AlarmManagerpublic class AlarmManager extends Object | This class provides access to the system alarm services. These allow you
to schedule your application to be run at some point in the future. When
an alarm goes off, the {@link Intent} that had been registered for it
is broadcast by the system, automatically starting the target application
if it is not already running. Registered alarms are retained while the
device is asleep (and can optionally wake the device up if they go off
during that time), but will be cleared if it is turned off and rebooted.
The Alarm Manager holds a CPU wake lock as long as the alarm receiver's
onReceive() method is executing. This guarantees that the phone will not sleep
until you have finished handling the broadcast. Once onReceive() returns, the
Alarm Manager releases this wake lock. This means that the phone will in some
cases sleep as soon as your onReceive() method completes. If your alarm receiver
called {@link android.content.Context#startService Context.startService()}, it
is possible that the phone will sleep before the requested service is launched.
To prevent this, your BroadcastReceiver and Service will need to implement a
separate wake lock policy to ensure that the phone continues running until the
service becomes available.
Note: The Alarm Manager is intended for cases where you want to have
your application code run at a specific time, even if your application is
not currently running. For normal timing operations (ticks, timeouts,
etc) it is easier and much more efficient to use
{@link android.os.Handler}.
You do not
instantiate this class directly; instead, retrieve it through
{@link android.content.Context#getSystemService
Context.getSystemService(Context.ALARM_SERVICE)}. |
| Fields Summary |
|---|
| public static final int | RTC_WAKEUPAlarm time in {@link System#currentTimeMillis System.currentTimeMillis()}
(wall clock time in UTC), which will wake up the device when
it goes off. | | public static final int | RTCAlarm time in {@link System#currentTimeMillis System.currentTimeMillis()}
(wall clock time in UTC). This alarm does not wake the
device up; if it goes off while the device is asleep, it will not be
delivered until the next time the device wakes up. | | public static final int | ELAPSED_REALTIME_WAKEUPAlarm time in {@link android.os.SystemClock#elapsedRealtime
SystemClock.elapsedRealtime()} (time since boot, including sleep),
which will wake up the device when it goes off. | | public static final int | ELAPSED_REALTIMEAlarm time in {@link android.os.SystemClock#elapsedRealtime
SystemClock.elapsedRealtime()} (time since boot, including sleep).
This alarm does not wake the device up; if it goes off while the device
is asleep, it will not be delivered until the next time the device
wakes up. | | private final IAlarmManager | mService | | public static final long | INTERVAL_FIFTEEN_MINUTESAvailable inexact recurrence intervals recognized by
{@link #setInexactRepeating(int, long, long, PendingIntent)} | | public static final long | INTERVAL_HALF_HOUR | | public static final long | INTERVAL_HOUR | | public static final long | INTERVAL_HALF_DAY | | public static final long | INTERVAL_DAY |
| Constructors Summary |
|---|
AlarmManager(IAlarmManager service)package private on purpose
mService = service;
|
| Methods Summary |
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| public void | cancel(PendingIntent operation)Remove any alarms with a matching {@link Intent}.
Any alarm, of any type, whose Intent matches this one (as defined by
{@link Intent#filterEquals}), will be canceled.
try {
mService.remove(operation);
} catch (RemoteException ex) {
}
| | public void | set(int type, long triggerAtTime, PendingIntent operation)Schedule an alarm. Note: for timing operations (ticks, timeouts,
etc) it is easier and much more efficient to use
{@link android.os.Handler}. If there is already an alarm scheduled
for the same IntentSender, it will first be canceled.
If the time occurs in the past, the alarm will be triggered
immediately. If there is already an alarm for this Intent
scheduled (with the equality of two intents being defined by
{@link Intent#filterEquals}), then it will be removed and replaced by
this one.
The alarm is an intent broadcast that goes to a broadcast receiver that
you registered with {@link android.content.Context#registerReceiver}
or through the <receiver> tag in an AndroidManifest.xml file.
Alarm intents are delivered with a data extra of type int called
{@link Intent#EXTRA_ALARM_COUNT Intent.EXTRA_ALARM_COUNT} that indicates
how many past alarm events have been accumulated into this intent
broadcast. Recurring alarms that have gone undelivered because the
phone was asleep may have a count greater than one when delivered.
try {
mService.set(type, triggerAtTime, operation);
} catch (RemoteException ex) {
}
| | public void | setInexactRepeating(int type, long triggerAtTime, long interval, PendingIntent operation)Schedule a repeating alarm that has inexact trigger time requirements;
for example, an alarm that repeats every hour, but not necessarily at
the top of every hour. These alarms are more power-efficient than
the strict recurrences supplied by {@link #setRepeating}, since the
system can adjust alarms' phase to cause them to fire simultaneously,
avoiding waking the device from sleep more than necessary.
Your alarm's first trigger will not be before the requested time,
but it might not occur for almost a full interval after that time. In
addition, while the overall period of the repeating alarm will be as
requested, the time between any two successive firings of the alarm
may vary. If your application demands very low jitter, use
{@link #setRepeating} instead.
try {
mService.setInexactRepeating(type, triggerAtTime, interval, operation);
} catch (RemoteException ex) {
}
| | public void | setRepeating(int type, long triggerAtTime, long interval, PendingIntent operation)Schedule a repeating alarm. Note: for timing operations (ticks,
timeouts, etc) it is easier and much more efficient to use
{@link android.os.Handler}. If there is already an alarm scheduled
for the same IntentSender, it will first be canceled.
Like {@link #set}, except you can also
supply a rate at which the alarm will repeat. This alarm continues
repeating until explicitly removed with {@link #cancel}. If the time
occurs in the past, the alarm will be triggered immediately, with an
alarm count depending on how far in the past the trigger time is relative
to the repeat interval.
If an alarm is delayed (by system sleep, for example, for non
_WAKEUP alarm types), a skipped repeat will be delivered as soon as
possible. After that, future alarms will be delivered according to the
original schedule; they do not drift over time. For example, if you have
set a recurring alarm for the top of every hour but the phone was asleep
from 7:45 until 8:45, an alarm will be sent as soon as the phone awakens,
then the next alarm will be sent at 9:00.
If your application wants to allow the delivery times to drift in
order to guarantee that at least a certain time interval always elapses
between alarms, then the approach to take is to use one-time alarms,
scheduling the next one yourself when handling each alarm delivery.
try {
mService.setRepeating(type, triggerAtTime, interval, operation);
} catch (RemoteException ex) {
}
| | public void | setTimeZone(java.lang.String timeZone)
try {
mService.setTimeZone(timeZone);
} catch (RemoteException ex) {
}
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