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java.lang.Objectcom.trolltech.qt.internal.QSignalEmitterInternal
com.trolltech.qt.QSignalEmitter
com.trolltech.qt.QtJambiObject
com.trolltech.qt.core.QDate
public class QDate
The QDate class provides date functions. A QDate object contains a calendar date, i.e. year, month, and day numbers, in the Gregorian calendar. (see Use of Gregorian and Julian Calendars for dates prior to 15 October 1582). It can read the current date from the system clock. It provides functions for comparing dates, and for manipulating dates. For example, it is possible to add and subtract days, months, and years to dates.
A QDate object is typically created either by giving the year, month, and day numbers explicitly. Note that QDate interprets two digit years to be in the 1900s, e.g., 50 will equals 1950. A QDate can also be constructed with the static function currentDate()
, which creates a QDate object containing the system clock's date. An explicit date can also be set using setDate()
. The fromString()
function returns a QDate given a string and a date format which is used to interpret the date within the string.
The year()
, month()
, and day()
functions provide access to the year, month, and day numbers. Also, dayOfWeek()
and dayOfYear()
functions are provided. The same information is provided in textual format by the toString()
, shortDayName()
, longDayName()
, shortMonthName()
, and longMonthName()
functions.
QDate provides a full set of operators to compare two QDate objects where smaller means earlier, and larger means later.
You can increment (or decrement) a date by a given number of days using addDays()
. Similarly you can use addMonths()
and addYears()
. The daysTo()
function returns the number of days between two dates.
The daysInMonth()
and daysInYear()
functions return how many days there are in this date's month and year, respectively. The isLeapYear()
function indicates whether a date is in a leap year.Use of Gregorian and Julian Calendars
QDate uses the Gregorian calendar in all locales, beginning on the date 15 October 1582. For dates up to and including 4 October 1582, the Julian calendar is used. This means there is a 10-day gap in the internal calendar between the 4th and the 15th of October 1582. When you use QDateTime
for dates in that epoch, the day after 4 October 1582 is 15 October 1582, and the dates in the gap are invalid.
The Julian to Gregorian changeover date used here is the date when the Gregorian calendar was first introduced, by Pope Gregory XIII. That change was not universally accepted and some localities only executed it at a later date (if at all). QDateTime
doesn't take any of these historical facts into account. If an application must support a locale-specific dating system, it must do so on its own, remembering to convert the dates using the Julian day.No Year 0
There is no year 0. Dates in that year are considered invalid. The year -1 is the year "1 before Christ" or "1 before current era." The day before 0001-01-01 is December 31st, 1 BCE.Range of Valid Dates
The range of valid dates is from January 2nd, 4713 BCE, to sometime in the year 11 million CE. The Julian Day returned by QDate::toJulianDay()
is a number in the contiguous range from 1 to overflow, even across QDateTime
's "date holes". It is suitable for use in applications that must convert a QDateTime
to a date in another calendar system, e.g., Hebrew, Islamic or Chinese.
QTime
, QDateTime
, QDateEdit
, QDateTimeEdit
, and QCalendarWidget
.
Nested Class Summary |
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Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter |
---|
QSignalEmitter.AbstractSignal, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9 |
Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal |
---|
com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal |
Field Summary |
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Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal |
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currentSender |
Constructor Summary | |
---|---|
QDate()
Constructs a null date. |
|
QDate(int y,
int m,
int d)
Constructs a date with year y, month m and day d. |
Method Summary | |
---|---|
QDate |
addDays(int days)
Returns a QDate object containing a date ndays later than the date of this object (or earlier if ndays is negative). |
QDate |
addMonths(int months)
Returns a QDate object containing a date nmonths later than the date of this object (or earlier if nmonths is negative). |
QDate |
addYears(int years)
Returns a QDate object containing a date nyears later than the date of this object (or earlier if nyears is negative). |
QDate |
clone()
This method is reimplemented for internal reasons |
static QDate |
currentDate()
Returns the current date, as reported by the system clock. |
int |
day()
Returns the day of the month (1 to 31) of this date. |
int |
dayOfWeek()
Returns the weekday (1 to 7) for this date. |
int |
dayOfYear()
Returns the day of the year (1 to 365 or 366 on leap years) for this date. |
int |
daysInMonth()
Returns the number of days in the month (28 to 31) for this date. |
int |
daysInYear()
Returns the number of days in the year (365 or 366) for this date. |
int |
daysTo(QDate arg__1)
