Android中创建与几种解析xml的方法!

 

首先是创建，我们用XmlSerializer这个类来创建一个xml文件，其次是解析xml文件，常用的有dom,sax,XmlPullParser等方法，由于sax代码有点复杂，本节只讲解一下dom与XmlPullParser解析，至于几种解析xml的优缺点我就不再讲述了。

为了方便理解，我做了一个简单的Demo。首先首界面有三个按钮，点击第一个按钮会在sdcard目录下创建一个books.xml文件,另外两个按钮分别是调用dom与XmlPullParser方法解析xml文件，并将结果显示在一个TextView里。大家可以按照我的步骤一步步来:

第一步:新建一个Android工程,命名为XmlDemo.

第二步:修改main.xml布局文件，代码如下:

 

<? xml version ="1.0" encoding ="utf-8" ?>
< LinearLayout xmlns:android ="http://schemas.android.com/apk/res/android"
         android:orientation ="vertical"
         android:layout_width ="fill_parent"
         android:layout_height ="fill_parent"
         >
   < Button
     android:id ="@+id/btn1"
     android:layout_width ="fill_parent"    
         android:layout_height ="wrap_content"    
         android:text ="创建XML文件"
   />
   < Button
     android:id ="@+id/btn2"
     android:layout_width ="fill_parent"    
         android:layout_height ="wrap_content"    
         android:text ="DOM解析XML"
   />
   < Button
     android:id ="@+id/btn3"
     android:layout_width ="fill_parent"    
         android:layout_height ="wrap_content"    
         android:text ="XmlPullParse解析XML"
   />
   < TextView
     android:id ="@+id/result"
     android:layout_width ="fill_parent"    
         android:layout_height ="wrap_content"    
   />
</ LinearLayout >

 

 

第三步:修改主核心程序XmlDemo.java,代码如下:

 

 

package com.tutor.xml;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlPullParserFactory;
import org.xmlpull.v1.XmlSerializer;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.util.Xml;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class XmlDemo extends Activity implements OnClickListener {
        
   private static final String BOOKS_PATH = "/sdcard/books.xml";
   private Button mButton1,mButton2,mButton3;
   private TextView mTextView;
        @Override
         public void onCreate(Bundle savedInstanceState) {
                 super.onCreate(savedInstanceState);
                setContentView(R.layout.main);
                setupViews();
        }
         //初始化工作
         private void setupViews(){
          mTextView = (TextView)findViewById(R.id.result);
          mButton1 = (Button)findViewById(R.id.btn1);
          mButton2 = (Button)findViewById(R.id.btn2);
          mButton3 = (Button)findViewById(R.id.btn3);
          mButton1.setOnClickListener( this);
          mButton2.setOnClickListener( this);
          mButton3.setOnClickListener( this);
        }
         //创建xml文件
         private void createXmlFile(){
          File linceseFile = new File(BOOKS_PATH);
           try{
            linceseFile.createNewFile();
          } catch (IOException e) {
            Log.e( "IOException", "exception in createNewFile() method");
    }
          FileOutputStream fileos = null;
           try{
            fileos = new FileOutputStream(linceseFile);
          } catch (FileNotFoundException    e) {
            Log.e( "FileNotFoundException", "can't create FileOutputStream");
    }
          XmlSerializer serializer = Xml.newSerializer();
           try {
                        serializer.setOutput(fileos, "UTF-8");
                        serializer.startDocument( null, true);
                        serializer.startTag( null, "books");
                         for( int i = 0; i < 3; i ++){
                                serializer.startTag( null, "book");
                                serializer.startTag( null, "bookname");
                                serializer.text( "Android教程" + i);
                                serializer.endTag( null, "bookname");
                                serializer.startTag( null, "bookauthor");
                                serializer.text( "Frankie" + i);
                                serializer.endTag( null, "bookauthor");
                                serializer.endTag( null, "book");
                        }
                
