android.app
Class AlarmManager

java.lang.Object
  android.app.AlarmManager

public 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 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.

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 Handler.

You do not instantiate this class directly; instead, retrieve it through Context.getSystemService(Context.ALARM_SERVICE).

Field Summary

static int	ELAPSED_REALTIME Alarm time in SystemClock.elapsedRealtime() (time since boot, including sleep).
static int	ELAPSED_REALTIME_WAKEUP Alarm time in SystemClock.elapsedRealtime() (time since boot, including sleep), which will wake up the device when it goes off.
static int	RTC Alarm time in System.currentTimeMillis() (wall clock time in UTC).
static int	RTC_WAKEUP Alarm time in System.currentTimeMillis() (wall clock time in UTC), which will wake up the device when it goes off.

Method Summary

void	cancel(PendingIntent operation) Remove any alarms with a matching Intent.
void	set(int type, long triggerAtTime, PendingIntent operation) Schedule an alarm.
void	setRepeating(int type, long triggerAtTime, long interval, PendingIntent operation) Schedule a repeating alarm.
void	setTimeZone(String timeZone)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

RTC_WAKEUP

public static final int RTC_WAKEUP

Alarm time in System.currentTimeMillis() (wall clock time in UTC), which will wake up the device when it goes off.
Constant Value: 0 (0x00000000)

See Also:

Constant Field Values

RTC

public static final int RTC

Alarm time in 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.
Constant Value: 1 (0x00000001)

See Also:

Constant Field Values

ELAPSED_REALTIME_WAKEUP

public static final int ELAPSED_REALTIME_WAKEUP

Alarm time in SystemClock.elapsedRealtime() (time since boot, including sleep), which will wake up the device when it goes off.
Constant Value: 2 (0x00000002)

See Also:

Constant Field Values

ELAPSED_REALTIME

public static final int ELAPSED_REALTIME

Alarm time in 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.
Constant Value: 3 (0x00000003)

See Also:

Constant Field Values

Method Detail

set

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 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 filterEquals(Intent)), then it will be removed and replaced by this one.

The alarm is an intent broadcast that goes to an intent receiver that you registered with registerReceiver(BroadcastReceiver, IntentFilter) or through the <receiver> tag in an AndroidManifest.xml file.

Alarm intents are delivered with a data extra of type int called 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.

Parameters:

type - One of ELAPSED_REALTIME, ELAPSED_REALTIME_WAKEUP, RTC or RTC_WAKEUP.

triggerAtTime - Time the alarm should go off, using the appropriate clock (depending on the alarm type).

operation - Action to perform when the alarm goes off; typically comes from IntentSender.getBroadcast().

See Also:

Handler, setRepeating(int, long, long, PendingIntent), cancel(PendingIntent), sendBroadcast(Intent), registerReceiver(BroadcastReceiver, IntentFilter), filterEquals(Intent), ELAPSED_REALTIME, ELAPSED_REALTIME_WAKEUP, RTC, RTC_WAKEUP

setRepeating

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 Handler. If there is already an alarm scheduled for the same IntentSender, it will first be canceled.

Like set(int, long, PendingIntent), except you can also supply a rate at which the alarm will repeat. This alarm continues repeating until explicitly removed with cancel(PendingIntent). 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.

Parameters:

type - One of ELAPSED_REALTIME, ELAPSED_REALTIME_WAKEUP}, RTC or RTC_WAKEUP.

triggerAtTime - Time the alarm should first go off, using the appropriate clock (depending on the alarm type).

interval - Interval between subsequent repeats of the alarm.

operation - Action to perform when the alarm goes off; typically comes from IntentSender.getBroadcast().

See Also:

Handler, set(int, long, PendingIntent), cancel(PendingIntent), sendBroadcast(Intent), registerReceiver(BroadcastReceiver, IntentFilter), filterEquals(Intent), ELAPSED_REALTIME, ELAPSED_REALTIME_WAKEUP, RTC, RTC_WAKEUP

cancel

public void cancel(PendingIntent operation)

Remove any alarms with a matching Intent. Any alarm, of any type, whose Intent matches this one (as defined by filterEquals(Intent)), will be canceled.

Parameters:

operation - IntentSender which matches a previously added IntentSender.

See Also:

set(int, long, PendingIntent)

setTimeZone

public void setTimeZone(String timeZone)