Time
public
class
Time
extends Object
java.lang.Object | |
↳ | android.text.format.Time |
This class was deprecated
in API level 22.
Use GregorianCalendar
instead.
An alternative to the Calendar
and
GregorianCalendar
classes. An instance of the Time class represents
a moment in time, specified with second precision. It is modelled after
struct tm. This class is not thread-safe and does not consider leap seconds.
This class has a number of issues and it is recommended that
GregorianCalendar
is used instead.
Known issues:
- For historical reasons when performing time calculations all arithmetic currently takes place using 32-bit integers. This limits the reliable time range representable from 1902 until 2037.See the wikipedia article on the Year 2038 problem for details. Do not rely on this behavior; it may change in the future.
- Calling
switchTimezone(java.lang.String)
on a date that cannot exist, such as a wall time that was skipped due to a DST transition, will result in a date in 1969 (i.e. -1, or 1 second before 1st Jan 1970 UTC). - Much of the formatting / parsing assumes ASCII text and is therefore not suitable for use with non-ASCII scripts.
- No support for pseudo-zones like "GMT-07:00".
Summary
Constants | |
---|---|
int |
EPOCH_JULIAN_DAY
The Julian day of the epoch, that is, January 1, 1970 on the Gregorian calendar. |
int |
FRIDAY
|
int |
HOUR
|
int |
MINUTE
|
int |
MONDAY
|
int |
MONDAY_BEFORE_JULIAN_EPOCH
The Julian day of the Monday in the week of the epoch, December 29, 1969 on the Gregorian calendar. |
int |
MONTH
|
int |
MONTH_DAY
|
int |
SATURDAY
|
int |
SECOND
|
int |
SUNDAY
|
int |
THURSDAY
|
String |
TIMEZONE_UTC
|
int |
TUESDAY
|
int |
WEDNESDAY
|
int |
WEEK_DAY
|
int |
WEEK_NUM
|
int |
YEAR
|
int |
YEAR_DAY
|
Fields | |
---|---|
public
boolean |
allDay
True if this is an allDay event. |
public
long |
gmtoff
Offset in seconds from UTC including any DST offset. |
public
int |
hour
Hour of day [0-23] |
public
int |
isDst
This time is in daylight savings time. |
public
int |
minute
Minute [0-59] |
public
int |
month
Month [0-11] |
public
int |
monthDay
Day of month [1-31] |
public
int |
second
Seconds [0-61] (2 leap seconds allowed) |
public
String |
timezone
The timezone for this Time. |
public
int |
weekDay
Day of week [0-6] |
public
int |
year
Year. |
public
int |
yearDay
Day of year [0-365] |
Public constructors | |
---|---|
Time(String timezoneId)
Construct a Time object in the timezone named by the string argument "timezone". |
|
Time()
Construct a Time object in the default timezone. |
|
Time(Time other)
A copy constructor. |
Public methods | |
---|---|
boolean
|
after(Time that)
Returns true if the time represented by this Time object occurs after the given time. |
boolean
|
before(Time that)
Returns true if the time represented by this Time object occurs before the given time. |
void
|
clear(String timezoneId)
Clears all values, setting the timezone to the given timezone. |
static
int
|
compare(Time a, Time b)
Compare two |
String
|
format(String format)
Print the current value given the format string provided. |
String
|
format2445()
Format according to RFC 2445 DATE-TIME type. |
String
|
format3339(boolean allDay)
Return a string in the RFC 3339 format. |
int
|
getActualMaximum(int field)
Return the maximum possible value for the given field given the value of the other fields. |
static
String
|
getCurrentTimezone()
Returns the timezone string that is currently set for the device. |
static
int
|
getJulianDay(long millis, long gmtoffSeconds)
This method is deprecated.
