隐藏底部虚拟导航栏

    public void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);                   window = getWindow();          WindowManager.LayoutParams params = window.getAttributes();          params.systemUiVisibility = View.SYSTEM_UI_FLAG_HIDE_NAVIGATION;          window.setAttributes(params);            setContentView(R.layout.main);      }