Neither setAndAllowWhileIdle() nor setExactAndAllowWhileIdle() can fire alarms more than once per 15 minutes per app. I want my alarm-manager to update local log after every minute. I have tried both mentioned alarm manager but none of them works as they automatically stop after some hours. Please Help me how to achieve.
You can use Foreground service and handler to run your task every minute. You can't use AlarmManager or WorkManager because their minimum interval is 15 minutes.
I am new to Android Job Scheduler, I want to run a task every day morning 9AM without using Alarm manager.
If you are not using AlarmManager, then you won't be able to guarantee that your task will be executed at 9 AM. If its not crucial, you can use WorkManager or JobScheduler, depending on your need.
Note: Using either of these will not guarantee that your job will be executed exactly at 9AM. These will respect doze mode and the job will be executed once during the specified interval which controlled by OS.
I am implementing a widget that checks on-line train departure times between every minute and every hour, depending on the time of day.
Calling the service with
manager.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP,
SystemClock.elapsedRealtime() - 10000, 60000, pendingIntent)
works fine, but for debugging I would like to reduce the interval to about 10 seconds which cannot be done because of the 1-minute limit in more recent versions of Android. Clearly, I don't care about battery life in the emulator.
As far as I understand, using an Hander/Timer is not an option, because it required the task to be in the foreground. Is a visible widget "in the forground"?
What is the recommended practice in this case?
you actually have to tasks
configure the alarmmanager to add/remove trigger events via intents
interprete the events with intents in a service
If you seperate both you can easily create a very simple gui/activity that does the same as the alarmmanager would do when being triggerd and that you can debug:
* onSendButtonClick: create and send pendingIntent
for the alarmmanager-handling i would implement logging into a text file each time alarmmanager is added/removed/triggered.
Be prepared that newer android versions may postpone alarmmanager events to save energy until the device is already active and that intervals less than 15 minutes may not work.
you may also need on_boot_complete to reconfigure alarmmanager after device-shutdown
I need to set a repeating alarm every X hours that would even fire in doze mode. However, the only Apis available in AlarmManager for Android 23 are setExactAndAllowWhileIdle and setAndAllowWhileIdle which are not for repeating alarms.
I am wondering if I should reschedule the alarm every time it fires? or is there any better solution?
I am wondering if I should reschedule the alarm every time it fires?
That is exactly what you should do.
The idea behind doze is to attempt to prevent draining the battery. Repeated alarms drain battery, so the builtin way to repeat alarms by passing an extra parameter was removed in android 6. It can still be done, but as you were wondering, that requires you to manually reschedule the alarm.
Be sure to reschedule the alarm immediately when it fires, before doing anything else that could go wrong and prevent the alarm from being rescheduled.
What are the parameters of the following:
alarmMgr.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(),
AlarmManager.INTERVAL_FIFTEEN_MINUTES, alarmIntent);
And of the following:
alarmMgr.setInexactRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(),
AlarmManager.INTERVAL_DAY, alarmIntent);
What is the difference and also how are the two different in terms of functionality?
Both examples schedule a repeating alarm that will send the given alarmIntent. On both cases, the first time it is sent will be immediate (calendar.getTimeInMillis() returns the current time). On both cases, the device will be woken up when the alarm needs to be sent (as evident by AlarmManager.RTC_WAKEUP).
There are two differences between these calls. The simpler one is that the intent will be sent every fifteen minutes on the first call, and every day on the second call (as you can see in the third parameter). The more complicated difference is the function call itself: setRepeating will schedule the first alarm for exactly every fifteen minutes; setInexactRepeating will schedule the second alarm for approximately every 24 hours, meaning it might deviate from that interval - with the advantage of consuming less power.
Do notice that this has changed in API 19, where these two calls are synonymous. See this guide, and this API documentation.
Decide how precise your alarm needs to be
Choosing the alarm type is often the first step in creating an alarm. A further distinction is how precise you need your alarm to be.
For most apps, setInexactRepeating() is the right choice. When you use this method, Android synchronizes multiple inexact repeating alarms and fires them at the same time. This reduces the drain on the battery.
For the rare app that has rigid time requirements as example, the alarm needs to fire precisely at 4:00 p.m. everyday then use setRepeating().
Reference: Decide how precise your alarm needs to be
To augment previous answers, there are a number of other best practices to consider when using repeating alarms, particularly inexact alarms requested using setInexactRepeating().
Alarm Type
Non-WAKEUP alarms are better than WAKEUP alarms from a power management perspective. Using the former your alarm may fire late, but it will still fire either when the device is woken by the user, or when another wakeup alarm fires. Using WAKEUP alarms will wake the device out of sleep, consuming additional battery and potentially causing other inexact alarms to fire that have been delayed that could otherwise have been delayed longer (reducing the batching power-saving benefits that inexact alarms provide).
Prefer alarms using the ELAPSED timebase rather than the RTC timebase. The former are more likely to have a more random distribution across devices than RTC alarms, which reduces the risk of network congestion and on the server if the alarm is triggering some sort of poll. Phones running Gingerbread (or older) suffer from a bug whereby RTC inexact alarms have a tendency to align closely to the real-time clock, e.g. approximately 30s past each quarter of an hour. ELAPSED alarms don't suffer from this bug on these earlier platform versions. Even if your alarm doesn't trigger any network activity, remember that if it is a wakeup alarm it may trigger other alarm non-wakeup intents that may hit the network.
Timebase
Be careful to specify the requested start time in the correct time domain for the alarm type. Failure to do this can result in alarms being set in the past (they fire right away) if setting an RTC alarm with an ELAPSED timebase or far in the future if setting an ELAPSED alarm using the RTC timebase. You can check what alarms an app has scheduled using dumpsys alarm via the adb shell.
Interval
Specifying an inexact alarm interval of anything other than the interval constants defined in the AlarmManager API is redundant on SDK <19: they will be scheduled as exact not inexact alarms, losing all the power-saving benefits that inexact alarms provide.
Edit: here's further explanation of the bug relating to gingerbread and honeycomb 3.0 devices: https://code.google.com/p/android/issues/detail?id=31550
setRepeating is more accurate and setInexactRepeating is for saving battery but no accurate , setInexactRepeating is good for maintenance in background for example and setRepeating is necessary for example for alarm clock .
Use setInexactRepeating() is used when app is not seriously used to required for example wake up early in the morning . if Alarm wake up approximately that time there is no any life dangeous.
like medicine pills app where highly critical patient use that app to reminde nurse or doctor staff the is compulsory to use setRepeating().
When you use setInexactRepeating()
then Android synchronizes repeating alarms from multiple apps and fires them at the same time(once). This reduces the total number of times the system must wake the device.
thus reducing drain on the battery.
repeating alarms are inexact. Note that while setInexactRepeating() is an improvement over setRepeating() also
it can still overwhelm a server if every instance of an app hits the server around the same time. Therefore, for network requests, add some randomness to your alarms.