我有xml文件，我需要读取到加载级别。此文件位于assets文件夹中。当我在Destop机器上运行时，一切正常。但是在android设备上，当我试图解析这个文件时，我得到了filenotfoundexception。这是阅读方法的代码

public void readLevels() {

    this.levelList = new ArrayList<Level>();
    FileHandle handle = Gdx.files.internal("lvl/levels.xml");

    try {
        File fXmlFile =  handle.file();
        DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
        try {
            Document document = documentBuilder.parse(fXmlFile);

            document.getDocumentElement().normalize();

            NodeList nodeList = document.getElementsByTagName("level");

            Level level;

            for (int iterator = 0; iterator < nodeList.getLength(); iterator++) {
                Node node = nodeList.item(iterator);
                Element element = (Element) node;

                String levelName = element.getAttribute("name");
                int levelNumber = Integer.parseInt(element.getAttribute("order"));

                NodeList ballList = element.getElementsByTagName("ball");

                List<Ball> levelBallList = new ArrayList<Ball>();
                Ball ball;

                for (int iter = 0; iter < ballList.getLength(); iter++) {
                    Element ballIn = (Element) ballList.item(iter);

                    NodeList positionX = ballIn.getElementsByTagName("position-x");
                    NodeList positionY = ballIn.getElementsByTagName("position-y");

                    int x = Integer.parseInt(positionX.item(0).getChildNodes().item(0).getNodeValue());
                    int y = Integer.parseInt(positionY.item(0).getChildNodes().item(0).getNodeValue());

                    ball = new Ball(new Vector2(y, x), ballTextures[generateImage()]);
                    levelBallList.add(ball);
                }

                level = new Level(levelName, levelNumber, levelBallList);
                this.levelList.add(level);
            }

        } catch (SAXException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

    } catch (ParserConfigurationException e) {
        e.printStackTrace();
    }
}