Use |
static
int
|
getJulianMondayFromWeeksSinceEpoch(int week)
Takes a number of weeks since the epoch and calculates the Julian day of the Monday for that week. |
int
|
getWeekNumber()
Computes the week number according to ISO 8601. |
static
int
|
getWeeksSinceEpochFromJulianDay(int julianDay, int firstDayOfWeek)
Returns the week since |
static
boolean
|
isEpoch(Time time)
Returns true if the instant of the supplied time would be for the Gregorian calendar date January 1, 1970 for a user observing UTC , i.e. |
long
|
normalize(boolean ignoreDst)
Ensures the values in each field are in range. |
boolean
|
parse(String s)
Parses a date-time string in either the RFC 2445 format or an abbreviated format that does not include the "time" field. |
boolean
|
parse3339(String s)
Parse a time in RFC 3339 format. |
void
|
set(Time that)
Copy the value of that to this Time object. |
void
|
set(int second, int minute, int hour, int monthDay, int month, int year)
Sets the fields. |
void
|
set(int monthDay, int month, int year)
Sets the date from the given fields. |
void
|
set(long millis)
Sets the fields in this Time object given the UTC milliseconds. |
long
|
setJulianDay(int julianDay)
Sets the time from the given Julian day number, which must be based on the same timezone that is set in this Time object. |
void
|
setToNow()
Sets the time of the given Time object to the current time. |
void
|
switchTimezone(String timezone)
Convert this time object so the time represented remains the same, but is instead located in a different timezone. |
long
|
toMillis(boolean ignoreDst)
Converts this time to milliseconds. |
String
|
toString()
Return the current time in YYYYMMDDTHHMMSS<tz> format |
Inherited methods | |
---|---|
Constants
EPOCH_JULIAN_DAY
public static final int EPOCH_JULIAN_DAY
The Julian day of the epoch, that is, January 1, 1970 on the Gregorian calendar.
Constant Value: 2440588 (0x00253d8c)
MONDAY_BEFORE_JULIAN_EPOCH
public static final int MONDAY_BEFORE_JULIAN_EPOCH
The Julian day of the Monday in the week of the epoch, December 29, 1969 on the Gregorian calendar.
Constant Value: 2440585 (0x00253d89)
Fields
allDay
public boolean allDay
True if this is an allDay event. The hour, minute, second fields are all zero, and the date is displayed the same in all time zones.
isDst
public int isDst
This time is in daylight savings time. One of:
- positive - in dst
- 0 - not in dst
- negative - unknown
timezone
public String timezone
The timezone for this Time. Should not be null.
Public constructors
Time
public Time (String timezoneId)
Construct a Time object in the timezone named by the string argument "timezone". The time is initialized to Jan 1, 1970.
Parameters | |
---|---|
timezoneId |
String : string containing the timezone to use. |
See also:
Time
public Time ()
Construct a Time object in the default timezone. The time is initialized to Jan 1, 1970.
Time
public Time (Time other)
A copy constructor. Construct a Time object by copying the given Time object. No normalization occurs.
Public methods
after
public boolean after (Time that)
Returns true if the time represented by this Time object occurs after the given time.
Equivalent to Time.compare(this, that) > 0
. See
compare(android.text.format.Time, android.text.format.Time)
for details.
Parameters | |
---|---|
that |
Time : a given Time object to compare against |
Returns | |
---|---|
boolean |
true if this time is greater than the given time |
before
public boolean before (Time that)
Returns true if the time represented by this Time object occurs before the given time.
Equivalent to Time.compare(this, that) < 0
. See
compare(android.text.format.Time, android.text.format.Time)
for details.
Parameters | |
---|---|
that |
Time : a given Time object to compare against |
Returns | |
---|---|
boolean |
true if this time is less than the given time |
clear
public void clear (String timezoneId)
Clears all values, setting the timezone to the given timezone. Sets isDst to a negative value to mean "unknown".
Parameters | |
---|---|
timezoneId |
String : the timezone to use. |
compare
public static int compare (Time a, Time b)
Compare two Time
objects and return a negative number if a
is less than b
, a positive number if a
is greater than
b
, or 0 if they are equal.
This method can return an incorrect answer when the date / time fields of
either Time
have been set to a local time that contradicts the
available timezone information.