                        serializer.endTag( null, "books");
                        serializer.endDocument();
                        serializer.flush();
                        fileos.close();
                } catch (Exception e) {
                  Log.e( "Exception", "error occurred while creating xml file");
                }
                Toast.makeText(getApplicationContext(), "创建xml文件成功!", Toast.LENGTH_SHORT).show();
        }
         //dom解析xml文件
         private void domParseXML(){
          File file = new File(BOOKS_PATH);
          DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();        
          DocumentBuilder db = null;    
           try {
      db = dbf.newDocumentBuilder();
    } catch (ParserConfigurationException e) {
      e.printStackTrace();
    }
    Document doc = null;
     try {
      doc = db.parse(file);
    } catch (SAXException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
    Element root = doc.getDocumentElement();
    NodeList books = root.getElementsByTagName( "book");
    String res = "本结果是通过dom解析:" + "/n";
     for( int i = 0; i < books.getLength();i++){
      Element book = (Element)books.item(i);
      Element bookname = (Element)book.getElementsByTagName( "bookname").item(0);
      Element bookauthor = (Element)book.getElementsByTagName( "bookauthor").item(0);
      res += "书名: " + bookname.getFirstChild().getNodeValue() + " " +
                     "作者: " + bookauthor.getFirstChild().getNodeValue() + "/n";
    }
    
    mTextView.setText(res);
        }
    
         //xmlPullParser解析xml文件
         private void xmlPullParseXML(){
          String res = "本结果是通过XmlPullParse解析:" + "/n";
           try {            
      XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
      XmlPullParser xmlPullParser = factory.newPullParser();
        
      xmlPullParser.setInput(Thread.currentThread().getContextClassLoader()
          .getResourceAsStream(BOOKS_PATH), "UTF-8");
        
       int eventType = xmlPullParser.getEventType();
        
       try{
         while (eventType != XmlPullParser.END_DOCUMENT) {
          String nodeName = xmlPullParser.getName();
           switch (eventType) {
           case XmlPullParser.START_TAG:
             if( "bookname".equals(nodeName)){    
              res += "书名: " + xmlPullParser.nextText() + " ";            
            } else if( "bookauthor".equals(nodeName)){
              res += "作者: " + xmlPullParser.nextText() + "/n";
            }
             break;
           default:
             break;
          }
          eventType = xmlPullParser.next();
        }
      } catch (IOException e) {
        e.printStackTrace();
      }    
    } catch (XmlPullParserException e) {
      e.printStackTrace();
    }
    
    mTextView.setText(res);
        }
         //按钮事件响应
   public void onClick(View v) {
     if(v == mButton1){
      createXmlFile();
    } else if(v == mButton2){
      domParseXML();        
    } else if(v == mButton3){
      xmlPullParseXML();
    }
  }    
}

 

 

第四步:由于我们在Sd卡上新建了文件，需要增加权限，如下代码(第16行):

 

 

<? xml version ="1.0" encoding ="utf-8" ?>
< manifest xmlns:android ="http://schemas.android.com/apk/res/android"
package ="com.tutor.xml"
android:versionCode ="1"
android:versionName ="1.0" >
< application android:icon ="@drawable/icon" android:label ="@string/app_name" >
< activity android:name =".XmlDemo"
android:label ="@string/app_name" >
< intent-filter >
< action android:name ="android.intent.action.MAIN" />
< category android:name ="android.intent.category.LAUNCHER" />
</ intent-filter >
</ activity >
</ application >
< uses-sdk android:minSdkVersion ="7" />
< uses-permission android:name ="android.permission.WRITE_EXTERNAL_STORAGE" />
</ manifest >

 

 

 

第五步:运行上述工程，查看效果:

启动首界面:

点击创建XML文件按钮,生成books.xml文件

books.xml内容如下:

<?xml version='1.0' encoding='UTF-8' standalone='yes' ?>
<books>
<book>
<bookname>Android教程0</bookname>
<bookauthor>Frankie0</bookauthor>
</book>
<book>
<bookname>Android教程1</bookname>
<bookauthor>Frankie1</bookauthor>
</book>
<book>
<bookname>Android教程2</bookname>
<bookauthor>Frankie2</bookauthor>
</book>
</books>

<?xml version='1.0' encoding='UTF-8' standalone='yes' ?> <books> <book> <bookname>Android教程0</bookname> <bookauthor>Frankie0</bookauthor> </book> <book> <bookname>Android教程1</bookname> <bookauthor>Frankie1</bookauthor> </book> <book> <bookname>Android教程2</bookname> <bookauthor>Frankie2</bookauthor> </book> </books>

点击DOM解析XML按钮:

点击XmlPullParse解析XML按钮:

 

 

http://blog.csdn.net/android_tutor/article/details/5890835

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