Returns the number of days from this date to d (which is negative if d is earlier than this date). |
static QDate |
fromJulianDay(int jd)
Converts the Julian day jd to a QDate. |
static QDate |
fromString(java.lang.String s)
Returns the QDate represented by the string, using the format given, or an invalid date if the string cannot be parsed. |
static QDate |
fromString(java.lang.String s,
Qt.DateFormat f)
Returns the QDate represented by the string, using the format given, or an invalid date if the string cannot be parsed. |
static QDate |
fromString(java.lang.String s,
java.lang.String format)
Returns the QDate represented by the string, using the format given, or an invalid date if the string cannot be parsed. |
static boolean |
isLeapYear(int year)
Returns true if the specified year is a leap year; otherwise returns false. |
boolean |
isNull()
Returns true if the date is null; otherwise returns false. |
boolean |
isValid()
Returns true if this date is valid; otherwise returns false. |
static boolean |
isValid(int y,
int m,
int d)
Returns true if the specified date (year, month, and day) is valid; otherwise returns false. |
static java.lang.String |
longDayName(int weekday)
Returns the long name of the weekday using the following convention. |
static java.lang.String |
longMonthName(int month)
Returns the long name of the month using the following convention. |
int |
month()
Returns the number corresponding to the month of this date, using the following convention. |
void |
readFrom(QDataStream arg__1)
|
boolean |
setDate(int year,
int month,
int date)
Sets the date's year, month, and day. |
static java.lang.String |
shortDayName(int weekday)
Returns the name of the weekday using the following convention. |
static java.lang.String |
shortMonthName(int month)
Returns the name of the month using the following convention. |
int |
toJulianDay()
Converts the date to a Julian day. |
java.lang.String |
toString()
|
java.lang.String |
toString(Qt.DateFormat f)
|
java.lang.String |
toString(java.lang.String format)
|
int |
weekNumber()
Returns the week number (1 to 53). |
void |
writeTo(QDataStream arg__1)
|
int |
year()
Returns the year of this date. |
int |
yearOfWeekNumber()
This function returns the year number of the QDate's current week. |
Methods inherited from class com.trolltech.qt.QtJambiObject |
---|
dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr |
Methods inherited from class com.trolltech.qt.QSignalEmitter |
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blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread |
Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal |
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__qt_signalInitialization |
Methods inherited from class java.lang.Object |
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getClass, hashCode, notify, notifyAll, wait, wait, wait |
Methods inherited from interface java.lang.Comparable |
---|
compareTo |
Methods inherited from interface com.trolltech.qt.QtJambiInterface |
---|
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership |
Constructor Detail |
---|
public QDate()
isNull()
, and isValid()
.
public QDate(int y, int m, int d)
If the specified date is invalid, the date is not set and isValid()
returns false. A date before 2 January 4713 B.C. is considered invalid.
Warning: Years 1 to 99 are interpreted as being in the 1900s. If you want to specify the year 2010, you must write 2010, not 10.
isValid()
.
Method Detail |
---|
public final QDate addDays(int days)
addMonths()
, addYears()
, and daysTo()
.
public final QDate addMonths(int months)
addDays()
, and addYears()
.
public final QDate addYears(int years)
addDays()
, and addMonths()
.
public final int day()
year()
, month()
, and dayOfWeek()
.
public final int dayOfWeek()
day()
, dayOfYear()
, and Qt::DayOfWeek
.
public final int dayOfYear()
day()
, and dayOfWeek()
.
public final int daysInMonth()
day()
, and daysInYear()
.
public final int daysInYear()
day()
, and daysInMonth()
.
public final int daysTo(QDate arg__1)
Example:
QDate d1 = new QDate(1995, 5, 17); // May 17, 1995 QDate d2 = new QDate(1995, 5, 20); // May 20, 1995 d1.daysTo(d2); // returns 3 d2.daysTo(d1); // returns -3
addDays()
.
public final boolean isNull()
Note: The behavior of this function is identical to isValid()
.
isValid()
.
public final boolean isValid()
isNull()
.
public final int month()
year()
, and day()
.
public final void writeTo(QDataStream arg__1)
public final void readFrom(QDataStream arg__1)
public final boolean setDate(int year, int month, int date)
If the specified date is invalid, the QDate object is set to be invalid. Any date before 2 January 4713 B.C. is considered invalid.
isValid()
.
public final int toJulianDay()
fromJulianDay()
.
public final java.lang.String toString()
toString
in class java.lang.Object
public final java.lang.String toString(Qt.DateFormat f)
public final java.lang.String toString(java.lang.String format)
public final int year()
month()
, and day()
.
public static QDate currentDate()
QTime::currentTime()
, and QDateTime::currentDateTime()
.
public static QDate fromJulianDay(int jd)
toJulianDay()
.
public static QDate fromString(java.lang.String s)
Note that years specified with two digits are interpreted to be between 1900 and 1999.
