如何从 android 设备获取 GMT 时区偏移量（如 GMT+7:00）？

Question

I am getting the timezone of a android device using this code

TimeZone tz = TimeZone.getDefault();
String current_Time_Zone = (TimeZone.getTimeZone(tz.getID()).getDisplayName(
                false, TimeZone.SHORT))

But it always return me the timezone like " IST " but i want to get the timezone in GMT like this GMT+7:00.

Answer 1

This might give you an idea on how to implement it to your liking:

Calendar mCalendar = new GregorianCalendar();  
TimeZone mTimeZone = mCalendar.getTimeZone();  
int mGMTOffset = mTimeZone.getRawOffset();  
System.out.printf("GMT offset is %s hours", TimeUnit.HOURS.convert(mGMTOffset, TimeUnit.MILLISECONDS)); 

(TimeUnit is "java.util.concurrent.TimeUnit")

Answer 2

This code return me GMT offset.

Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("GMT"),
                Locale.getDefault());
Date currentLocalTime = calendar.getTime();
DateFormat date = new SimpleDateFormat("Z");
String localTime = date.format(currentLocalTime);

It returns the time zone offset like this: +0530

If we use SimpleDateFormat below

DateFormat date = new SimpleDateFormat("z",Locale.getDefault());
String localTime = date.format(currentLocalTime);

It returns the time zone offset like this: GMT+05:30

Answer 3

Here is a solution to get timezone offset in GMT+05:30 this format

public String getCurrentTimezoneOffset() {

    TimeZone tz = TimeZone.getDefault();  
    Calendar cal = GregorianCalendar.getInstance(tz);
    int offsetInMillis = tz.getOffset(cal.getTimeInMillis());

    String offset = String.format("%02d:%02d", Math.abs(offsetInMillis / 3600000), Math.abs((offsetInMillis / 60000) % 60));
    offset = "GMT"+(offsetInMillis >= 0 ? "+" : "-") + offset;

    return offset;
}

Answer 4

public static String timeZone()
{
    Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("GMT"), Locale.getDefault());
    String   timeZone = new SimpleDateFormat("Z").format(calendar.getTime());
    return timeZone.substring(0, 3) + ":"+ timeZone.substring(3, 5);
}

returns like +03:30

Answer 5

a one line solution is to use the Z symbol like:

new SimpleDateFormat(pattern, Locale.getDefault()).format(System.currentTimeMillis());

where pattern could be:

• Z/ZZ/ZZZ: -0800
• ZZZZ: GMT-08:00
• ZZZZZ: -08:00

full reference here:

http://developer.android.com/reference/java/text/SimpleDateFormat.html

Answer 6

This is how Google recommends getting TimezoneOffset.

Calendar calendar = Calendar.getInstance(Locale.getDefault());
int offset = -(calendar.get(Calendar.ZONE_OFFSET) + calendar.get(Calendar.DST_OFFSET)) / (60 * 1000)

https://developer.android.com/reference/java/util/Date#getTimezoneOffset()

Answer 7

public static String getCurrentTimezoneOffset() {

    TimeZone tz = TimeZone.getDefault();  
    Calendar cal = GregorianCalendar.getInstance(tz);
    int offsetInMillis = tz.getOffset(cal.getTimeInMillis());

    String offset = String.format("%02d:%02d", Math.abs(offsetInMillis / 3600000), Math.abs((offsetInMillis / 60000) % 60));
    offset = (offsetInMillis >= 0 ? "+" : "-") + offset;

    return offset;
}

Answer 8

 TimeZone tz = TimeZone.getDefault();  
Calendar cal = GregorianCalendar.getInstance(tz);
int offsetInMillis = tz.getOffset(cal.getTimeInMillis());

String offset = String.format("%02d:%02d", Math.abs(offsetInMillis / 3600000), Math.abs((offsetInMillis / 60000) % 60));
offset = (offsetInMillis >= 0 ? "+" : "-") + offset;

Answer 9

Yet another solution to get timezone offset:

TimeZone tz = TimeZone.getDefault();
String current_Time_Zone = getGmtOffsetString(tz.getRawOffset());

public static String getGmtOffsetString(int offsetMillis) {
    int offsetMinutes = offsetMillis / 60000;
    char sign = '+';
    if (offsetMinutes < 0) {
        sign = '-';
        offsetMinutes = -offsetMinutes;
    }
    return String.format("GMT%c%02d:%02d", sign, offsetMinutes/60, offsetMinutes % 60);
}

Answer 10

TimeZone timeZone = TimeZone.getDefault();
String timeZoneInGMTFormat = timeZone.getDisplayName(false,TimeZone.SHORT);

Output : GMT+5:30

Answer 11

If someone is looking how to represent the GMT as a float number representing hour offset
(for example "GMT-0530" to -5.5), you can use this:

Calendar calendar = new GregorianCalendar();
TimeZone timeZone = calendar.getTimeZone();
int offset = timeZone.getRawOffset();
long hours = TimeUnit.MILLISECONDS.toHours(offset);
float minutes = (float)TimeUnit.MILLISECONDS.toMinutes(offset - TimeUnit.HOURS.toMillis(hours)) / MINUTES_IN_HOUR;
float gmt = hours + minutes;

Answer 12

You can do like this:

    TimeZone tz = TimeZone.getDefault();
    int offset = tz.getRawOffset();

    String timeZone = String.format("%s%02d%02d", offset >= 0 ? "+" : "-", offset / 3600000, (offset / 60000) % 60);

Answer 13

Generally you cannot translate from a time zone like Asia/Kolkata to a GMT offset like +05:30 or +07:00. A time zone, as the name says, is a place on earth and comprises the historic, present and known future UTC offsets used by the people in that place (for now we can regard GMT and UTC as synonyms, strictly speaking they are not). For example, Asia/Kolkata has been at offset +05:30 since 1945. During periods between 1941 and 1945 it was at +06:30 and before that time at +05:53:20 (yes, with seconds precision). Many other time zones have summer time (daylight saving time, DST) and change their offset twice a year.

Given a point in time, we can make the translation for that particular point in time, though. I should like to provide the modern way of doing that.

java.time and ThreeTenABP

    ZoneId zone = ZoneId.of("Asia/Kolkata");

    ZoneOffset offsetIn1944 = LocalDateTime.of(1944, Month.JANUARY, 1, 0, 0)
            .atZone(zone)
            .getOffset();
    System.out.println("Offset in 1944: " + offsetIn1944);

    ZoneOffset offsetToday = OffsetDateTime.now(zone)
            .getOffset();
    System.out.println("Offset now: " + offsetToday);

Output when running just now was:

 Offset in 1944: +06:30 Offset now: +05:30

For the default time zone set zone to ZoneId.systemDefault() .

To format the offset with the text GMT use a formatter with OOOO (four uppercase letter O) in the pattern:

    DateTimeFormatter offsetFormatter = DateTimeFormatter.ofPattern("OOOO");
    System.out.println(offsetFormatter.format(offsetToday));

GMT+05:30

I am recommending and in my code I am using java.time, the modern Java date and time API. The TimeZone , Calendar , Date , SimpleDateFormat and DateFormat classes used in many of the other answers are poorly designed and now long outdated, so my suggestion is to avoid all of them.

Question: Can I use java.time on Android?

Yes, java.time works nicely on older and newer Android devices. It just requires at least Java 6 .

• In Java 8 and later and on newer Android devices (from API level 26) the modern API comes built-in.
• In Java 6 and 7 get the ThreeTen Backport, the backport of the modern classes (ThreeTen for JSR 310; see the links at the bottom).
• On (older) Android use the Android edition of ThreeTen Backport. It's called ThreeTenABP. And make sure you import the date and time classes from org.threeten.bp with subpackages.

