3-button headsets: how to set the +/- buttons to something useful (e.g. track change) in Lollipop+ ?
On my Samsung Galaxy Note 3 under stock (rooted) KitKit - which has performed brilliantly for years by the way - I configured the headset '+' and '-' buttons for changing media tracks (and double-click to change albums) rather than the rather pointless and stupid default Samsung mode of merely duplicating the volume buttons that are already present on the phone. This was very easily done by making a couple of minor edits to the plain-text file /system/usr/keylayout/generic.kl .
I've now upgraded my device to Lollipop (I didn't really want to as I'm not a fan of Material Design, but some of my apps no longer support Android 4.x) but this tweak no longer works. Well, I can change the headset +/- button functions to MEDIA_NEXT and MEDIA_PREVIOUS as required, but doing so also changes the action of the hardware volume keys on the phone itself, which was most definitely not the intention! A number of apps in the Play Store which are meant to achieve this result (Headset Button Controller, Jays, Degauss, etc) also fail under Samsung Lollipop+. I tried a Marshmallow ROM too, same result.
Could someone let me know how to achieve this simple task of separating the functions of the headset +/- buttons from the device Vol+/Vol- keys, which was so easy in KitKit? Thanks.