Note for Qt::TextDate
: It is recommended that you use the English short month names (e.g. "Jan"). Although localized month names can also be used, they depend on the user's locale settings.
public static QDate fromString(java.lang.String s, Qt.DateFormat f)
Note that years specified with two digits are interpreted to be between 1900 and 1999.
Note for Qt::TextDate
: It is recommended that you use the English short month names (e.g. "Jan"). Although localized month names can also be used, they depend on the user's locale settings.
public static QDate fromString(java.lang.String s, java.lang.String format)
These expressions may be used for the format:
d | The day as a number without a leading zero (1 to 31) |
dd | The day as a number with a leading zero (01 to 31) |
ddd | The abbreviated localized day name (e.g. 'Mon' to 'Sun'). Uses QDate::shortDayName() . |
dddd | The long localized day name (e.g. 'Monday' to 'Sunday'). Uses QDate::longDayName() . |
M | The month as a number without a leading zero (1 to 12) |
MM | The month as a number with a leading zero (01 to 12) |
MMM | The abbreviated localized month name (e.g. 'Jan' to 'Dec'). Uses QDate::shortMonthName() . |
MMMM | The long localized month name (e.g. 'January' to 'December'). Uses QDate::longMonthName() . |
yy | The year as two digit number (00 to 99) |
yyyy | The year as four digit number. If the year is negative, a minus sign is prepended in addition. |
QDate date = QDate.fromString("1MM12car2003", "d'MM'MMcaryyyy"); // date is 1 December 2003If the format is not satisfied, an invalid QDate is returned. The expressions that don't expect leading zeroes (d, M) will be greedy. This means that they will use two digits even if this will put them outside the accepted range of values and leaves too few digits for other sections. For example, the following format string could have meant January 30 but the M will grab two digits, resulting in an invalid date:
QDate date = QDate.fromString("130", "Md"); // invalidFor any field that is not represented in the format the following defaults are used:
Year | 1900 |
Month | 1 |
Day | 1 |
QDate.fromString("1.30", "M.d"); // January 30 1900 QDate.fromString("20000110", "yyyyMMdd"); // January 10, 2000 QDate.fromString("20000110", "yyyyMd"); // January 10, 2000
QDateTime::fromString()
, QTime::fromString()
, QDate::toString()
, QDateTime::toString()
, and QTime::toString()
.
public static boolean isLeapYear(int year)
public static boolean isValid(int y, int m, int d)
Example:
QDate.isValid(2002, 5, 17); // true QDate.isValid(2002, 2, 30); // false (Feb 30 does not exist) QDate.isValid(2004, 2, 29); // true (2004 is a leap year) QDate.isValid(2000, 2, 29); // true (2000 is a leap year) QDate.isValid(2006, 2, 29); // false (2006 is not a leap year) QDate.isValid(2100, 2, 29); // false (2100 is not a leap year) QDate.isValid(1202, 6, 6); // true (even though 1202 is pre-Gregorian)
isNull()
, and setDate()
.
public static java.lang.String longDayName(int weekday)
toString()
, shortDayName()
, shortMonthName()
, and longMonthName()
.
public static java.lang.String longMonthName(int month)
toString()
, shortMonthName()
, shortDayName()
, and longDayName()
.
public static java.lang.String shortDayName(int weekday)
toString()
, shortMonthName()
, longMonthName()
, and longDayName()
.
public static java.lang.String shortMonthName(int month)
toString()
, longMonthName()
, shortDayName()
, and longDayName()
.
public final int weekNumber()
Returns null if the date is invalid.
In accordance with ISO 8601, weeks start on Qt.DayOfWeek.Monday and the first Qt.DayOfWeek.Thursday of a year is always in week 1 of that year. Most years have 52 weeks, but some have 53.
Copyright (c) 1989 The Regents of the University of California. All rights reserved.
Redistribution and use in source and binary forms are permitted provided that the above copyright notice and this paragraph are duplicated in all such forms and that any documentation, advertising materials, and other materials related to such distribution and use acknowledge that the software was developed by the University of California, Berkeley. The name of the University may not be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
public final int yearOfWeekNumber()
public QDate clone()
clone
in class java.lang.Object
|
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