How to convert UTC timestamp to device local time in android

Question

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 server the post

Answer 1

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.

Answer 2

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;
}

Answer 3

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.

Answer 4

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();

Answer 5

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();
}

Answer 6

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);
  }
}