Android 4.0 phones only have virtual buttons, which actually go invisible when playing youtube/video at fullscreen (the video portion takes over where the buttons are).
I want to do this, but haven't found a way.
android:theme="@android:style/Theme.NoTitleBar.Fullscreen"
or
requestWindowFeature(Window.FEATURE_NO_TITLE);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
do not cover the virtual buttons.
Here is an example that shows the type of full screen I'm talking about: