How to find out GMT offset value in android

Question

How to find out the values of GMT for user for example it is +05:30 for India. How do calculate this +05:30 value in Android ?

I need this because I am using a java library in my app which has a function with this +05:30 field and I want to generate this field by calculation so that I wont have to fill up individual values for countries.

Answer 1

This is what works awesome

   public double getOffset(){
        TimeZone timezone = TimeZone.getDefault();
        int seconds = timezone.getOffset(Calendar.ZONE_OFFSET)/1000;
        double minutes = seconds/60;
        double hours = minutes/60;
        return hours;
  }

Answer 2

First get the epoch system time

System.currentTimeMillis()

Then use a date object, set the time zone to GMT and initialize with the long valye

dateObj.setTimeZone(TimeZone.getTimeZone("GMT"))

Answer 3

To get time in GMT use below function where dateInString is the value of date,and format is date format as yyyyMMddHH

   public static long getDate(String dateInString,String format){
       long date = 0;
       SimpleDateFormat dateFormat = new SimpleDateFormat(format);

       try {
        dateFormat.setTimeZone(TimeZone.getTimeZone("GMT"));
        Date d = dateFormat.parse(dateInString);
        date = d.getTime();
       } catch (ParseException e) {
        e.printStackTrace();
       }

       return date;
   }

Answer 4

Use below method to get UTC :-

public int GetUnixTime()
{
    Calendar calendar = Calendar.getInstance();
    long now = calendar.getTimeInMillis();
    int utc = (int)(now / 1000);
    return (utc);

}

after you get UTC now compared it to the Epoch in this site http://www.xav.com/time.cgi.

see this below link :-

How can I get the current date and time in UTC or GMT in Java?

Answer 5

If you store a map between timezones and their GMT offsets in your app, you can call TimeZone.getDefault() to get the device's timezone and do a quick lookup to return the GMT offset. That way you don't have to rely on potentially tricky date/time calculations and can be sure you have the correct value.