How to get time with respect to another timezone in android [duplicate]

Question

I want to create an alarm application for FIFA 2014 world cup matches in which i have a server which stores the date and time for the matches in Brazil/Acre and my client is an android application and an android device may have any of the possible timezone so the my problem is i want to convert the Brazil/Acre timing to the local android device timing with different timezone and after lot of googled i came to know about joda data and time lib but it is too slow in android so please suggest any code that will work for me.

Answer 1

In my opinion Time class is the best for your job. Also it is Android API not general Java API.

Here I mentioned some of useful methods for your job:

void switchTimezone(String timezone)

Convert this time object so the time represented remains the same, but is instead located in a different timezone.

static String getCurrentTimezone()

Returns the timezone string that is currently set for the device.

And if you want to save a time in a timezone independed manner, you can convert to milliseconds (in UTC) by toMillis() method and then retrieve it by set(long millis) method.

If something is unclear please tell me!

UPDATE

Example:

long timeMillis = /* get time milliseconds form the server */
Time time = new Time();
time.set(timeMillis);

/* changing time zone */
time.switchTimezone(/* your desired timezone in string format */);

/* getting time as string  */
String timeString = time.format("%Y%m%dT%H%M%S"); // you can change format as you wish

Here is a table for formatting times

Answer 2

You could use this code, which substracts the hour-difference between Brazil and the local timezone. Just replace yourDate with a Date-object.

//code...
yourDate.setTime(yourDate.getTime() - getDifferenceInMillis());
//code...

public int getDifferenceInMillis() {
    // Local Time
    int localMinute = Calendar.getInstance().get(Calendar.MINUTE);
    int localHour = Calendar.getInstance().get(Calendar.HOUR_OF_DAY);
    int localDay = Calendar.getInstance().get(Calendar.DAY_OF_MONTH);

    // Brazil Time
    Calendar c = new GregorianCalendar(TimeZone.getTimeZone("Brazil/Acre"));
    c.setTimeInMillis(new Date().getTime());
    int brazilMinute = c.get(Calendar.MINUTE);
    int brazilHour = c.get(Calendar.HOUR_OF_DAY);
    int brazilDay = c.get(Calendar.DAY_OF_MONTH);

    // Difference between Brazil and local
    int minuteDifference = brazilMinute - localMinute;
    int hourDifference = brazilHour - localHour;
    int dayDifference = brazilDay - localDay;
    if (dayDifference != 0) {
        hourDifference = hourDifference + 24;
    }
    return (hourDifference * 60 + minuteDifference) * 60 * 1000;
}