GregorianCalendar Class

Definition

[Android.Runtime.Register("java/util/GregorianCalendar", DoNotGenerateAcw=true)]
public class GregorianCalendar : Java.Util.Calendar

[<Android.Runtime.Register("java/util/GregorianCalendar", DoNotGenerateAcw=true)>]
type GregorianCalendar = class
    inherit Calendar

Inheritance

Object

Object

Calendar

GregorianCalendar

Attributes

RegisterAttribute

Remarks

GregorianCalendar is a concrete subclass of Calendar and provides the standard calendar system used by most of the world.

GregorianCalendar is a hybrid calendar that supports both the Julian and Gregorian calendar systems with the support of a single discontinuity, which corresponds by default to the Gregorian date when the Gregorian calendar was instituted (October 15, 1582 in some countries, later in others). The cutover date may be changed by the caller by calling #setGregorianChange(Date) setGregorianChange().

Historically, in those countries which adopted the Gregorian calendar first, October 4, 1582 (Julian) was thus followed by October 15, 1582 (Gregorian). This calendar models this correctly. Before the Gregorian cutover, GregorianCalendar implements the Julian calendar. The only difference between the Gregorian and the Julian calendar is the leap year rule. The Julian calendar specifies leap years every four years, whereas the Gregorian calendar omits century years which are not divisible by 400.

GregorianCalendar implements <em>proleptic</em> Gregorian and Julian calendars. That is, dates are computed by extrapolating the current rules indefinitely far backward and forward in time. As a result, GregorianCalendar may be used for all years to generate meaningful and consistent results. However, dates obtained using GregorianCalendar are historically accurate only from March 1, 4 AD onward, when modern Julian calendar rules were adopted. Before this date, leap year rules were applied irregularly, and before 45 BC the Julian calendar did not even exist.

Prior to the institution of the Gregorian calendar, New Year's Day was March 25. To avoid confusion, this calendar always uses January 1. A manual adjustment may be made if desired for dates that are prior to the Gregorian changeover and which fall between January 1 and March 24.

<h3>"week_and_year">Week Of Year and Week Year</h3>

Values calculated for the Calendar#WEEK_OF_YEAR WEEK_OF_YEAR field range from 1 to 53. The first week of a calendar year is the earliest seven day period starting on Calendar#getFirstDayOfWeek() getFirstDayOfWeek() that contains at least Calendar#getMinimalDaysInFirstWeek() getMinimalDaysInFirstWeek() days from that year. It thus depends on the values of getMinimalDaysInFirstWeek(), getFirstDayOfWeek(), and the day of the week of January 1. Weeks between week 1 of one year and week 1 of the following year (exclusive) are numbered sequentially from 2 to 52 or 53 (except for year(s) involved in the Julian-Gregorian transition).

The getFirstDayOfWeek() and getMinimalDaysInFirstWeek() values are initialized using locale-dependent resources when constructing a GregorianCalendar. "iso8601_compatible_setting">The week determination is compatible with the ISO 8601 standard when getFirstDayOfWeek() is MONDAY and getMinimalDaysInFirstWeek() is 4, which values are used in locales where the standard is preferred. These values can explicitly be set by calling Calendar#setFirstDayOfWeek(int) setFirstDayOfWeek() and Calendar#setMinimalDaysInFirstWeek(int) setMinimalDaysInFirstWeek().

A "week_year"><em>week year</em> is in sync with a WEEK_OF_YEAR cycle. All weeks between the first and last weeks (inclusive) have the same <em>week year</em> value. Therefore, the first and last days of a week year may have different calendar year values.

For example, January 1, 1998 is a Thursday. If getFirstDayOfWeek() is MONDAY and getMinimalDaysInFirstWeek() is 4 (ISO 8601 standard compatible setting), then week 1 of 1998 starts on December 29, 1997, and ends on January 4, 1998. The week year is 1998 for the last three days of calendar year 1997. If, however, getFirstDayOfWeek() is SUNDAY, then week 1 of 1998 starts on January 4, 1998, and ends on January 10, 1998; the first three days of 1998 then are part of week 53 of 1997 and their week year is 1997.

