设置 Acitivity 所在 window 的属性    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        if (VERSION.SDK_INT >= VERSION_CODES.KITKAT) {            getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);            getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);        }        setContentView(R.layout.activity_main);    }