Question about Apps and Battery Usage

[johnmcd348]

OK, new Droid user again and have a question about how the Apps affect Battery usage. I'm using a Note 2 with the latest OS.

So, I wanted to know if the apps are still using battery power when I switch screens? When I press the center (home) button, it shows me thumbnail list of all the apps, areas I've been to or used. I can select and remove them from the list. I am wondering if they are still using battery power until I remove them from the list. If this does tend to use extra battery power, is there an app out there that will definitely turn off the app when I am not using it?

I just don't know how Android manages Memory/power. It just seems that I can watch my battery power decrease, even when it's not being used.

Thanks

 

[johnmcd348]

Is there possibly a thread that's already addressed this that might not have come up with a search? Over 200 views and no answers, I can't believe there's not people here that have an answer, or at least an understanding of hos this all works.

Thanks

 

[B. Diddy]

This article explains how Android handles multitasking:
http://android-developers.blogspot.com/2010/04/multitasking-android-way.html

It doesn't specifically address your question about battery use, but I think it's safe to say that if an app is not using any CPU cycles, it isn't using battery. When you switch away from most apps, their processes will be put on hold (unless it requires an active service like playing music or syncing), which means they're not using CPU cycles and therefore not using battery. The tricky thing is figuring out if a given app is in fact requiring an active service.

In regard to the Recent Apps list (the icon next to the home button)--swiping a thumbnail away does not force close the app. This is only a list showing you what your recently used apps are, not what apps are opened or closed. This can most easily be demonstrated by playing music with an app like Pandora, then swiping that thumbnail away. If it actually force closed Pandora, the music would stop, but it doesn't.



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