question: registers a callback , to be triggered when the system ui visibility changes . concode_field_sep OnVisibilityChangeListener mOnVisibilityChangeListener concode_elem_sep int FLAG_LAYOUT_IN_SCREEN_OLDER_DEVICES concode_elem_sep View mAnchorView concode_elem_sep Activity mActivity concode_elem_sep int FLAG_FULLSCREEN concode_elem_sep int mFlags concode_elem_sep OnVisibilityChangeListener sDummyListener concode_elem_sep int FLAG_HIDE_NAVIGATION concode_field_sep void hide concode_elem_sep void show concode_elem_sep void setup concode_elem_sep void toggle concode_elem_sep SystemUiHider getInstance concode_elem_sep boolean isVisible concode_elem_sep void onVisibilityChange concode_elem_sep void onVisibilityChange
target: void function ( OnVisibilityChangeListener arg0 ) { if ( arg0 == null ) { arg0 = sDummyListener ; } mOnVisibilityChangeListener = arg0 ; }