* SYSTEM_UI_FLAG_FULLSCREEN hides the status bar at the top of the screen.
* SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN makes the root frame layout fill the area that is normally reserved for the status bar.
* SYSTEM_UI_FLAG_HIDE_NAVIGATION hides the navigation bar on the bottom or right of the screen.
* SYSTEM_UI_FLAG_FULLSCREEN hides the status bar at the top of the screen.
* SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN makes the root frame layout fill the area that is normally reserved for the status bar.
* SYSTEM_UI_FLAG_HIDE_NAVIGATION hides the navigation bar on the bottom or right of the screen.