Links

• Oracle tutorial: Date Time explaining how to use java.time.
• Java Specification Request (JSR) 310 , where java.time was first described.
• ThreeTen Backport project , the backport of java.time to Java 6 and 7 (ThreeTen for JSR-310).
• ThreeTenABP , Android edition of ThreeTen Backport
• Question: How to use ThreeTenABP in Android Project , with a very thorough explanation.

Answer 14

TimeZone tz = TimeZone.getDefault();  
String gmt1=TimeZone.getTimeZone(tz.getID())
      .getDisplayName(false,TimeZone.SHORT);  
String gmt2=TimeZone.getTimeZone(tz.getID())
      .getDisplayName(false,TimeZone.LONG); Log.d("Tag","TimeZone : "+gmt1+"\t"+gmt2);

See if this helps :)

Answer 15

I stumbled upon a simple solution for this in Java8 (non-Android) using the ZoneDateTime class. There may be other classes that implement the TemporalAccessor interface that work, but I haven't found them. This won't work with standard Date , DateTime , LocalDateTime , and Calender classes as far as I can tell.

    ZoneOffset myOffset = ZonedDateTime.now().getOffset();
    ZoneOffset myOffset2 = ZoneOffset.from(ZonedDateTime.now());
    log.info("ZoneOffset is " + myOffset.getId());  // should print "+HH:MM"
    log.info("ZoneOffset2 is " + myOffset2.getId());  // should print "+HH:MM"

The nice thing about this solution is that it avoids a lot of modulo math, string generation, and parsing.

Answer 16

You can get your custom GMT time from this function from here

  public static String getCurrentDate() {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy MM dd hh:mm a zzz");
        Date date = new Date();
        sdf.setTimeZone(TimeZone.getTimeZone("GMT+6:00"));
        return sdf.format(date);
    }

Answer 17

I've been looking at this too and trying to work out how to apply timezone and DST. Here's my code.

    public long applyGMTOffsetDST(long time) {
    // Works out adjustments for timezone and daylight saving time

    Calendar mCalendar = new GregorianCalendar();  
    TimeZone mTimeZone = mCalendar.getTimeZone();  
    boolean dstBool = mTimeZone.getDefault().inDaylightTime( new Date() );
    // add an hour if DST active

    if (dstBool == true) {
        time = time + secondsPerHour;
    }
    // add offest hours
    int mGMTOffset = mTimeZone.getRawOffset();

    if (mGMTOffset > 0) {
        long offsetSeconds = secondsPerHour * mGMTOffset;
        time = time + offsetSeconds;
    }

    return time;
}

This seems to work, but is there a better way to get the actual time off the device which represents a time that is meaningful and accurate to the user?

Answer 18

Adding dst offset will solve this:

    int offsetInMillis = TimeZone.getDefault().getRawOffset()+TimeZone.getDefault().getDSTSavings();
    String offset = String.format("%02d:%02d", Math.abs(offsetInMillis / 3600000), Math.abs((offsetInMillis / 60000) % 60));
    offset = (offsetInMillis >= 0 ? "+" : "-") + offset;
    return offset;

Answer 19

Use this code ( Opt 1 ):

    //Opt 1
    Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("GMT"),
            Locale.getDefault());
    Date currentLocalTime = calendar.getTime();
    DateFormat date = new SimpleDateFormat("Z", Locale.getDefault());
    String localTime = date.format(currentLocalTime);
    String finalTimezone = String.format("GMT%s:%s", localTime.substring(0, 3), localTime.substring(3));
    Log.d(TAG, "timezone 1: " + finalTimezone);

    //Opt 2
    date = new SimpleDateFormat("z",Locale.getDefault());
    localTime = date.format(currentLocalTime);
    Log.d(TAG, "timezone 2: "+localTime);

    //Opt 3
    TimeZone tz = TimeZone.getDefault();
    Log.d(TAG, "timezone 3: "+tz.getDisplayName(true, TimeZone.SHORT));
    //

