xml的serializer使用

//最后两个实现的方作用是一样的
package com.itheima.xmlseralizer;

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;

import javax.xml.XMLConstants;

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

import android.app.Activity;
import android.os.Bundle;
import android.util.Xml;
import android.view.View;

public class MainActivity extends Activity {
    ArrayList<SMS> smsList = new ArrayList<SMS>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        for(int i = 0;i<30;i++){
            SMS sms = new SMS();
            sms.from= "10000"+i;
            sms.content="content"+i;
            sms.time="2016-9-4 16:25:"+i;
            smsList.add(sms);
        }
        
        for(SMS sms: smsList){
            System.out.println(sms);
        }
        
    }


    public void saveSMS(View v){
        StringBuilder sb = new StringBuilder();
        //写xml的文档声明
        sb.append("<?xml version=\"1.0\" encoding=\"utf-8\"?>");
        sb.append("<SMSList>");
        for(SMS sms:smsList){
            //写每一个sms开始的标签
            sb.append("<SMS>");
            
            //一个属性一个属性写对应的节点
            sb.append("<from>");
            sb.append(sms.from);
            sb.append("</from>");
            
            sb.append("<content>");
            sb.append(sms.content);
            sb.append("</content>");
            
            sb.append("<time>");
            sb.append(sms.time);
            sb.append("</time>");
            
            sb.append("</SMS>");
        }
        sb.append("</SMSList>");
        
        String xml = sb.toString();
        try {
            FileOutputStream fos = openFileOutput("sms.xml", MODE_PRIVATE);
            fos.write(xml.getBytes());
            fos.close();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
  
    public void saveSMS2(View v){
        //获取xml序列化器
        XmlSerializer serializer = Xml.newSerializer();
        //给序列化器设置一个输出
        try {
            serializer.setOutput(openFileOutput("smslist.xml", MODE_PRIVATE), "utf-8");
            //写文档开始的声明<?xml version="1.0"?>
            serializer.startDocument("utf-8", true);
            //第一个参数 名称空间 如果当前文档受某份schema约束就传入一个名称空间 没有约束的情况传null
            //<SMSList>
            serializer.startTag(null, "SMSList");
            for(SMS sms:smsList){
                //写<SMS>
                serializer.startTag(null, "SMS");
                
                serializer.startTag(null, "from");
                serializer.text(sms.from);
                serializer.endTag(null, "from");
                
                serializer.startTag(null, "content");
                serializer.text(sms.content);
                serializer.endTag(null, "content");
                
                serializer.startTag(null, "time");
                serializer.text(sms.time);
                serializer.endTag(null, "time");
                
                //</SMS>
                serializer.endTag(null, "SMS");
            }
            
            //</SMSList>
            serializer.endTag(null, "SMSList");
            serializer.endDocument();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }