SAX解析android：如何获取子节点

我想从XML文件获取数据：https : //www.vietcombank.com.vn/exchangerates/ExrateXML.aspx

错误是我可以获取最后一个元素USD并传递其他元素。请帮我

这是我所有的课程：Exrate.java

 public class Exrate {
    String CurrencyCode;
    String CurrencyName;
    String Buy;
    String Transfer;
    String Sell;

    public Exrate(){}

    public String getCurrencyCode() {
        return CurrencyCode;
    }
    public void setCurrencyCode(String CurrencyCode) {
        this.CurrencyCode = CurrencyCode;
    }
    //
    public String getCurrencyName(){
        return CurrencyName;
    }
    public void setCurrencyName(String CurrencyName){
        this.CurrencyName=CurrencyName;
    }
    //
    public String getBuy(){
        return Buy;
    }
    public void setBuy(String Buy ){
        this.Buy=Buy;
    }
    //
    public String getTransfer(){
        return Transfer;
    }
    public void setTransfer(String Transfer ){
        this.Transfer=Transfer;
    }
    //
    public String getSell(){
        return Sell;
    }
    public void setSell(String Sell ){
        this.Sell=Sell;
    }
}

ExrateList.java

    public class ExrateList {
    String Datetime;
    Exrate exrate;
    public ExrateList(){}

    public String getDatetime(){
        return Datetime;
    }
    public void setDatetime(String DateTime){
        this.Datetime=DateTime;
    }
    //
    public Exrate getExrate(){
        return exrate;
    }
    public void setExrate(Exrate exrate){
        this.exrate=exrate;
    }

}

SaxHandler.java

    public class SaxHandler extends DefaultHandler {

    String reading;
    ArrayList<ExrateList> exrateLists;
    ExrateList exrateList;
    Exrate exrate;
    public SaxHandler() {
        exrateLists = new ArrayList<ExrateList>();
    }



    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
        if (qName.equalsIgnoreCase("ExrateList")){
                exrateLists=new ArrayList<>();
                exrateList=new ExrateList();
        }
        if (qName.equalsIgnoreCase("Exrate")){
            exrate=new Exrate();
            exrate.setCurrencyCode(attributes.getValue("CurrencyCode"));
            exrate.setCurrencyName(attributes.getValue("CurrencyName"));
            exrate.setBuy(attributes.getValue("Buy"));
            exrate.setTransfer(attributes.getValue("Transfer"));
            exrate.setSell(attributes.getValue("Sell"));
        }
    }

    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        if (qName.equalsIgnoreCase("ExrateList")){
            if (exrateLists!=null){
                exrateLists.add(exrateList);
                exrateList=null;
            }
        }
         if (qName.equalsIgnoreCase("DateTime")){
            exrateList.setDatetime(reading);
        }
        else if (qName.equalsIgnoreCase("Exrate")){
            exrateList.setExrate(exrate);

        }
    }

    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {
        reading=new String(ch, start, length);
    }

    public List<ExrateList> getExrateLists() {
        return exrateLists;
    }
}

MySaxParser.java

    public class MySaxParser {
    public List<ExrateList> XMLparse(InputStream is) {
        List<ExrateList> exrateLists = null;
        try {
            // create a XMLReader from SAXParser
            XMLReader xmlReader = SAXParserFactory.newInstance().newSAXParser().getXMLReader();
            // create a SAXXMLHandler
            SaxHandler saxHandler = new SaxHandler();
            // store handler in XMLReader
            xmlReader.setContentHandler(saxHandler);
            // the process starts
            xmlReader.parse(new InputSource(is));
            // get the `Employee list`
            exrateLists =saxHandler.getExrateLists();

        } catch (Exception ex) {
            Log.d("XML", "SAXXMLParser: parse() failed");
        }

        // return Employee list
        return exrateLists;
    }
}

MainActivity.java

    public class MainActivity extends AppCompatActivity {
    TextView ngay, chuoi;
    String duongdan = "https://www.vietcombank.com.vn/exchangerates/ExrateXML.aspx";
    List<ExrateList> exrateLists = new ArrayList<ExrateList>();
    String datetime;
    String macode="";
    String tencode="";
    String mua="";
    InputStream is;
    URL url;
    URLConnection connection;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ngay = (TextView) findViewById(R.id.textView);
        chuoi = (TextView) findViewById(R.id.textView2);
        Task a=new Task();
        a.execute();
    }

    class Task extends AsyncTask<Void,Void,Void>
    {
        @Override
        protected Void doInBackground(Void... params) {
            try {
                url=new URL(duongdan);
                connection=url.openConnection();
                is=connection.getInputStream();
                MySaxParser mySaxParser=new MySaxParser();
                exrateLists=mySaxParser.XMLparse(is);
                //
                datetime=exrateLists.get(0).getDatetime();

                for(int i=0;i<exrateLists.size();i++) {

                    macode+=exrateLists.get(i).getExrate().getCurrencyCode();
                    tencode+= exrateLists.get(i).getExrate().getCurrencyName()+"\n";
                    mua+= exrateLists.get(i).getExrate().getBuy();

                }


            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(Void aVoid) {
            super.onPostExecute(aVoid);
            ngay.setText(datetime);
            chuoi.setText(macode+" "+tencode+" "+mua);

        }
    }

}