Scanning stops while backgrounded if no filters are provided

Hi there,

I’m trying to run Kable within a LifecycleService and collect advertisements while the device screen is off (sleeping).

I have to admit I’m having a hard time understanding how to perform this, though I’m able to run a custom Flow while the device screen is off, I can’t get the same success with a simple scan. It works while the app is in background but as soon as I shut the screen off or turn in back on, advertisements stop and start again.

val scanner = Scanner {}
scanner
.advertisements
.onEach { Log.i("TAG", "Scan advertisement => $it") }
.launchIn(lifecycleScope)

Here is a sample repo as an example
And the interesting part is here

Any help would be appreciated, Thanks!

[twyatt]

I believe this has been addressed, although the fix is not yet released (currently on the main branch).

Once the issues for 0.11.0 milestone have been resolved, then that release should have this fix.

[somq]

Your welcome! This behavior exists since Android 8.1. You can find some refs. here, and here is the culprit.

I’m not sure how you’d like to shape this info into the docs so I’ll let you do it.

EDIT: Some people are reporting that even an empty scanFilter is a workaround (for how long until patched?) though I did not test this by myself.
Therefore a quickfix might be an option?