Not really a button rather the proximity sensor for some apps. You can use trickdtr too
Also there are init.d scripts you can use if the kernel supports it. But again to my earlier point, expect needless battery drain for a somewhat gimicky feature. But if you like it there are options if you search
Sent from my Nexus 7 using XDA Premium 4 mobile app
Last edited by demkantor; 17th February 2014 at 04:55 AM.