Android 中创建与解析XML的方法

大家好今天我今天给大家讲解一下android中xml的创建以及一些解析xml的常用方法。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，sax我将会在下一节单独讲解,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:

01 <?xml version="1.0" encoding="utf-8"?>
02 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
03 android:orientation="vertical"
04 android:layout_width="fill_parent"
05 android:layout_height="fill_parent"
06 >
07 <Button
08 android:id="@+id/btn1"
09 android:layout_width="fill_parent"
10 android:layout_height="wrap_content"
11 android:text="创建XML文件"
12 />
13 <Button
14 android:id="@+id/btn2"
15 android:layout_width="fill_parent"
16 android:layout_height="wrap_content"
17 android:text="DOM解析XML"
18 />
19 <Button
20 android:id="@+id/btn3"
21 android:layout_width="fill_parent"
22 android:layout_height="wrap_content"
23 android:text="XmlPullParse解析XML"
24 />
25 <TextView
26 android:id="@+id/result"
27 android:layout_width="fill_parent"
28 android:layout_height="wrap_content"
29 />
30 </LinearLayout>

第三步:修改主核心程序XmlDemo.java,代码如下:

001 package com.tutor.xml;
002 import java.io.File;
003 import java.io.FileNotFoundException;
004 import java.io.FileOutputStream;
005 import java.io.IOException;
006 import javax.xml.parsers.DocumentBuilder;
007 import javax.xml.parsers.DocumentBuilderFactory;
008 import javax.xml.parsers.ParserConfigurationException;
009 import org.w3c.dom.Document;
010 import org.w3c.dom.Element;
011 import org.w3c.dom.NodeList;
012 import org.xml.sax.SAXException;
013 import org.xmlpull.v1.XmlPullParser;
014 import org.xmlpull.v1.XmlPullParserException;
015 import org.xmlpull.v1.XmlPullParserFactory;
016 import org.xmlpull.v1.XmlSerializer;
017 import android.app.Activity;
018 import android.os.Bundle;
019 import android.util.Log;
020 import android.util.Xml;
021 import android.view.View;
022 import android.view.View.OnClickListener;
023 import android.widget.Button;
024 import android.widget.TextView;
025 import android.widget.Toast;
026 public class XmlDemo extends Activity implements OnClickListener {
027
028 private static final String BOOKS_PATH = "/sdcard/books.xml";
029 private Button mButton1,mButton2,mButton3;
030 private TextView mTextView;
031 @Override
032 public void onCreate(Bundle savedInstanceState) {
033 super.onCreate(savedInstanceState);
034 setContentView(R.layout.main);
035 setupViews();
036 }
037 //初始化工作
038 private void setupViews(){
039 mTextView = (TextView)findViewById(R.id.result);
040 mButton1 = (Button)findViewById(R.id.btn1);
041 mButton2 = (Button)findViewById(R.id.btn2);
042 mButton3 = (Button)findViewById(R.id.btn3);
043 mButton1.setOnClickListener(this);
044 mButton2.setOnClickListener(this);
045 mButton3.setOnClickListener(this);
046 }
047 //创建xml文件
048 private void createXmlFile(){
049 File linceseFile = new File(BOOKS_PATH);
050 try{
051 linceseFile.createNewFile();
052 }catch (IOException e) {
053 Log.e("IOException", "exception in createNewFile() method");
054 }
055 FileOutputStream fileos = null;
056 try{
057 fileos = new FileOutputStream(linceseFile);
058 }catch (FileNotFoundException e) {
059 Log.e("FileNotFoundException", "can't create FileOutputStream");
060 }
061 XmlSerializer serializer = Xml.newSerializer();
062 try {
063 serializer.setOutput(fileos,"UTF-8");
064 serializer.startDocument(null, true);
065 serializer.startTag(null, "books");
066 for(int i = 0; i < 3; i ++){
067 serializer.startTag(null, "book");
068 serializer.startTag(null, "bookname");
069 serializer.text("Android教程" + i);
070 serializer.endTag(null, "bookname");
071 serializer.startTag(null, "bookauthor");
072 serializer.text("Frankie" + i);
073 serializer.endTag(null, "bookauthor");
074 serializer.endTag(null, "book");
075 }
076
