The function gives time difference between local time and time sent from server in the format that is readable to human, i.e, "3 hours ago", "1 day ago" etc.

Human Time Difference in Android

public String processTime(String s) {

        // parse server time
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd kk:mm:ss");
        Date reviewDate = null;
        try {
            reviewDate = sdf.parse(s);
        }catch(Exception ex){
            ex.printStackTrace();
        }

        // get present time
        Calendar cal = Calendar.getInstance();
        Date presentDate = cal.getTime();

        // get timezone difference
        Calendar mCalendar = new GregorianCalendar();
        TimeZone mTimeZone = mCalendar.getTimeZone();
        int mGMTOffset = mTimeZone.getRawOffset();
        //long value = TimeUnit.HOURS.convert(mGMTOffset, TimeUnit.MILLISECONDS);

        //difference between server time and current time, minus timezone, in milliseconds
        // server: GMT, present: LOCALTIME
        long difference = presentDate.getTime() - reviewDate.getTime() - mGMTOffset;

        // just log input times
        System.out.println("presentDate : " + presentDate);
        System.out.println("reviewDate : "+ reviewDate);
        System.out.println("different : " + difference);
        
        // now, format the text according to difference
        long secondsInMilli = 1000;
        long minutesInMilli = secondsInMilli * 60;
        long hoursInMilli = minutesInMilli * 60;
        long daysInMilli = hoursInMilli * 24;
        long monthsInMilli = daysInMilli * 30;
        long yearsInMilli = monthsInMilli * 12;

        long elapsedYears = difference / yearsInMilli;
        difference = difference % yearsInMilli;

        long elapsedMonths = difference / monthsInMilli;
        difference = difference % monthsInMilli;

        long elapsedDays = difference / daysInMilli;
        difference = difference % daysInMilli;

        long elapsedHours = difference / hoursInMilli;
        difference = difference % hoursInMilli;

        long elapsedMinutes = difference / minutesInMilli;
        difference = difference % minutesInMilli;

        long elapsedSeconds = difference / secondsInMilli;

        System.out.printf(
                "%d years, %d months, %d days, %d hours, %d minutes, %d seconds%n",
                elapsedYears, elapsedMonths ,elapsedDays, elapsedHours, elapsedMinutes, elapsedSeconds);

        String differenceText = "0 second ago";

        if (elapsedYears > 0) {
            if (elapsedYears == 1)
                differenceText = elapsedYears + " year ago";
            else
                differenceText = elapsedYears + " years ago";
        } else if (elapsedMonths > 0) {
            if (elapsedMonths == 1)
                differenceText = elapsedMonths + " month ago";
            else
                differenceText = elapsedMonths + " months ago";
        } else if (elapsedDays > 0) {
            if (elapsedDays == 1)
                differenceText = elapsedDays + " day ago";
            else
                differenceText = elapsedDays + " days ago";
        } else if (elapsedHours > 0) {
            if (elapsedHours == 1)
                differenceText = elapsedHours + " hour ago";
            else
                differenceText = elapsedHours + " hours ago";
        } else if (elapsedMinutes > 0) {
            if (elapsedMinutes == 1)
                differenceText = elapsedMinutes + " minute ago";
            else
                differenceText = elapsedMinutes + " minutes ago";
        } else if (elapsedSeconds > 0) {
            if (elapsedSeconds == 1)
                differenceText = elapsedSeconds + " second ago";
            else
                differenceText = elapsedSeconds + " seconds ago";
        }

        return differenceText;
    }