<h4>Week Of Month</h4>

Values calculated for the WEEK_OF_MONTH field range from 0 to 6. Week 1 of a month (the days with WEEK_OF_MONTH = 1) is the earliest set of at least getMinimalDaysInFirstWeek() contiguous days in that month, ending on the day before getFirstDayOfWeek(). Unlike week 1 of a year, week 1 of a month may be shorter than 7 days, need not start on getFirstDayOfWeek(), and will not include days of the previous month. Days of a month before week 1 have a WEEK_OF_MONTH of 0.

For example, if getFirstDayOfWeek() is SUNDAY and getMinimalDaysInFirstWeek() is 4, then the first week of January 1998 is Sunday, January 4 through Saturday, January 10. These days have a WEEK_OF_MONTH of 1. Thursday, January 1 through Saturday, January 3 have a WEEK_OF_MONTH of 0. If getMinimalDaysInFirstWeek() is changed to 3, then January 1 through January 3 have a WEEK_OF_MONTH of 1.

<h4>Default Fields Values</h4>

The clear method sets calendar field(s) undefined. GregorianCalendar uses the following default value for each calendar field if its value is undefined.

<table class="striped" style="text-align: left; width: 66%;"> <caption style="display:none">GregorianCalendar default field values</caption> <thead> <tr> <th scope="col"> Field </th> <th scope="col"> Default Value </th> </tr> </thead> <tbody> <tr> <th scope="row"> ERA</th> <td> AD</td> </tr> <tr> <th scope="row"> YEAR</th> <td> 1970</td> </tr> <tr> <th scope="row"> MONTH</th> <td> JANUARY</td> </tr> <tr> <th scope="row"> DAY_OF_MONTH</th> <td> 1</td> </tr> <tr> <th scope="row"> DAY_OF_WEEK</th> <td> the first day of week</td> </tr> <tr> <th scope="row"> WEEK_OF_MONTH</th> <td> 0</td> </tr> <tr> <th scope="row"> DAY_OF_WEEK_IN_MONTH</th> <td> 1</td> </tr> <tr> <th scope="row"> AM_PM</th> <td> AM</td> </tr> <tr> <th scope="row"> HOUR, HOUR_OF_DAY, MINUTE, SECOND, MILLISECOND</th> <td> 0</td> </tr> </tbody> </table> <br>Default values are not applicable for the fields not listed above.

<strong>Example:</strong> <blockquote>

// get the supported ids for GMT-08:00 (Pacific Standard Time)
            String[] ids = TimeZone.getAvailableIDs(-8 * 60 * 60 * 1000);
            // if no ids were returned, something is wrong. get out.
            if (ids.length == 0)
                System.exit(0);

             // begin output
            System.out.println("Current Time");

            // create a Pacific Standard Time time zone
            SimpleTimeZone pdt = new SimpleTimeZone(-8 * 60 * 60 * 1000, ids[0]);

            // set up rules for Daylight Saving Time
            pdt.setStartRule(Calendar.APRIL, 1, Calendar.SUNDAY, 2 * 60 * 60 * 1000);
            pdt.setEndRule(Calendar.OCTOBER, -1, Calendar.SUNDAY, 2 * 60 * 60 * 1000);

            // create a GregorianCalendar with the Pacific Daylight time zone
            // and the current date and time
            Calendar calendar = new GregorianCalendar(pdt);
            Date trialTime = new Date();
            calendar.setTime(trialTime);