077 serializer.endTag(null, "books");
078 serializer.endDocument();
079 serializer.flush();
080 fileos.close();
081 } catch (Exception e) {
082 Log.e("Exception","error occurred while creating xml file");
083 }
084 Toast.makeText(getApplicationContext(), "创建xml文件成功!", Toast.LENGTH_SHORT).show();
085 }
086 //dom解析xml文件
087 private void domParseXML(){
088 File file = new File(BOOKS_PATH);
089 DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
090 DocumentBuilder db = null;
091 try {
092 db = dbf.newDocumentBuilder();
093 } catch (ParserConfigurationException e) {
094 e.printStackTrace();
095 }
096 Document doc = null;
097 try {
098 doc = db.parse(file);
099 } catch (SAXException e) {
100 e.printStackTrace();
101 } catch (IOException e) {
102 e.printStackTrace();
103 }
104 Element root = doc.getDocumentElement();
105 NodeList books = root.getElementsByTagName("book");
106 String res = "本结果是通过dom解析:" + "/n";
107 for(int i = 0; i < books.getLength();i++){
108 Element book = (Element)books.item(i);
109 Element bookname = (Element)book.getElementsByTagName("bookname").item(0);
110 Element bookauthor = (Element)book.getElementsByTagName("bookauthor").item(0);
111 res += "书名: " + bookname.getFirstChild().getNodeValue() + " " +
112 "作者: " + bookauthor.getFirstChild().getNodeValue() + "/n";
113 }
114
115 mTextView.setText(res);
116 }
117
118 //xmlPullParser解析xml文件
119 private void xmlPullParseXML(){
120 String res = "本结果是通过XmlPullParse解析:" + "/n";
121 try {
122 XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
123 XmlPullParser xmlPullParser = factory.newPullParser();
124
125 xmlPullParser.setInput(Thread.currentThread().getContextClassLoader()
126 .getResourceAsStream(BOOKS_PATH), "UTF-8");
127
128 int eventType = xmlPullParser.getEventType();
129
130 try{
131 while (eventType != XmlPullParser.END_DOCUMENT) {
132 String nodeName = xmlPullParser.getName();
133 switch (eventType) {
134 case XmlPullParser.START_TAG:
135 if("bookname".equals(nodeName)){
136 res += "书名: " + xmlPullParser.nextText() + " ";
137 }else if("bookauthor".equals(nodeName)){
138 res += "作者: " + xmlPullParser.nextText() + "/n";
139 }
140 break;
141 default:
142 break;
143 }
144 eventType = xmlPullParser.next();
145 }
146 } catch (IOException e) {
147 e.printStackTrace();
148 }
149 } catch (XmlPullParserException e) {
150 e.printStackTrace();
151 }
152
153 mTextView.setText(res);
154 }
155 //按钮事件响应
156 public void onClick(View v) {
157 if(v == mButton1){
158 createXmlFile();
159 }else if(v == mButton2){
160 domParseXML();
161 }else if(v == mButton3){
162 xmlPullParseXML();
163 }
164 }
165 }

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):

01 <?xml version="1.0" encoding="utf-8"?>
02 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
03 package="com.tutor.xml"
04 android:versionCode="1"
05 android:versionName="1.0">
06 <application android:icon="@drawable/icon" android:label="@string/app_name">
07 <activity android:name=".XmlDemo"
08 android:label="@string/app_name">
09 <intent-filter>
10 <action android:name="android.intent.action.MAIN" />
11 <category android:name="android.intent.category.LAUNCHER" />
12 </intent-filter>
13 </activity>
14 </application>
15 <uses-sdk android:minSdkVersion="7" />
16 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
17 </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:

01 <?xml version='1.0' encoding='UTF-8' standalone='yes' ?>
02 <books>
03 <book>
04 <bookname>Android教程0</bookname>
05 <bookauthor>Frankie0</bookauthor>
06 </book>
07 <book>
08 <bookname>Android教程1</bookname>
09 <bookauthor>Frankie1</bookauthor>
10 </book>
11 <book>
12 <bookname>Android教程2</bookname>
13 <bookauthor>Frankie2</bookauthor>
14 </book>
15 </books>

点击DOM解析XML按钮:

点击XmlPullParse解析XML按钮: