I have a single process app that includes a service component (started by the activity and runs all the time) with multiple threads. I need an app to be repeatedly suspended (deep sleep) for 7 seconds and then to start an accelerometer for a very brief period of time (the accelerometer is stopped after collecting 20 samples) in order to save on battery. It has to run on all android platforms preferably above 2.3.
My first approach was to implement a timer in the service component using Handler based sendMessageDelayed method (delay = 7 seconds) called after the accelerometer is stopped, without acquiring a partial wake lock. However it looks to me that this isn't a good approach, because the timer only counts the ticks when the phone is not asleep (please correct me here if I am wrong or there is solution to this issue).
My second approach was the same as the first, but with acquiring a partial wake lock before calling sendmesssageDelayed. It works okay, but there is too much battery consumption.
So here few questions:
Should I use AlarmManager to fire broadcasts every 7 seconds? My concern is that 7 seconds is too short time for AlarmManager, because it internally acquires a partial wakelock for a substantial amount of time. I wonder if anybody has done a performance analysis for the maximum time that the Wakelock will be acquired by the AlarmManager, or has an alternative approach. I read other posts that said that AlarmManager is effective solution, but it is especially useful for long periods of time.
If AlarmManager has to be used can I acquire a partial wakelock in broadcast receiver using a wakelock object maintained as a public static field in the service component (so it is easily accessed from any other component in the app)?
Also are there any issues of accessing and using a Handler based object from broadcast receiver to notify a service thread that Alarm broadcast was received? (The handler object is maintained as a static public field in the service component, so it is easily accessed from any other component in the app).
Thank you very much for your help
If you use a service that's always running there's no need to use Alarmmanager. Handler is easier. Every 7 seconds is a lot, are you sure you want that? I mean, if you mention "battery conservation"? Keeping a service running is expensive, not for the service itself, but for the things it keeps awake that use juice.