AlarmManager on API19 has the method setExact() to set an exact alarm.
Exact means --> If I set an alarm to 2:01 pm it will be triggered at 2:01 pm
On API 23 - Marhsmwallow (6.0) there is a new method setExactAndAllowWhileIdle(), but as of the reference it is not EXACT because it will trigger only every minute and in low power idle mode only every 15 minutes.
Exact != every 15 minutes :-)
So how can I achieve an exact alarm with AlarmManager in 6.0?
If a user adds a reminder or a calendar appointment and wants to be informed 10 minutes before the event it should show the alarm EXACT 10 minutes before the event. With setExactAndAllowWhileIdle() this seems is not possible.
Reference Link:
http://developer.android.com/reference/android/app/AlarmManager.html#setExactAndAllowWhileIdle(int, long, android.app.PendingIntent)
So how can I achieve an exact alarm with AlarmManager in 6.0?
You are welcome to try setAlarmClock(), as AFAIK it is unaffected by Doze mode. Otherwise, AlarmManager is not a viable option for you. Even having your app on the battery optimization whitelist will not help, as AlarmManager behavior does not change based on the whitelist.
You are welcome to use GCM, as a high-priority message should give you an opportunity to alert the user. This, of course, requires network connectivity.
The only offline solution that I am aware of — and that I am presently testing — is to have the user add your app to the battery optimization whitelist, then use a foreground service (to try to keep your process around), a ScheduledExecutorService (for the timing), and a partial WakeLock (to keep the CPU on). This will be fairly devastating to the user's battery.
Using setExactAndAllowWhileIdle() for a one-time alarm will fire exactly on the given time even in Doze idle mode. So this probably is the way to go.
Problems start, if you want to repeat the alarm at a rate of < 15 min (or set any other at a time < 15 min away from the last one), as this will not work in Doze idle mode, where such alarms are forced to the next 15 min or are executed when idle maintenance starts, which happens for about ten minutes first after 1 hour, then after another 2 hours, then after another 4 hours and so on.
- EDIT -
As of today Nov 17, Dianne Hackborn writes in this Post's comments:
"For what it's worth, the minimum time between while idle alarms will be changing to 9 minutes at some point relatively soon (even on devices running the current Marshmallow builds)."
This doesn't change anything fundamentally though.
Here are my discussion with Ian Lake on Google+!
setExactAndAllowWhileIdle() is exact and should work.
The 15 minutes time frame is wrong in the java doc.
I was trying to create an automation system running in the background. My frequency range was between 1-15 minutes. My wish was not to use a foreground service. By looking at the name of the method "setExactAndAllowWhileIdle", I thought that yeah it is safe to go with one-time alarms, scheduling the next one when done.
However, I couldn't find a way to run code in doze mode with alarms running more frequent than 15 minutes. Instead, I choose to start a foreground service when doze mode gets activated and stop that foreground service when phone awakes. User won't be seeing your foreground notification while using his/her phone. I don't care much about the ones in doze mode.
PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if(intent.getAction().equals("android.os.action.DEVICE_IDLE_MODE_CHANGED")){
if (pm.isDeviceIdleMode()) {
//startAutomationForegroundService();
} else {
//stopAutomationForegroundService();
return;
}
AutomationReceiver.completeWakefulIntent(intent);
return;
}
}
You need to register "android.os.action.DEVICE_IDLE_MODE_CHANGED" intent filter into your WakefulBroadcastReceiver. Care putting it into manifest may not help.
Related
I have two questions.
I want fire a Broadcast receiver using AlarmManager and show a notification in onReceive method. Should I use from WakeLoke for this?
What is different between setAlarmClock() and setExactAndAllowWhileIdle() ?
I use (as you wrote) the onReceive method to start a newWakeLock and it works fine for me.
The difference lies in the behavior in doze mode (Doze Mode: https://developer.android.com/training/monitoring-device-state/doze-standby).
I do not know your exact problem, but I worked very hard to develop an app which contains few timers and every timer should make a notification at the exact time even the screen is locked and the device is in the doze mode. My solution is to fire an Broadcast over an AlarmManager with the setExact(...) method.
Answer your question in reverse order
.2. setExactWhileIdle guarantees that if the system is not sleeping and not in doze, the alarm will go off within 1 minute of the given time. if the system is in doze mode, the alarm will go off within 15 minutes of the given time. In practice, if the system is not in doze mode or low on battery, the alarm will go off on time. On the other hand, setAlarmClock is the closest one can get to a guarentee that the system will deliver the alarm at a specific time; this does come at a relatively large drain on battery. So, if your goal is to implement highly time sensitive notifications such as an alarm clock, then use setAlarmClock. Otherwise try to avoid it.
.1. according to the documentation, upon an alarm being dispatched from setExactAndAllowWhildIdle or setAlarmClock:
the app will also be added to the system's temporary power exemption list for approximately 10 seconds to allow that application to acquire further wake locks in which to complete its work.
My suggestion is that if all you are doing is posting a notification, then a wake lock is not necessary. Otherwise, if you are doing longer running work, use a wake lock
Obligatory Disclaimer: battery drain is a real thing. please don't make an app that drains the battery. do everything in your power to design your app not to disturb the systems power optimization. All exact alarms and especially setAlarmClock disrupt the systems attempts to optimize battery. If its necessary, then its necessary. Otherwise, do not do it.
I have a requirement where i have to send some data to server every hour even in doze mode, active mode or sleep mode. Work manager document says that it respects doze mode. I just want to know is there any way i can achieve this ?
Minsdkversion is 21.
Support china store.
Want to support OS 8 and 9 too.
What is setRequiresDeviceIdle(true) constraint in workmanager ? Does it works only in doze mode ?
Any other way apart from WorkManager i can achieve this?
As of right now, the only way that I know of to ensure that your application will send a notification at the right time, 100% of the time, is using AlarmManager - Alarm Clock
Otherwise, AlarmManager setExactAndAllowWhileIdle (as of API 27) will not always work in doze mode. Same thing with WorkManager. Basically, you'll need to create your Worker and set an AlarmClock within it to start the Worker up again in an hour. The caveat is that this behaves as you'd expect with an AlarmClock, noises, vibrations, etc.
I am using AlarmManager in our app to set alarms that are set at specific date and time. Now recently few users of our app are complaining that these alarms are not popping up. Also, in Android O guidelines, it is mentioned that app should not run any background service and instead should switch to Firebase JobDispatcher. I have following 2 questions
In our app, we do not do any background task except to show notification to user at the specified time and date. Even in this case, should we switch to Firebase Jobdispatcher?
In case we do need to switch to JobDispatcher, how can the Job be set to run at exactly specific date and time?
Because you're not doing any background tasks like network requests or long running CPU operations, I think you should continue using Alarm Manager.
Now recently few users of our app are complaining that these alarms are not popping up.
This is because when doze mode triggers, it is not guaranteed that your alarms will be triggered(see this).
What you can do is use setAndAllowWhileIdle() or setExactAndAllowWhileIdle() methods from AlarmManager class as per your requirement for API level >= 23.
According to the documentation these are appropriate for notification purposes.
setAndAllowWhileIdle() documentation:
Like set(int, long, PendingIntent), but this alarm will be allowed to
execute even when the system is in low-power idle modes. This type of
alarm must only be used for situations where it is actually required
that the alarm go off while in idle -- a reasonable example would be
for a calendar notification that should make a sound so the user is
aware of it. When the alarm is dispatched, the app will also be added
to the system's temporary whitelist for approximately 10 seconds to
allow that application to acquire further wake locks in which to
complete its work.
This Doze mode makes it quite hard for me to implement proper alarms system. Basically I want to allow my user to run a webservice call each 15 or 30 minutes for instance. So let's say the user sets the app to run the alarm each 30 minutes. While the device is normal use, the alarms will fire more or less exact (I'm using setRepeating) but it's good enough for my purpose.
When the device is dozing, as per docs, my repeating alarms do not fire, BUT when the device exits doze mode, all the alarms that did not run, run one after another(or similar). So I end up in the morning with maybe 4-6 alarms fired one after another, all fetching the same data from the webservice. Or same thing when a maintenance window occurs...
Is there a way to tell the doze mode that if my alarm did not fire at required time, to not run it at all? Or if there are multiple alarms that did not fire, only fire the last one?
LE: I had an error in code which ran the alarm too often, that is why I had the impression that postponed alarms will all run one after another...
I'm using alarm manager in my service to set non-waking alarms every 15 seconds to execute a certain task. I don't want to wake the phone up as the task isn't time critical, so i'm using the ELAPSED_REALTIME flag to set the alarm. Here's the code:
alarm.setRepeating(AlarmManager.ELAPSED_REALTIME, SystemClock.elapsedRealtime(), 15 * 1000, intentRecurringChecks);
What I'm noticing in my logs is that the task is getting executed every 15 seconds. Does this mean the phone is staying awake even though it's screen has been turned off for half an hour? Is there a way I can be sure my application's not the one waking up the phone?
I've search about this topic but I can't find a proper answer.
Thanks for your help.
First, you shouldn't use AlarmManager for such timeouts. This is explicitly mentioned in documentation (read the bold part). It's better to use Handler based timers in your case. Here is an example: Repeat a task with a time delay?.
Second, when device is connected via USB, its not going to deep sleep mode. You should disconnect your device wait a minute or two. Attach it back and analyze the logs.