那个例子是在按照网上博客《Qt数据库（XML）》改写的一个操做XML的实现。
借鉴了良多里面的代码，各人能够连系上面的博客对照，相信你必定会对XML的操做纯熟起来。
我成立的是Qwidget项目，没有添加ui文件，输出内容都放在应用法式输出中（qDebug）。
XMLtest.PRo文件代码：
#-------------------------------------------------## Project created by QtCreator 2012-08-15T15:56:54##-------------------------------------------------QT += core gui xmlTARGET = XMLtestTEMPLATE = appSOURCES += main.cpp\widget.cppHEADERS += widget.hwidget.h文件代码：
#ifndef WIDGET_H#define WIDGET_H#include <QtGui/QWidget>#include <QtCore>class Widget : public QWidget{Q_OBJECTpublic:Widget(QWidget *parent = 0);~Widget();void read_xml(QString filename);void create_xml(QString filename);void add_xmlnode(QString filename,QString rmt_name,QString ipa,QString ipb);void do_xml(const QString opt,QString filename);private:};#endif // WIDGET_Hwidget.cpp文件代码：
#include "widget.h"#include "qfile.h"#include "qdebug.h"#include <QDomDocument>#include "qtextcodec.h"Widget::Widget(QWidget *parent): QWidget(parent){QTextCodec::setCodecForCStrings(QTextCodec::codecForName("GB2312"));QFile *file;QString filename = "config.xml";if(file->exists("config.xml")){read_xml(filename);}else{create_xml(filename);}add_xmlnode(filename,"remote1","127.0.0.1","192.168.1.199");do_xml("update",filename);}Widget::~Widget(){}void Widget::do_xml(const QString opt,QString filename){QFile file(filename);if(!file.oPEn(QIODevice::ReadOnly | QIODevice::Text)){qDebug() << "open for do erro";file.close();}QDomDocument doc;if(!doc.setContent(&file)){qDebug() << "setcontent for do error";file.close();}file.close();QDomNodeList lists = doc.elementsByTagName("remote");QDomElement ele = lists.at(1).toElement();if(ele.attribute(tr("id")) == "3"){if("delete" == opt || "update" == opt){QDomElement root = doc.documentElement();if("delete" == opt){root.removeChild(lists.at(1));qDebug() << "remove ok !";}else{QDomNodeList child=lists.at(1).childNodes();child.at(0).toElement().firstChild().setNodeValue("namechanged");child.at(1).toElement().firstChild().setNodeValue("ipachanged");child.at(2).toElement().firstChild().setNodeValue("ipbchanged");qDebug() << "modify ok !";}if(!file.open(QIODevice::WriteOnly | QIODevice::Text)){qDebug() << "open for remove error!";}QTextStream out(&file);doc.save(out,4);file.close();}}}void Widget::add_xmlnode(QString filename,QString rmt_name, QString ipa, QString ipb){QFile file(filename);if (!file.open(QIODevice::ReadOnly | QFile::Text)) {qDebug()<<"open for add error..." ;}QDomDocument doc;QString errorStr;int errorLine;int errorColumn;if (!doc.setContent(&file, false, &errorStr, &errorLine, &errorColumn)) {qDebug()<<"add setcontent error..." ;file.close();}//QDomNode node = doc.firstChild();file.close();QDomElement root = doc.documentElement();if(root.isNull()){root = doc.createElement("ipconfig");}QDomElement element_root = doc.createElement(tr("remote"));QDomAttr attr_id = doc.createAttribute(tr("id"));QDomElement element_rmt = doc.createElement(tr("rmt_name"));QDomElement element_ipa = doc.createElement(tr("ipa"));QDomElement element_ipb = doc.createElement(tr("ipb"));QString str_id;if(root.lastChild().isNull()){str_id = "1";attr_id.setValue(str_id);}else{str_id = root.lastChild().toElement().attribute(tr("id"));int count = str_id.toInt()+1;attr_id.setValue(QString::number(count));}QDomText