Parameters | |
---|---|
a |
Time : first Time instance to compare |
b |
Time : second Time instance to compare |
Returns | |
---|---|
int |
a negative result if a is earlier, a positive result if
b is earlier, or 0 if they are equal. |
Throws | |
---|---|
NullPointerException |
if either argument is null |
IllegalArgumentException |
if allDay is true but hour , minute , and second are not 0. |
format
public String format (String format)
Print the current value given the format string provided. See strftime(3) manual page for what means what. The final string must be less than 256 characters.
Parameters | |
---|---|
format |
String : a string containing the desired format. |
Returns | |
---|---|
String |
a String containing the current time expressed in the current locale. |
format2445
public String format2445 ()
Format according to RFC 2445 DATE-TIME type.
The same as format("%Y%m%dT%H%M%S"), or format("%Y%m%dT%H%M%SZ") for a Time with a timezone set to "UTC".
Returns | |
---|---|
String |
format3339
public String format3339 (boolean allDay)
Return a string in the RFC 3339 format.
If allDay is true, expresses the time as Y-M-D
Otherwise, if the timezone is UTC, expresses the time as Y-M-D-T-H-M-S UTC
Otherwise the time is expressed the time as Y-M-D-T-H-M-S +- GMT
Parameters | |
---|---|
allDay |
boolean |
Returns | |
---|---|
String |
string in the RFC 3339 format. |
getActualMaximum
public int getActualMaximum (int field)
Return the maximum possible value for the given field given the value of the other fields. Requires that it be normalized for MONTH_DAY and YEAR_DAY.
Parameters | |
---|---|
field |
int : one of the constants for HOUR, MINUTE, SECOND, etc. |
Returns | |
---|---|
int |
the maximum value for the field. |
getCurrentTimezone
public static String getCurrentTimezone ()
Returns the timezone string that is currently set for the device.
Returns | |
---|---|
String |
getJulianDay
public static int getJulianDay (long millis, long gmtoffSeconds)
This method is deprecated.
Use JulianFields.JULIAN_DAY
instead.
Computes the Julian day number for a point in time in a particular timezone. The Julian day for a given calendar date is the same for every timezone. For example, the Julian day for July 1, 2008 is 2454649.
Callers must pass the time in UTC millisecond (as can be returned
by toMillis(boolean)
or normalize(boolean)
)
and the offset from UTC of the timezone in seconds at that time (as
might be in gmtoff
).
The Julian day is useful for testing if two events occur on the same calendar date and for determining the relative time of an event from the present ("yesterday", "3 days ago", etc.).
Parameters | |
---|---|
millis |
long : the time in UTC milliseconds |
gmtoffSeconds |
long : the offset from UTC in seconds |
Returns | |
---|---|
int |
the Julian day |
getJulianMondayFromWeeksSinceEpoch
public static int getJulianMondayFromWeeksSinceEpoch (int week)
Takes a number of weeks since the epoch and calculates the Julian day of
the Monday for that week. This assumes that the week containing the
EPOCH_JULIAN_DAY
is considered week 0. It returns the Julian day
for the Monday week weeks after the Monday of the week containing the
epoch.
Parameters | |
---|---|
week |
int : Number of weeks since the epoch |
Returns | |
---|---|
int |
The julian day for the Monday of the given week since the epoch |
getWeekNumber
public int getWeekNumber ()
Computes the week number according to ISO 8601. The current Time object must already be normalized because this method uses the yearDay and weekDay fields.
In IS0 8601, weeks start on Monday. The first week of the year (week 1) is defined by ISO 8601 as the first week with four or more of its days in the starting year. Or equivalently, the week containing January 4. Or equivalently, the week with the year's first Thursday in it.
The week number can be calculated by counting Thursdays. Week N contains the Nth Thursday of the year.
