使用Pull解析器生成XML文件和读取xml文件

有些时候，我们需要生成一个XML文件，生成XML文件的方法有很多，如：可以只使用一个StringBuilder组拼XML内容，然后把内容写入到文件中；或者使用DOM API生成XML文件，或者也可以使用pull解析器生成XML文件，这里推荐大家使用Pull解析器。

一、布局界面

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <Button
        android:id="@+id/btn_pull"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="110dp"
        android:text="@string/btn_pull" />

    <Button
        android:id="@+id/btn_write"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/btn_pull"
        android:layout_alignRight="@+id/btn_pull"
        android:layout_below="@+id/btn_pull"
        android:layout_marginTop="61dp"
        android:text="@string/btn_write" />

</RelativeLayout>

二、写一个xml文件

<?xml version="1.0" encoding="UTF-8"?>
<persons>
    <person id="23">
        <name>李明</name>
        <age>30</age>
    </person>
    <person id="20">
        <name>李向梅</name>
        <age>25</age>
    </person>
</persons>

三、写一个和xml相对应的bean

package com.example.lession04_pull.domain;

import java.io.Serializable;

public class Person implements Serializable{

    /**
     *
     */
    private static final long serialVersionUID = 1L;
    private int id;
    private String name;
    private short 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 short getAge() {
        return age;
    }
    public void setAge(short age) {
        this.age = age;
    }
    public Person(int id, String name, short age) {
        super();
        this.id = id;
        this.name = name;
        this.age = age;
    }
    public Person() {
        super();
        // TODO Auto-generated constructor stub
    }


}

四、写一个Pul的服务类

package com.example.lession04_pull.service;

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

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlSerializer;
import android.os.Environment;
import android.util.Xml;

import com.example.lession04_pull.domain.Person;

public class PullXmlService {

    public Person currentPerson;

    public List<Person> readXml(InputStream is){
        //声明返回值
        List<Person> persons=null;
        //首先利用Xml.newPullParser()获取解析对象
        XmlPullParser xmlPullParser=Xml.newPullParser();
        try{
            // 解析文件
            xmlPullParser.setInput(is, "UTF-8");
            //获取解析的事件类型
            int eventType=xmlPullParser.getEventType();
            //判断文件解析的是否完毕
            while(eventType!=XmlPullParser.END_DOCUMENT){
                switch (eventType) {
                case XmlPullParser.START_DOCUMENT:
                    persons=new ArrayList<Person>();
                    break;

                case XmlPullParser.START_TAG:
                    String tagName=xmlPullParser.getName();
                    if("person".equals(tagName)){
                        //创建person对象
                        currentPerson=new Person();
                        currentPerson.setId(Integer.parseInt(xmlPullParser
                                .getAttributeValue(null, "id")));
                    }else if("name".equals(tagName)){
                        currentPerson.setName(xmlPullParser.nextText());
                    }else if("age".equals(tagName)){
                        currentPerson.setAge(new Short(xmlPullParser.nextText()));
                    }
                    break;
                case XmlPullParser.END_TAG:
                    if("person".equals(xmlPullParser.getName()) && currentPerson!=null){
                        //把person对象放到集合中去
                        persons.add(currentPerson);
                        currentPerson=null;
                    }
                    break;
                }
                eventType=xmlPullParser.next();
            }
            is.close();
        }catch(Exception e){
            e.printStackTrace();
        }
        return persons;
    }



    // 写入
        public boolean write(List<Person> persons) {
            // 采用pull解析进行实现

            if (Environment.getExternalStorageState().equals(
                    Environment.MEDIA_MOUNTED)) {

                // 获取sdcard目录 文件对象
                File sdCardDir = Environment.getExternalStorageDirectory();
                // 创建文件
                File file = new File(sdCardDir, "mycsdn.xml");

                XmlSerializer serializer = Xml.newSerializer();

                FileOutputStream fos = null;
                try {
                    // 根据文件对象创建一个文件的输出流对象
                    fos = new FileOutputStream(file);
                    // 设置输出的流及编码
                    serializer.setOutput(fos, "UTF-8");
                    // 设置文件的开始
                    serializer.startDocument("UTF-8", true);
                    // persons标签开始
                    serializer.startTag(null, "persons");
                    for (Person person : persons) {
                        // person标签的开始
                        serializer.startTag(null, "person");
                        // 设置person标签的属性
                        serializer.attribute("null", "id", person.getId() + "");

                        // 设置person标签的子标签 name
                        serializer.startTag(null, "name");
                        serializer.text(person.getName());
                        serializer.endTag(null, "name");

                        // 设置person标签的子标签的age
                        serializer.startTag(null, "age");
                        serializer.text(person.getAge() + "");
                        serializer.endTag(null, "age");

                        // person标签的结束
                        serializer.endTag(null, "person");
                    }

                    // persons标签的结束
                    serializer.endTag(null, "persons");
                    // 文件的结束
                    serializer.endDocument();

                    fos.flush();
                    fos.close();
                    return true;
                } catch (Exception e) {
                    e.printStackTrace();
                }

            }

            return false;
        }

}

五、在MainActivity中调用测试

package com.example.lession04_pull;

import java.util.List;

import com.example.lession04_pull.domain.Person;
import com.example.lession04_pull.service.PullXmlService;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends Activity {

    public Button btn_pull,btn_write;
    public PullXmlService pullXmlService;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //实例化
        pullXmlService=new PullXmlService();

        btn_pull=(Button) findViewById(R.id.btn_pull);
        btn_write=(Button) findViewById(R.id.btn_write);

        btn_pull.setOnClickListener(new MyOnClickListener());
        btn_write.setOnClickListener(new MyOnClickListener());
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    class MyOnClickListener implements View.OnClickListener{

        @Override
        public void onClick(View v) {
            int id=v.getId();
            switch (id) {
            case R.id.btn_pull:
                List<Person> persons=null;
                try{
                    persons=pullXmlService.readXml(getAssets().open("csdn.xml"));
                }catch(Exception e){
                    e.printStackTrace();
                }
                if(persons!=null){
                    Toast.makeText(MainActivity.this, "采用pull解析xml文件"+persons.get(0).getName()+"--"+persons.get(1).getName(),
                            Toast.LENGTH_LONG).show();
                }
                break;

            case R.id.btn_write:
                try{
                    List<Person> pers=pullXmlService.readXml(getAssets().open("csdn.xml"));
                    //重新生成一个xml文件  mysdcare.xml
                    boolean flag=pullXmlService.write(pers);
                    if(flag){
                        Toast.makeText(MainActivity.this, "采用pull解析生产xml文件成功",
                                Toast.LENGTH_LONG).show();
                    }else{
                        Toast.makeText(MainActivity.this, "采用pull解析生产xml文件失败",
                                Toast.LENGTH_LONG).show();

                    }
                }catch(Exception e){
                    e.printStackTrace();
                }
                break;
            }

        }

    }

}