Earlier these things would be possible only if you had rooted your Android smartphone.
While non-rooted users could use buttons only for functions assigned to them by the gear manufacturer.
Step 2 : Install Button Mapper App and initiate the Accessibility Plugin.
Here is how you do it.
Step 3 : Remap your Android buttons as you wish.
when you’ve got enabled Accessibility Plugin, head over back to the App.
Button Mappers fund doesnt end here.
It lets you assign a custom single tap or long press action for this button.
Once youve finished setting everything up, your hardware buttons will now have completely different functionalityall without requiring root.
Now you’re able to show your friends your newly assigned functions thanks to Segearts Button Mapper.
source: www.techworm.net