Android学习--使用Pull解析器读取XML文件、将对象写入XML文件

居然没有保存上，今天补上。。。

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

 <RelativeLayoutxmlns: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>

 <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

 <span style="color:#000000;">[html] view plaincopyprint?
 <?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> </span>

 <?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

 <span style="color:#000000;">[java] view plaincopyprint?
 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
 }


 } </span>

 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

 

 <span style="color:#000000;">[java] view plaincopyprint?
 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;
 }
 </span>

 

 }

 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

 [java] view plaincopyprint?
 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;
 }

 }

 }

 }