SAX解析xml

<apps>
<app>
<id>1</id>
<name>Google Maps</name>
<version>1.0</version>
</app>
<app>
<id>2</id>
<name>Chrome</name>
<version>2.1</version>
</app>
<app>
<id>3</id>
<name>Google Play</name>
<version>2.3</version>
</app>
</apps>

package com.aotian.guo.saxxmldemo;

import android.util.Log;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

/**
 * Created by guo on 2017/4/24.
 */

public class MyContentHandler extends DefaultHandler {

    private StringBuilder id;
    private StringBuilder name;
    private StringBuilder version;
    private String nodeName;


    @Override
    public void startDocument() throws SAXException {
        id = new StringBuilder();
        name = new StringBuilder();
        version = new StringBuilder();
    }

    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes)
            throws SAXException {
        nodeName = localName;
    }

    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {
        if( "id".equals(nodeName) ){
            id.append(ch,start, length);
        }
        if( "name".equals(nodeName) ){
            name.append(ch,start,length);
        }
        if("version".equals(nodeName)){
            version.append(ch, start, length);
        }
    }

    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        if(localName.equals("app")){
            if("app".equals(localName)){
                Log.e("id", id.toString().trim());
                Log.e("name", name.toString().trim());
                Log.e("version", version.toString().trim());

                id.setLength(0);
                name.setLength(0);
                version.setLength(0);
            }
        }
    }

    @Override
    public void endDocument() throws SAXException {

    }
}

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        getXml();
    }

    private void getXml(){
        OkHttpClient http = new OkHttpClient();
        final Request request = new Request.Builder()
                .url("http://192.168.2.100:8001/a.xml")
                .build();

        Call call = http.newCall(request);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {

            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                parseXmlSax(response.body().string());
            }
        });
    }

    private void parseXmlSax(String xmldata){
        try {
            SAXParserFactory factory = SAXParserFactory.newInstance();
            XMLReader xmlReader = factory.newSAXParser().getXMLReader();
            MyContentHandler handler = new MyContentHandler();
            // 设置实例
            xmlReader.setContentHandler(handler);
            // 开始解析
            xmlReader.parse(new InputSource(new StringReader(xmldata)));
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}