Android 中使用SAX解析XML实例

1. SAX
 SAX, 即Simple API for XML的缩写，是一种事件驱动的用于解析XML的API。

 解析器是XMLReader，事件处理器是ContentHandler接口。

2. 实例说明

 下面是一个包含人员信息的XML，需要完成的功能是用SAX解析人员信息，然后在Android App中用ListView显示。

<?xml version="1.0" encoding="utf-8"?>
<persons>
<person id="20042782" name="leon" />
<person id="20042783" name="pepe" />
<person id="20042784" name="ozil" />
<person id="20042785" name="kaka" />
<person id="20042786" name="ronaldo" />
<person id="20042787" name="benzema" />
<person id="20042788" name="owen" />
<person id="20042789" name="beckham" />
<person id="20042790" name="figo" />
<person id="20042791" name="zidan" />
</persons>

实现步骤如下：

1）实现自己的事件处理器类SAXParseHandler，向外提供接口getData()，返回解析后的数据

package com.example.saxdemo.sax;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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

public class SAXParseHandler extends DefaultHandler {

    List<Map<String, Object>> list;
    HashMap<String, Object> item;
    
    public List<Map<String, Object>> getData(){
        return list;
    }
    
    @Override
    public void characters(char[] ch, int start, int length)
            throws SAXException {
        // TODO Auto-generated method stub
        super.characters(ch, start, length);
    }

    @Override
    public void endDocument() throws SAXException {
        // TODO Auto-generated method stub
        super.endDocument();
    }

    @Override
    public void endElement(String uri, String localName, String qName)
            throws SAXException {
        // TODO Auto-generated method stub
        super.endElement(uri, localName, qName);
        if (localName.equals("person")){
            list.add(item);
        }
    }

    @Override
    public void startDocument() throws SAXException {
        // TODO Auto-generated method stub
        super.startDocument();
        list = new ArrayList<Map<String, Object>>();
    }

    @Override
    public void startElement(String uri, String localName, String qName,
            Attributes attributes) throws SAXException {
        // TODO Auto-generated method stub
        super.startElement(uri, localName, qName, attributes);
        item = new HashMap<String, Object>();
        if (localName.equals("person")){
            for (int i=0; i<attributes.getLength(); i++){
                item.put(attributes.getLocalName(i), attributes.getValue(i));
            }
        }
    }

}

2) 在Activity中实现解析XML并得到ListView需要的数据的接口
   步骤：实例化一个SAXParseFactory --> 实例化SAXParser对象 --> 实例化事件处理器 --> 为XMLReader解析器注册一个事件处理器 --> 获取需要解析的XML文件的文件流 --> 开始解析XMLReader.parse()

List<Map<String, Object>> getData() throws ParserConfigurationException, SAXException, IOException{
        SAXParserFactory saxParserFactory = SAXParserFactory.newInstance();
        SAXParser saxParser = saxParserFactory.newSAXParser();
        XMLReader xmlReader = saxParser.getXMLReader();
        SAXParseHandler saxParseHandler = new SAXParseHandler();
        xmlReader.setContentHandler(saxParseHandler);
        
        InputStream inputStream = getResources().openRawResource(R.raw.persons);
        xmlReader.parse(new InputSource(inputStream));
        return saxParseHandler.getData();
    }

3) 用SimpleAdapter装载ListView

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        parseBtn = (Button) findViewById(R.id.button1);
        listView = (ListView) findViewById(R.id.listView1);
        
        parseBtn.setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                SimpleAdapter adapter = null;
                try {
                    adapter = new SimpleAdapter(MainActivity.this, getData(), R.layout.person,
                            new String[]{"name", "id"}, 
                            new int[]{R.id.person_name, R.id.person_id});
                    listView.setAdapter(adapter);
                } catch (ParserConfigurationException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (SAXException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        });
    }

3. 运行效果

点击"Parse By SAX" 按钮时，会把XML中的数据显示到ListView上。