Returns | |
---|---|
int |
the ISO week number. |
getWeeksSinceEpochFromJulianDay
public static int getWeeksSinceEpochFromJulianDay (int julianDay, int firstDayOfWeek)
Returns the week since EPOCH_JULIAN_DAY
(Jan 1, 1970) adjusted
for first day of week. This takes a julian day and the week start day and
calculates which week since EPOCH_JULIAN_DAY
that day occurs in,
starting at 0. *Do not* use this to compute the ISO week number for the
year.
Parameters | |
---|---|
julianDay |
int : The julian day to calculate the week number for |
firstDayOfWeek |
int : Which week day is the first day of the week, see
SUNDAY |
Returns | |
---|---|
int |
Weeks since the epoch |
isEpoch
public static boolean isEpoch (Time time)
Returns true if the instant of the supplied time would be for the Gregorian calendar date January 1, 1970 for a user observing UTC , i.e. the timezone of the time object is ignored.
See getJulianDay(long, long)
for how to determine the Julian day
for the timezone of the time object.
This method can return an incorrect answer when the date / time fields have been set to a local time that contradicts the available timezone information.
Parameters | |
---|---|
time |
Time : the time to test |
Returns | |
---|---|
boolean |
true if epoch. |
normalize
public long normalize (boolean ignoreDst)
Ensures the values in each field are in range. For example if the current value of this calendar is March 32, normalize() will convert it to April 1. It also fills in weekDay, yearDay, isDst and gmtoff.
If "ignoreDst" is true, then this method sets the "isDst" field to -1 (the "unknown" value) before normalizing. It then computes the time in milliseconds and sets the correct value for "isDst" if the fields resolve to a valid date / time.
See toMillis(boolean)
for more information about when to
use true or false for "ignoreDst" and when -1
might be returned.
Parameters | |
---|---|
ignoreDst |
boolean |
Returns | |
---|---|
long |
the UTC milliseconds since the epoch, or -1 |
parse
public boolean parse (String s)
Parses a date-time string in either the RFC 2445 format or an abbreviated format that does not include the "time" field. For example, all of the following strings are valid:
- "20081013T160000Z"
- "20081013T160000"
- "20081013"
allDay
field of this Time class is set to true and the hour
,
minute
, and second
fields are set to zero;
otherwise (a time field was included in the date-time string)
allDay
is set to false. The fields weekDay
,
yearDay
, and gmtoff
are always set to zero,
and the field isDst
is set to -1 (unknown). To set those
fields, call normalize(boolean)
after parsing.
To parse a date-time string and convert it to UTC milliseconds, do
something like this:
Time time = new Time(); String date = "20081013T160000Z"; time.parse(date); long millis = time.normalize(false);
Parameters | |
---|---|
s |
String : the string to parse |
Returns | |
---|---|
boolean |
true if the resulting time value is in UTC time |
Throws | |
---|---|
TimeFormatException |
if s cannot be parsed. |
parse3339
public boolean parse3339 (String s)
Parse a time in RFC 3339 format. This method also parses simple dates (that is, strings that contain no time or time offset). For example, all of the following strings are valid:
- "2008-10-13T16:00:00.000Z"
- "2008-10-13T16:00:00.000+07:00"
- "2008-10-13T16:00:00.000-07:00"
- "2008-10-13"
If the string contains a time and time offset, then the time offset will be used to convert the time value to UTC.
If the given string contains just a date (with no time field), then
the allDay
field is set to true and the hour
,
minute
, and second
fields are set to zero.
Returns true if the resulting time value is in UTC time.
Parameters | |
---|---|
s |
String : the string to parse |
Returns | |
---|---|
boolean |
true if the resulting time value is in UTC time |
Throws | |
---|---|
TimeFormatException |
if s cannot be parsed. |
set
public void set (Time that)
Copy the value of that to this Time object. No normalization happens.
Parameters | |
---|---|
that |
Time |
set
public void set (int second, int minute, int hour, int monthDay, int month, int year)
Sets the fields. Sets weekDay, yearDay and gmtoff to 0, and isDst to -1.
Call normalize(boolean)
if you need those.
