| java.lang.Object | |
| ↳ | java.util.TimeZone |
 Known Direct Subclasses
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TimeZone represents a time zone, primarily used for configuring a Calendar or
SimpleDateFormat instance.
Most applications will use getDefault() which returns a TimeZone based on
the time zone where the program is running.
You can also get a specific TimeZone by Olson ID.
It is highly unlikely you'll ever want to use anything but the factory methods yourself.
Let classes like Calendar and SimpleDateFormat do the date
computations for you.
If you do need to do date computations manually, there are two common cases to take into account:
useDaylightTime() method will always return true, and inDaylightTime(Date)
must be used to determine whether or not daylight time applies to a given Date.
The getRawOffset() method will return a raw offset of (in this case) -8 hours from UTC,
which isn't usually very useful. More usefully, the getOffset(int, int, int, int, int, int) methods return the
actual offset from UTC for a given point in time; this is the raw offset plus (if the
point in time is in daylight time) the applicable
DST savings (usually, but not necessarily, 1 hour).
useDaylightTime() and inDaylightTime(Date) methods both always return false,
and the raw and actual offsets will always be the same.
Note the type returned by the factory methods getDefault() and getTimeZone(String) is
implementation dependent. This may introduce serialization incompatibility issues between
different implementations. Android returns instances of SimpleTimeZone so that
the bytes serialized by Android can be deserialized successfully on other
implementations, but the reverse compatibility cannot be guaranteed.
| Constants | |||||||||||
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| int | LONG | The long display name style, such as Pacific Daylight Time. |
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| int | SHORT | The short display name style, such as PDT. |
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| Public Constructors | |||||||||||
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| Public Methods | |||||||||||
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Returns a new time zone with the same ID, raw offset, and daylight
savings time rules as this time zone.
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Returns the system's installed time zone IDs.
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Returns the IDs of the time zones whose offset from UTC is
offsetMillis. | |||||||||||
Returns the latest daylight savings in milliseconds for this time zone, relative
to this time zone's regular UTC offset (as returned by
getRawOffset()). | |||||||||||
Returns the user's preferred time zone.
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Equivalent to
getDisplayName(false, TimeZone.LONG, locale). | |||||||||||
Equivalent to
getDisplayName(false, TimeZone.LONG, Locale.getDefault()). | |||||||||||
Equivalent to
getDisplayName(daylightTime, style, Locale.getDefault()). | |||||||||||
Returns the ID of this
TimeZone, such as
America/Los_Angeles, GMT-08:00 or UTC. | |||||||||||
Returns this time zone's offset in milliseconds from UTC at the specified
date and time.
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Returns the offset in milliseconds from UTC for this time zone at
time. | |||||||||||
Returns the offset in milliseconds from UTC of this time zone's standard
time.
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Returns a
TimeZone corresponding to the given id, or GMT
for unknown ids. | |||||||||||
Returns true if
timeZone has the same rules as this time zone. | |||||||||||
Returns true if
time is in a daylight savings time period for
this time zone. | |||||||||||
Overrides the default time zone for the current process only.
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Sets the ID of this
TimeZone. | |||||||||||
Sets the offset in milliseconds from UTC of this time zone's standard
time.
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Returns true if this time zone has a future transition to or from
daylight savings time.
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[Expand]
Inherited Methods | |||||||||||
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From class
java.lang.Object
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The long display name style, such as Pacific Daylight Time.
Requests for this style may yield GMT offsets like GMT-08:00.
The short display name style, such as PDT. Requests for this
style may yield GMT offsets like GMT-08:00.
Returns a new time zone with the same ID, raw offset, and daylight savings time rules as this time zone.
Returns the system's installed time zone IDs. Any of these IDs can be
passed to getTimeZone(String) to lookup the corresponding time zone
instance.
Returns the IDs of the time zones whose offset from UTC is offsetMillis. Any of these IDs can be passed to getTimeZone(String) to
lookup the corresponding time zone instance.