            // print out a bunch of interesting things
            System.out.println("ERA: " + calendar.get(Calendar.ERA));
            System.out.println("YEAR: " + calendar.get(Calendar.YEAR));
            System.out.println("MONTH: " + calendar.get(Calendar.MONTH));
            System.out.println("WEEK_OF_YEAR: " + calendar.get(Calendar.WEEK_OF_YEAR));
            System.out.println("WEEK_OF_MONTH: " + calendar.get(Calendar.WEEK_OF_MONTH));
            System.out.println("DATE: " + calendar.get(Calendar.DATE));
            System.out.println("DAY_OF_MONTH: " + calendar.get(Calendar.DAY_OF_MONTH));
            System.out.println("DAY_OF_YEAR: " + calendar.get(Calendar.DAY_OF_YEAR));
            System.out.println("DAY_OF_WEEK: " + calendar.get(Calendar.DAY_OF_WEEK));
            System.out.println("DAY_OF_WEEK_IN_MONTH: "
                               + calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH));
            System.out.println("AM_PM: " + calendar.get(Calendar.AM_PM));
            System.out.println("HOUR: " + calendar.get(Calendar.HOUR));
            System.out.println("HOUR_OF_DAY: " + calendar.get(Calendar.HOUR_OF_DAY));
            System.out.println("MINUTE: " + calendar.get(Calendar.MINUTE));
            System.out.println("SECOND: " + calendar.get(Calendar.SECOND));
            System.out.println("MILLISECOND: " + calendar.get(Calendar.MILLISECOND));
            System.out.println("ZONE_OFFSET: "
                               + (calendar.get(Calendar.ZONE_OFFSET)/(60*60*1000)));
            System.out.println("DST_OFFSET: "
                               + (calendar.get(Calendar.DST_OFFSET)/(60*60*1000)));

            System.out.println("Current Time, with hour reset to 3");
            calendar.clear(Calendar.HOUR_OF_DAY); // so doesn't override
            calendar.set(Calendar.HOUR, 3);
            System.out.println("ERA: " + calendar.get(Calendar.ERA));
            System.out.println("YEAR: " + calendar.get(Calendar.YEAR));
            System.out.println("MONTH: " + calendar.get(Calendar.MONTH));
            System.out.println("WEEK_OF_YEAR: " + calendar.get(Calendar.WEEK_OF_YEAR));
            System.out.println("WEEK_OF_MONTH: " + calendar.get(Calendar.WEEK_OF_MONTH));
            System.out.println("DATE: " + calendar.get(Calendar.DATE));
            System.out.println("DAY_OF_MONTH: " + calendar.get(Calendar.DAY_OF_MONTH));
            System.out.println("DAY_OF_YEAR: " + calendar.get(Calendar.DAY_OF_YEAR));
            System.out.println("DAY_OF_WEEK: " + calendar.get(Calendar.DAY_OF_WEEK));
            System.out.println("DAY_OF_WEEK_IN_MONTH: "
                               + calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH));
            System.out.println("AM_PM: " + calendar.get(Calendar.AM_PM));
            System.out.println("HOUR: " + calendar.get(Calendar.HOUR));
            System.out.println("HOUR_OF_DAY: " + calendar.get(Calendar.HOUR_OF_DAY));
            System.out.println("MINUTE: " + calendar.get(Calendar.MINUTE));
            System.out.println("SECOND: " + calendar.get(Calendar.SECOND));
            System.out.println("MILLISECOND: " + calendar.get(Calendar.MILLISECOND));
            System.out.println("ZONE_OFFSET: "
                   + (calendar.get(Calendar.ZONE_OFFSET)/(60*60*1000))); // in hours
            System.out.println("DST_OFFSET: "
                   + (calendar.get(Calendar.DST_OFFSET)/(60*60*1000))); // in hours

</blockquote>

Added in 1.1.

Java documentation for java.util.GregorianCalendar.

Portions of this page are modifications based on work created and shared by the Android Open Source Project and used according to terms described in the Creative Commons 2.5 Attribution License.

Constructors

Fields

Properties

Methods

Explicit Interface Implementations

Extension Methods

Applies to