Dayerman Dayerman - 1 year ago 72
Android Question

Getting GMT time with Android

I have been digging into the question for a while in StackOverflow
Android get Current UTC time
How can I get the current date and time in UTC or GMT in Java?

I have tried two ways to get the current time of my phone in GMT. I am in Spain and the difference is GMT+2. So let's see with an example:
1ยบ attemp: I created a format and applied it to System.currentTimeMillis();

DateFormat dfgmt = new java.text.SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
String gmtTime = dfgmt.format(new Date());
//Using System.currentTimeMillis() is the same as new Date()
Date dPhoneTime = dfgmt.parse(gmtTime);
Long phoneTimeUTC = dPhoneTime.getTime();

I need to substract that time to another time, that's why i do the cast to Long.

DateFormat df = new java.text.SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
Date arrivalDate = df.parse(item.getArrivalDate());
//the String comes from JSON and is for example:"UTC_arrival":"2011-05-16 18:00:00"
//which already is in UTC format. So the DateFormat doesnt have the GMT paramater as dfgmt
diff = arrival.getTime() - phoneTimeUTC ;

I also tried this:

Calendar aGMTCalendar = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
Long phoneTimeUTC = aGMTCalendar.getTimeInMillis()

And still I dont get the right difference. But if I do this:

Long phoneTimeUTC = aGMTCalendar.getTimeInMillis()-3600000*2;

It does work OK.

Any ideas?

Thanks a lot,


Answer Source

As far as I read the calendar.getTimeInMillis(); returns the UTC time in millis. I used the following code and compared it to the Epoch in this site

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



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