//分三部分1是得到实体类.2是得到干活的类personservice.3是在主活动调用干活的类做输出.

package cn.itcast.xml.domain;

public class Person {
	private int id;
	private String name;
	private int age;

	public Person(){
		
	}
	
	
	public Person(int id,String name,int age) {
		this.id = id;
		this.name = name;
		this.setAge(age);
	}

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		if (age > 0 && age < 100) {
			this.age = age;
		}else{
			this.age = 0;
		}

	}

}

<pre class="java" name="code">package cn.itcast.xml.service;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlSerializer;

import android.content.Context;
import android.content.res.AssetManager;
import android.os.Environment;
import android.util.Xml;
import android.widget.Toast;

import cn.itcast.xml.domain.Person;

public class PersonService {
	private Context context;
	
	public PersonService(Context context) {
		this.context = context;
	}

	/**
	 * 把person.xml的输入流 解析 转化成list集合 
	 * @param filename  assets目录下的文件名 
	 * @return
	 */
	public List<Person> getPersons(String filename){
		AssetManager manager = context.getAssets();
		try {
			InputStream  is = manager.open(filename);
			//在android下使用pull解析xml文件 
			//1.获取pull解析器的实例
			XmlPullParser  parser = Xml.newPullParser();
			//2.设置解析器的一些参数 
			parser.setInput(is,"utf-8");
			// 获取pull解析器对应的事件类型 
			int type = parser.getEventType();
			Person person = null;
			List<Person> persons = new ArrayList<Person>();
			while(type!=XmlPullParser.END_DOCUMENT){
	
				if(type==XmlPullParser.START_TAG){
					if("person".equals(parser.getName())){
						person = new Person();
						int id =Integer.parseInt( parser.getAttributeValue(0));
						person.setId(id);
					}else if("name".equals(parser.getName())){
						String name = parser.nextText();
						person.setName(name);
					}else if("age".equals(parser.getName())){
						int age = Integer.parseInt( parser.nextText());
						person.setAge(age);
					}
				}
				if(type==XmlPullParser.END_TAG){
					if("person".equals(parser.getName())){
						persons.add(person);
						person = null;
					}
				}
				
				
				 type = parser.next();
			}
			
			return persons;
			
			
		} catch (Exception e) {
			e.printStackTrace();
			Toast.makeText(context,"获取person.xml失败",Toast.LENGTH_SHORT).show();
			return null;
		}
	}
	
	/**
	 * 把persons集合里面的内容写到xml文件里面 
	 * @param persons person的集合
	 * @return
	 */
	public boolean savePersonToXml(List<Person> persons){
		try {
			XmlSerializer  serializer =  Xml.newSerializer();
			// /sdcard/person.xml 
			// mount unmount 文件系统的权限 
			File file = new File(Environment.getExternalStorageDirectory(),"person.xml");
			FileOutputStream fos = new FileOutputStream(file);
			serializer.setOutput(fos,"utf-8");
			serializer.startDocument("utf-8",true);
			serializer.startTag(null,"persons");
			for(Person person:persons){
				serializer.startTag(null,"person");
				
				serializer.attribute(null,"id",person.getId()+"");
				
				serializer.startTag(null,"name");
				serializer.text(person.getName());
				serializer.endTag(null,"name");
				
				serializer.startTag(null,"age");
				serializer.text(person.getAge()+"");
				serializer.endTag(null,"age");
				
				
				serializer.endTag(null,"person");
			}
			serializer.endTag(null,"persons");
			serializer.endDocument();
			fos.flush();
			fos.close();
			return true;
		} catch (Exception e) {
			e.printStackTrace();
			return false;
		}
		

	}
	
}

<pre class="java" name="code">package cn.itcast.xml;

import java.util.List;

import cn.itcast.xml.domain.Person;
import cn.itcast.xml.service.PersonService;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class MainActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        TextView tv = (TextView) this.findViewById(R.id.tv);
        PersonService service = new PersonService(this);
        List<Person> persons = service.getPersons("person.xml");
        StringBuffer sb = new StringBuffer();
        for(Person person : persons){
        	String age = "年龄"+ person.getAge();
        	String name  =person.getName();
        	String id = "id="+ person.getId();
        	sb.append(name +" "+ age+" "+id);
        }
        tv.setText( sb.toString());
    }
}

package cn.itcast.xml.test;

import java.util.ArrayList;
import java.util.List;

import cn.itcast.xml.domain.Person;
import cn.itcast.xml.service.PersonService;
import android.test.AndroidTestCase;
import android.util.Log;

public class TestPersonService extends AndroidTestCase {
	
	private static final String TAG = "TestPersonService";

	public void testGetPersons() throws Exception{
		PersonService service = new PersonService(getContext());
		List<Person> persons = service.getPersons("person.xml");
		assertEquals(2,persons.size());
		Log.i(TAG,persons.get(0).getName());
	}
	
	
	public void testSavePersons() throws Exception{
		PersonService service = new PersonService(getContext());
		List<Person> persons = new ArrayList<Person>();
		Person p1 = new Person(21,"张三",18);
		Person p2 = new Person(27,"李四",29);
		Person p3 = new Person(29,"wangwu",-3);
		persons.add(p1);
		persons.add(p2);
		persons.add(p3);
		assertEquals(true,service.savePersonToXml(persons)) ;
		
	}
}