full screen application android

full screen application android

i have two questions:
one how can i run my application in full screen
how video players run videos in full screen.
i have tried alot and still struggling to achieve this but couldn't find a
solution.
the list of solution i found but they are not fulfilling my requirements
this hides only the notification bar.
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
also hides only the notification bar
android:label="@string/app_name"
android:theme="@android:style/Theme.NoTitleBar.Fullscreen">
note that:
i am not talking about rooting a device,so please provide those solutions
which can work without rooting a device.
i am not talking about hiding only notification bar,but full screen by
hiding both navigation bar and notification bar too.
i am talking about jelly beans api 4.1 or greater than 4.1 version of android
and please give answers with code.