corresponding to mNtpTime
  private long mNtpTimeReference;

  // round trip time in milliseconds
  private long mRoundTripTime;

  /**
   * Sends an SNTP request to the given host and processes the response.
   *
   * @param host host name of the server.
   * @param timeout network timeout in milliseconds.
   * @return true if the transaction was successful.
   */
  public boolean requestTime(String host, int timeout) {
    DatagramSocket socket = null;
    try {
      socket = new DatagramSocket();
      socket.setSoTimeout(timeout);
      InetAddress address = InetAddress.getByName(host);
      byte[] buffer = new byte[NTP_PACKET_SIZE];
      DatagramPacket request = new DatagramPacket(buffer, buffer.length, address, NTP_PORT);

      // set mode = 3 (client) and version = 3
      // mode is in low 3 bits of first byte
      // version is in bits 3-5 of first byte
      buffer[0] = NTP_MODE_CLIENT | (NTP_VERSION << 3);

      // get current time and write it to the request packet
      long requestTime = System.currentTimeMillis();
      long requestTicks = SystemClock.elapsedRealtime();
      writeTimeStamp(buffer, TRANSMIT_TIME_OFFSET, requestTime);

      socket.send(request);

      // read the response
      DatagramPacket response = new DatagramPacket(buffer, buffer.length);
      socket.receive(response);
      long responseTicks = SystemClock.elapsedRealtime();
      long responseTime = requestTime + (responseTicks - requestTicks);

      // extract the results
      long originateTime = readTimeStamp(buffer, ORIGINATE_TIME_OFFSET);
      long receiveTime = readTimeStamp(buffer, RECEIVE_TIME_OFFSET);
      long transmitTime = readTimeStamp(buffer, TRANSMIT_TIME_OFFSET);
      long roundTripTime = responseTicks - requestTicks - (transmitTime - receiveTime);
      // receiveTime = originateTime + transit + skew
      // responseTime = transmitTime + transit - skew
      // clockOffset = ((receiveTime - originateTime) + (transmitTime - responseTime))/2
      //             = ((originateTime + transit + skew - originateTime) +
      //                (transmitTime - (transmitTime + transit - skew)))/2
      //             = ((transit + skew) + (transmitTime - transmitTime - transit + skew))/2
      //             = (transit + skew - transit + skew)/2
      //             = (2 * skew)/2 = skew
      long clockOffset = ((receiveTime - originateTime) + (transmitTime - responseTime))/2;
      // if (false) Log.d(TAG, "round trip: " + roundTripTime + " ms");
      // if (false) Log.d(TAG, "clock offset: " + clockOffset + " ms");

      // save our results - use the times on this side of the network latency
      // (response rather than request time)
      mNtpTime = responseTime + clockOffset;
      mNtpTimeReference = responseTicks;
      mRoundTripTime = roundTripTime;
    } catch (Exception e) {
      if (false) Log.d(TAG, "request time failed: " + e);
      return false;
    } finally {
      if (socket != null) {
        socket.close();
      }
    }

    return true;
  }

  /**
   * Returns the time computed from the NTP transaction.
   *
   * @return time value computed from NTP server response.
   */
  public long getNtpTime() {
    return mNtpTime;
  }

  /**
   * Returns the reference clock value (value of SystemClock.elapsedRealtime())
   * corresponding to the NTP time.
   *
   * @return reference clock corresponding to the NTP time.
   */
  public long getNtpTimeReference() {
    return mNtpTimeReference;
  }

  /**
   * Returns the round trip time of the NTP transaction
   *
   * @return round trip time in milliseconds.
   */
  public long getRoundTripTime() {
    return mRoundTripTime;
  }

  /**
   * Reads an unsigned 32 bit big endian number from the given offset in the buffer.
   */
  private long read32(byte[] buffer, int offset) {
    byte b0 = buffer[offset];
    byte b1 = buffer[offset+1];
    byte b2 = buffer[offset+2];
    byte b3 = buffer[offset+3];

    // convert signed bytes to unsigned values
    int i0 = ((b0 & 0x80) == 0x80 ? (b0 & 0x7F) + 0x80 : b0);
    int i1 = ((b1 & 0x80) == 0x80 ? (b1 & 0x7F) + 0x80 : b1);
    int i2 = ((b2 & 0x80) == 0x80 ? (b2 & 0x7F) + 0x80 : b2);
    int i3 = ((b3 & 0x80) == 0x80 ? (b3 & 0x7F) + 0x80 : b3);

    return ((long)i0 << 24) + ((long)i1 << 16) + ((long)i2 << 8) + (long)i3;
  }

  /**
   * Reads the NTP time stamp at the given offset in the buffer and returns
   * it as a system time (milliseconds since January 1, 1970).
   */
  private long readTimeStamp(byte[] buffer, int offset) {
    long seconds = read32(buffer, offset);
    long fraction = read32(buffer, offset + 4);
    return ((seconds - OFFSET_1900_TO_1970) * 1000) + ((fraction * 1000L) / 0x100000000L);
  }

  /**
   * Writes system time (milliseconds since January 1, 1970) as an NTP time stamp
   * at the given offset in the buffer.
   */
  private void writeTimeStamp(byte[] buffer, int offset, long time) {
    long seconds = time / 1000L;
    long milliseconds = time - seconds * 1000L;
    seconds += OFFSET_1900_TO_1970;

    // write seconds in big endian format
    buffer[offset++] = (byte)(seconds >> 24);
    buffer[offset++] = (byte)(seconds >> 16);
    buffer[offset++] = (byte)(seconds >> 8);
    buffer[offset++] = (byte)(seconds >> 0);

    long fraction = milliseconds * 0x100000000L / 1000L;
    // write fraction in big endian format
    buffer[offset++] = (byte)(fraction >> 24);
    buffer[offset++] = (byte)(fraction >> 16);
    buffer[offset++] = (byte)(fraction >> 8);
    // low order bits should be random data
    buffer[offset++] = (byte)(Math.random() * 255.0);
  }
}