If I'm in Los Angeles (GTM-07:00 Pacific Standard Time) the output is:

timezone 1: GMT-07:00
timezone 2: PDT
timezone 3: PDT

Answer 20

To get date time with offset like 2019-07-22T13:39:27.397+05:00 Try following Kotlin code:

fun getDateTimeForApiAsString() : String{
    val date = SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSXXX", 
                   Locale.getDefault())
    return date.format(Date())
}

Output Formate:

2019-07-22T13:39:27.397+05:00 //for Pakistan

If you want other similar formats replace pattern in SimpleDateFormat as below:

"yyyy.MM.dd G 'at' HH:mm:ss z"  //Output Format: 2001.07.04 AD at 12:08:56 PDT
"EEE, MMM d, ''yy"  //Output Format:    Wed, Jul 4, '01
"h:mm a"      //Output Format: 12:08 PM
"hh 'o''clock' a, zzzz"   //Output Format:  12 o'clock PM, Pacific Daylight Time
"K:mm a, z"  //Output Format:   0:08 PM, PDT
"yyyyy.MMMMM.dd GGG hh:mm aaa"  //Output Format:    02001.July.04 AD 12:08 PM
"EEE, d MMM yyyy HH:mm:ss Z"  //Output Format:  Wed, 4 Jul 2001 12:08:56 -0700
"yyMMddHHmmssZ"  //Output Format:   010704120856-0700
"yyyy-MM-dd'T'HH:mm:ss.SSSZ"  //Output Format:  2001-07-04T12:08:56.235-0700
"yyyy-MM-dd'T'HH:mm:ss.SSSXXX"  //Output Format:    2001-07-04T12:08:56.235-07:00
"YYYY-'W'ww-u"  //Output Format:    2001-W27-3

Answer 21

I have a correct way：

public static String getCurrentTimeZone() {
    TimeZone timeZone = TimeZone.getDefault();
    return createGmtOffsetString(true, true, timeZone.getRawOffset());
}

public static String createGmtOffsetString(boolean includeGmt,
                                           boolean includeMinuteSeparator, int offsetMillis) {
    int offsetMinutes = offsetMillis / 60000;
    char sign = '+';
    if (offsetMinutes < 0) {
        sign = '-';
        offsetMinutes = -offsetMinutes;
    }
    StringBuilder builder = new StringBuilder(9);
    if (includeGmt) {
        builder.append("GMT");
    }
    builder.append(sign);
    appendNumber(builder, 2, offsetMinutes / 60);
    if (includeMinuteSeparator) {
        builder.append(':');
    }
    appendNumber(builder, 2, offsetMinutes % 60);
    return builder.toString();
}

private static void appendNumber(StringBuilder builder, int count, int value) {
    String string = Integer.toString(value);
    for (int i = 0; i < count - string.length(); i++) {
        builder.append('0');
    }
    builder.append(string);
}

Answer 22

You can get the time zone offset formatted like +01:00 with following but two

1. For API level 24+ then use XXX
2. For API level 24 or lower use ZZZZZ

To get result like this: 2011-12-03T10:15:30+01:00

you have to do:

For Api level 24+ use " yyyy-MM-dd'T'HH:mm:ss.SSSXXX "

For Api level below 24 use " yyyy-MM-dd'T'HH:mm:ss.SSSZZZZZ "

Answer 23

The best solution that i found for myself

SimpleDateFormat("XXX", Locale.getDefault()).format(System.currentTimeMillis())

+03:00

You can try to change pattern (the "xxx" string) to get the result you want, for example:

SimpleDateFormat("XX", Locale.getDefault()).format(System.currentTimeMillis())

+0300

SimpleDateFormat("X", Locale.getDefault()).format(System.currentTimeMillis())

+03

Pattern can also apply another letters and the result will be different

SimpleDateFormat("Z", Locale.getDefault()).format(System.currentTimeMillis())

+0300

More about this you can find here: https://developer.android.com/reference/java/text/SimpleDateFormat.html

Answer 24

TimeZone timeZone = TimeZone.getTimeZone("GMT+7:00");

declare it explicitely.