PopupWindow在全屏显示时，弹出导致导航栏唤出

转载自：https://blog.youkuaiyun.com/dingdewei113/article/details/106407996

解决如下：

当PopupWindow设置了setFcousable属性后，会导致导航栏唤出

private static final int FULL_SCREEN_FLAG =
			View.SYSTEM_UI_FLAG_LAYOUT_STABLE
            | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
            | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
            | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
            | View.SYSTEM_UI_FLAG_FULLSCREEN;

popupWindow.setFocusable(false);
popupWindow.showAtLocation(view,  x,  y);
popupWindow.getContentView().setSystemUiVisibility(FULL_SCREEN_FLAG);
popupWindow.setFocusable(true);
popupWindow.update();