android monitoring apps

Question

I would like to create an Android application with real-time monitoring functions. One monitoring function is to audit the audio flow. The other function is to interact with a peripheral sensor. These monitoring functions can be triggered by others. Besides, in order to save power consumption, the audio function will be running in a polling mode, i.e. sleep for a certain amount of time and wake for a certain amount of time.

I am considering how to design the Android application.

• Whether to design the audio function as a Service or an Activity? The problem is if it is designed as an Activity, the audio function will be off if screen turns off after a period of time.

• How to design the polling function? Use an AlarmManager or a inner-thread with Timer?

My goal is to save the power consumption as much as possible. Thanks.

Answer 1

I would recommend following

a) Use a Service. Activity is short lived entity (it works only while it's on the screen)

b) Make the service foreground (read this: http://developer.android.com/reference/android/app/Service.html#startForeground(int, android.app.Notification). This will decrease the chance that system will kill your service

c) In the service, start a thread and do everything you need in the thread.

d) If you want execute periodically, just do Thread.sleep() in the thread (when Thread sleeps it doesn't consume CPU cycles).

I believe c) and d) is preferable to AlarmManager. Here is piece from documentation (http://developer.android.com/reference/android/app/AlarmManager.html) : "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."

Since your application running it's better to have some permanently running thread and execute something on it. Generally speaking Handler, HandlerThread, MessageQueue are just convenience classes for more complex message handling and scheduling. It looks like your case is quite simple and usual Thread should be enough.