CODEWITHSUNDEEP
javaandroid
atomicode
atomicode

Reputation: 571

What is the reason ScheduledExecutorService is not executing while display is off?

Im fairly new to Android and have encountered a problem, which i would like to understand. The problem is that the java.util.concurrent.ScheduledExecutorService doesn't seem to issue its tasks while the display of my smartphone is off. I was using a java.util.Timer before which didn't have this issue, but was transitioning to ScheduledExecutorService because of the need to wait for the end of the task execution after stoping the Timer. The Timer is used in a Service running in the background.

Note: Using AlarmManager isn't an option, because i want to understand the problem with ScheduleExecutorService or else will use Timer again (synchronizing the shutdown).

Here is how the task is scheduled:

mScheduler = Executors.newSingleThreadScheduledExecutor();
mScheduler.scheduleAtFixedRate(mTask, 1, 1, TimeUnit.SECONDS);

To furher clarify the purpose: I am trying to update a Notification as well as parts of the User Interface periodically, this doesn't need to be done if the device wants to go into "sleep" mode, but i would need to handle this case. I think understanding why ScheduledExecutorService is behavoring the way it does compared to Timer will help me handle it.

UPDATE:

As recommended by Chris Stratton, i'm using a BroadcastReceiver to receive the Intent.ACTION_SCREEN_ON and Intent.ACTION_SCREEN_OFF Intents to pause/resume the ScheduledExecutorService, which works like a charm. However there seems to be another issue with the ScheduledExecutorService while having a phone call, the execution doesn't stop but seems to be throttled somehow. This is only the case if the screen is turned off due to the proximity sensor (no intents are received in this case either)...

Upvotes: 4

Views: 1494

Answers (1)

Yaroslav Mytkalyk
Yaroslav Mytkalyk

Reputation: 17115

When the screen is off, if no other applications are holding WakeLock, the CPU suspends.

You should use a PARTIAL WakeLock whenever you need something done while screen is off.

And make sure you release it as soon as you've done all the ackground job.

Upvotes: 1

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