Update, now that android 5 has been officially released and the google have fixed the bug I'd reported I've an update coming in the next few days to remove the persistent notification.
Why do I have a persistent icon linking to this blog?
Version 3.20.107 of Light Flow adds in compatibility for the Android L preview.At the moment there's a few issues, but versions prior to this cause a boot loop in android (ie shortly after the phone boot's it'll reboot with lightflow installed)
This seems to be an issue with L I've raised an issue on the android L issue tracker here: https://code.google.com/p/android-developer-preview/issues/detail?id=667
This can be "starred" to show you have this issue, but please don't comment unless you've something useful to add as every person who's starred the issue will get an email notification!
As for 3.20.107 there's a couple of things you'll notice
- You'll get an additional notification in the notification bar that has a persistent icon that can't be removed
- Cycling notifications is currently erratic
Find more details about these below
Additional notification
This persistent icon in the notification bar has been added to work around the reboot issue above. The LED's in android require a notification to be raised. These can't be low priority notification such as things like Google Now weather which only show in the notification shade when viewed. Each notification has a priority and only Normal, High and Max can show notifications which means showing it even when the notification bar isn't displayed. If set to Low or Min then the notification won't show.
Can anything be done about this?
Well, yes and no. Android L adds the concept of a secret notification which means it won't show on the lock screen which will help a little.
At the moment, this can't be added though as developers are not allowed to publish apps yet using the new features.
So why is there two notifications in the notification bar?
By default lightflow runs in foreground mode as it needs to always be running (similar to apps such as the new android wearable app) without this it'll end up missing some notifications.
I've tried to set the persistent foreground notification to control the LED but it seems very unreliable as it seems to have to stop and restart the notification to change it and if another app raises a notification in-between it'll take control of the LED and stop lightflow. I've put in a feature request to android to remove this (user selectable) and this can also be starred here: https://code.google.com/p/android-developer-preview/issues/detail?id=443
Cycling Notifications erractic
This is something I'm currently looking into but was keen to allow people to use the app with L so decided it was worth pushing out an update before this is fully resolved. Sometimes when cycling you'll get smooth changes, other times it'll look like there's not two notifications but just a flicker of the led. I'm not sure if this is part of the battery saving work going into L and batching up repeating operations. I'm still investigating this.
Hopefully by the time L becomes a consumer release these issues will have been resolved!