Parameters | |
---|---|
second |
int |
minute |
int |
hour |
int |
monthDay |
int |
month |
int |
year |
int |
set
public void set (int monthDay, int month, int year)
Sets the date from the given fields. Also sets allDay to true.
Sets weekDay, yearDay and gmtoff to 0, and isDst to -1.
Call normalize(boolean)
if you need those.
Parameters | |
---|---|
monthDay |
int : the day of the month (in the range [1,31]) |
month |
int : the zero-based month number (in the range [0,11]) |
year |
int : the year |
set
public void set (long millis)
Sets the fields in this Time object given the UTC milliseconds. After this method returns, all the fields are normalized. This also sets the "isDst" field to the correct value.
Parameters | |
---|---|
millis |
long : the time in UTC milliseconds since the epoch. |
setJulianDay
public long setJulianDay (int julianDay)
Sets the time from the given Julian day number, which must be based on the same timezone that is set in this Time object. The "gmtoff" field need not be initialized because the given Julian day may have a different GMT offset than whatever is currently stored in this Time object anyway. After this method returns all the fields will be normalized and the time will be set to 12am at the beginning of the given Julian day.
The only exception to this is if 12am does not exist for that day because of daylight saving time. For example, Cairo, Eqypt moves time ahead one hour at 12am on April 25, 2008 and there are a few other places that also change daylight saving time at 12am. In those cases, the time will be set to 1am.
Parameters | |
---|---|
julianDay |
int : the Julian day in the timezone for this Time object |
Returns | |
---|---|
long |
the UTC milliseconds for the beginning of the Julian day |
setToNow
public void setToNow ()
Sets the time of the given Time object to the current time.
switchTimezone
public void switchTimezone (String timezone)
Convert this time object so the time represented remains the same, but is instead located in a different timezone. This method automatically calls normalize() in some cases.
This method can return incorrect results if the date / time cannot be normalized.
Parameters | |
---|---|
timezone |
String |
toMillis
public long toMillis (boolean ignoreDst)
Converts this time to milliseconds. Suitable for interacting with the
standard java libraries. The time is in UTC milliseconds since the epoch.
This does an implicit normalization to compute the milliseconds but does
not change any of the fields in this Time object. If you want
to normalize the fields in this Time object and also get the milliseconds
then use normalize(boolean)
.
If "ignoreDst" is false, then this method uses the current setting of the "isDst" field and will adjust the returned time if the "isDst" field is wrong for the given time. See the sample code below for an example of this.
If "ignoreDst" is true, then this method ignores the current setting of the "isDst" field in this Time object and will instead figure out the correct value of "isDst" (as best it can) from the fields in this Time object. The only case where this method cannot figure out the correct value of the "isDst" field is when the time is inherently ambiguous because it falls in the hour that is repeated when switching from Daylight-Saving Time to Standard Time.
Here is an example where toMillis(true) adjusts the time, assuming that DST changes at 2am on Sunday, Nov 4, 2007.
Time time = new Time(); time.set(4, 10, 2007); // set the date to Nov 4, 2007, 12am time.normalize(false); // this sets isDst = 1 time.monthDay += 1; // changes the date to Nov 5, 2007, 12am millis = time.toMillis(false); // millis is Nov 4, 2007, 11pm millis = time.toMillis(true); // millis is Nov 5, 2007, 12am
To avoid this problem, use toMillis(true) after adding or subtracting days or explicitly setting the "monthDay" field. On the other hand, if you are adding or subtracting hours or minutes, then you should use toMillis(false).
You should also use toMillis(false) if you want
to read back the same milliseconds that you set with set(long)
or set(android.text.format.Time)
or after parsing a date string.
This method can return -1
when the date / time fields have been
set to a local time that conflicts with available timezone information.
For example, when daylight savings transitions cause an hour to be
skipped: times within that hour will return -1
if isDst =
-1
.
Parameters | |
---|---|
ignoreDst |
boolean |
Returns | |
---|---|
long |
toString
public String toString ()
Return the current time in YYYYMMDDTHHMMSS<tz> format
Returns | |
---|---|
String |
a string representation of the object. |