Android 中創建與解析XML的方法
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大家好今天我今天給大家講解一下android中xml的創建以及一些解析xml的常用方法。首先是創建，我們用XmlSerializer這個類來創建
一個xml文件，其次是解析xml文件，常用的有dom, sax,
XmlPullParser等方法，由于sax代碼有點復雜，本節只講解一下dom與XmlPullParser解析，sax我將會在下一節單獨講解,至
于幾種解析xml的優缺點我就不再講述了。
為了方便理解，我做了一個簡單的Demo。首先首界面有三個按鈕，點擊第一個按鈕會在sdcard目錄下創建一個books.xml文件,另外兩個按鈕分
別是調用dom與XmlPullParser方法解析xml文件，并將結果顯示在一個TextView里。大家可以按照我的步驟一步步來:
第一步:新建一個Android工程,命名為XmlDemo.
第二步:修改main.xml布局文件，代碼如下:
<?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="創建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,代碼如下:
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);
}
//創建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(), "創建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 = "本結果是通過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 += "書名: " + bookname.getFirstChild().getNodeValue() + " " +
"作者: " + bookauthor.getFirstChild().getNodeValue() + "/n";
}
mTextView.setText(res);
}
//xmlPullParser解析xml文件
private void xmlPullParseXML(){
String res = "本結果是通過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 += "書名: " + 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);
}
//按鈕事件響應
public void onClick(View v) {
if(v == mButton1){
createXmlFile();
}else if(v == mButton2){
domParseXML();
}else if(v == mButton3){
xmlPullParseXML();
}
}
}第四步:由于我們在Sd卡上新建了文件，需要增加權限，如下代碼(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:運行上述工程，查看效果:
啟動首界面:
點擊創建XML文件按鈕,生成books.xml文件
books.xml內容如下:
<?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>點擊DOM解析XML按鈕:
點擊XmlPullParse解析XML按鈕:
fmms
14年前提問