Returns the latest daylight savings in milliseconds for this time zone, relative
to this time zone's regular UTC offset (as returned by getRawOffset()).
This class returns 3600000 (1 hour) for time zones
that use daylight savings time and 0 for timezones that do not,
leaving it to subclasses to override this method for other daylight savings
offsets. (There are time zones, such as Australia/Lord_Howe,
that use other values.)
Note that this method doesn't tell you whether or not to apply the
offset: you need to call inDaylightTime for the specific time
you're interested in. If this method returns a non-zero offset, that only
tells you that this TimeZone sometimes observes daylight savings.
Note also that this method doesn't necessarily return the value you need to apply to the time you're working with. This value can and does change over time for a given time zone.
It's highly unlikely that you should ever call this method. You
probably want getOffset(int, int, int, int, int, int) instead, which tells you the offset
for a specific point in time, and takes daylight savings into account for you.
Returns the user's preferred time zone. This may have been overridden for
this process with setDefault(TimeZone).
Since the user's time zone changes dynamically, avoid caching this value. Instead, use this method to look it up for each use.
Equivalent to getDisplayName(false, TimeZone.LONG, locale).
Equivalent to getDisplayName(false, TimeZone.LONG, Locale.getDefault()).
Be wary of the default locale.
Equivalent to getDisplayName(daylightTime, style, Locale.getDefault()).
Be wary of the default locale.
Returns the ID of this TimeZone, such as
America/Los_Angeles, GMT-08:00 or UTC.
Returns this time zone's offset in milliseconds from UTC at the specified date and time. The offset includes daylight savings time if the date and time is within the daylight savings time period.
This method is intended to be used by Calendar to compute
DST_OFFSET and ZONE_OFFSET. Application
code should have no reason to call this method directly. Each parameter
is interpreted in the same way as the corresponding Calendar
field. Refer to Calendar for specific definitions of this
method's parameters.
Returns the offset in milliseconds from UTC for this time zone at time. The offset includes daylight savings time if the specified
date is within the daylight savings time period.
| time | the date in milliseconds since January 1, 1970 00:00:00 UTC |
|---|
Returns the offset in milliseconds from UTC of this time zone's standard time.
Returns a TimeZone corresponding to the given id, or GMT
for unknown ids.
An ID can be an Olson name of the form Area/Location, such
as America/Los_Angeles. The getAvailableIDs() method returns
the supported names.
This method can also create a custom TimeZone given an ID with the following
syntax: GMT[+|-]hh[[:]mm]. For example, "GMT+05:00", "GMT+0500",
"GMT+5:00", "GMT+500", "GMT+05", and "GMT+5" all return
an object with a raw offset of +5 hours from UTC, and which does not use daylight
savings. These are rarely useful, because they don't correspond to time zones actually
in use by humans.
Other than the special cases "UTC" and "GMT" (which are synonymous in this context, both corresponding to UTC), Android does not support the deprecated three-letter time zone IDs used in Java 1.1.
Returns true if timeZone has the same rules as this time zone.
The base implementation returns true if both time zones have the same raw offset.
Returns true if time is in a daylight savings time period for
this time zone.
Overrides the default time zone for the current process only.
Warning: avoid using this method to use a custom time zone in your process. This value may be cleared or overwritten at any time, which can cause unexpected behavior. Instead, manually supply a custom time zone as needed.
| timeZone | a custom time zone, or null to set the default to
the user's preferred value.
|
|---|
Sets the offset in milliseconds from UTC of this time zone's standard time.
Returns true if this time zone has a future transition to or from daylight savings time.
Warning: this returns false for time zones like
Asia/Kuala_Lumpur that have previously used DST but do not
currently. A hypothetical country that has never observed daylight
savings before but plans to start next year would return true.
Warning: this returns true for time zones that use DST, even when it is not active.
Use inDaylightTime(Date) to find out whether daylight savings is
in effect at a specific time.
Most applications should not use this method.