android:fontFamily="sans-serif"// roboto regular
android:fontFamily="sans-serif-light"// roboto light
android:fontFamily="sans-serif-condensed"// roboto condensed
android:fontFamily="sans-serif-black"// roboto black
android:fontFamily="sans-serif-thin"// roboto thin (android 4.2)
android:fontFamily="sans-serif-medium"// roboto medium (android 5.0)