text;text =doc.createTextNode(rmt_name);element_rmt.appenDChild(text);text = doc.createTextNode(ipa);element_ipa.appendChild(text);text = doc.createTextNode(ipb);element_ipb.appendChild(text);text.clear();element_root.appendChild(element_rmt);element_root.appendChild(element_ipa);element_root.appendChild(element_ipb);element_root.setAttributeNode(attr_id);root.appendChild(element_root);if(!file.open(QIODevice::WriteOnly|QIODevice::Append))qDebug() << "open for add error!";QTextStream out(&file);doc.save(out,4);file.close();}void Widget::read_xml(QString filename){QFile file(filename);if (!file.open(QIODevice::ReadOnly | QFile::Text)) {qDebug()<<"open for read error..." ;}QString errorStr;int errorLine;int errorColumn;QDomDocument doc;if (!doc.setContent(&file, false, &errorStr, &errorLine, &errorColumn)) {qDebug()<<"setcontent error..." ;file.close();}file.close();QDomElement root = doc.documentElement();if (root.tagName() != "ipconfig") {qDebug()<<"root.tagname != ipconfig..." ;}QDomNode node = root.firstChild();while(!node.isNull()){if(node.isElement()){QDomElement element = node.toElement();qDebug() << qPrintable(element.tagName())<<qPrintable(element.attribute("id"));QDomNodeList list = element.childNodes();for(int i = 0;i < list.count();i++){QDomNode nodechild = list.at(i);if(nodechild.isElement()){qDebug() << " " << qPrintable(nodechild.toElement().tagName()) << qPrintable(nodechild.toElement().text());}}}node = node.nextSibling();}}void Widget::create_xml(QString filename){QFile file(filename);file.open(QIODevice::ReadWrite);QDomDocument doc;QDomProcessingInstruction instruction;instruction = doc.createProcessingInstruction("xml","version=\"1.0\" encoding=\"GB2312\"");doc.appendChild(instruction);QDomElement root = doc.createElement("ipconfig");doc.appendChild(root);QDomText text = doc.createTextNode("");root.appendChild(text);QTextStream out(&file);doc.save(out,4);file.close();}main.cpp文件代码：#include <QtGui/QApplication>#include "widget.h"int main(int argc, char *argv[]){QApplication a(argc, argv);Widget w;w.show();return a.exec();}XML文件构造：<?xml version='1.0' encoding='GB2312'?><ipconfig><remote id="1"><rmt_name>remote1</rmt_name><ipa>127.0.0.1</ipa><ipb>192.168.1.199</ipb></remote><remote id="3"><rmt_name>namechanged</rmt_name><ipa>ipachanged</ipa><ipb>ipbchanged</ipb></remote><remote id="4"><rmt_name>remote1</rmt_name><ipa>127.0.0.1</ipa><ipb>192.168.1.199</ipb></remote><remote id="5"><rmt_name>remote1</rmt_name><ipa>127.0.0.1</ipa><ipb>192.168.1.199</ipb></remote><remote id="6"><rmt_name>remote1</rmt_name><ipa>127.0.0.1</ipa><ipb>192.168.1.199</ipb></remote><remote id="7"><rmt_name>remote1</rmt_name><ipa>127.0.0.1</ipa><ipb>192.168.1.199</ipb></remote><remote id="8"><rmt_name>remote1</rmt_name><ipa>127.0.0.1</ipa><ipb>192.168.1.199</ipb></remote></ipconfig>应用法式输出：
remote 1
rmt_name remote1
ipa 127.0.0.1
ipb 192.168.1.199
remote 3
rmt_name remote1
ipa 127.0.0.1
ipb 192.168.1.199
remote 4
rmt_name remote1
ipa 127.0.0.1
ipb 192.168.1.199
remote 5
rmt_name remote1
ipa 127.0.0.1
ipb 192.168.1.199
remote 6
rmt_name remote1
ipa 127.0.0.1
ipb 192.168.1.199
remote 7
rmt_name remote1
ipa 127.0.0.1
ipb 192.168.1.199
modify ok !
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