Please see if you like my Changes 

I have made these 2 changes:-

-Added brightness setter

-Added Preferences icon in Action Bar 

Action bar shortcut is added because of fast and easy access to preferences since its used frequently.Also the developer.android website mentioned Pictures are faster than words & all android devices with version > 3.0 have action bar. 

For  Brightness setter , well it can have uses like say your device has low battery and you want to long last your device flash light as much as possible then this may come in handy.