Value: 4
Flag for View.SystemUiVisibility: View has requested to go into the normal fullscreen mode so that its content can take over the screen while still allowing the user to interact with the application.
This has the same visual effect as WindowManagerLayoutParams.FLAG_FULLSCREEN, meaning that non-critical screen decorations (such as the status bar) will be hidden while the user is in the View's window, focusing the experience on that content. Unlike the window flag, if you are using ActionBar in overlay mode with Window.FEATURE_ACTION_BAR_OVERLAY, then enabling this flag will also hide the action bar.
This approach to going fullscreen is best used over the window flag when it is a transient state -- that is, the application does this at certain points in its user interaction where it wants to allow the user to focus on content, but not as a continuous state. For situations where the application would like to simply stay full screen the entire time (such as a game that wants to take over the screen), the WindowManagerLayoutParams.FLAG_FULLSCREEN is usually a better approach. The state set here will be removed by the system in various situations (such as the user moving to another application) like the other system UI states.
When using this flag, the application should provide some easy facility for the user to go out of it. A common example would be in an e-book reader, where tapping on the screen brings back whatever screen and UI decorations that had been hidden while the user was immersed in reading the book.