依賴的標頭檔案：

#include <QFile> 
#include <QString>
#include <QtXml>
#include <QDomDocument>
#include <QDateTime>

//寫xml操作。sXmlFilePath：要寫入的xml檔案路徑
int CAppletGenerator::addTaskMenuTreeItem(QString sXmlFilePath)
{
	QFile file(sXmlFilePath);
	if (!file.open(QFile::ReadOnly | QFile::Text)) {
		return -1;
	}

	QDomDocument domDocument;
	if (!domDocument.setContent(&file, true)) {
		file.close();
		return -1;
	}
	QDomElement tree      = domDocument.documentElement();
	QDomElement firstItem = tree.firstChildElement();

	//在firstitem上新增一個節點
	QDomElement secondItem = domDocument.createElement("item");

	//獲取當前時間，用於節點的唯一性id
	QDateTime dt;
	QTime time;
	QDate date;
	dt.setTime(time.currentTime());
	dt.setDate(date.currentDate());
	QString currentDate = dt.toString("yyyyMMddhhmmss");

	//為節點新增屬性
	secondItem.setAttribute("id",currentDate);
	secondItem.setAttribute("select","1");
	secondItem.setAttribute("text","節點");

	//新增元素節點到父節點
	firstItem.appendChild(secondItem);
	file.close();

	QFile fileModify(sXmlFilePath);
	if (!fileModify.open(QFile::WriteOnly | QFile::Text)){
		return -1;
	}

	//核心程式碼：Dom方式寫xml檔案
	QTextStream out(&fileModify);
	domDocument.save(out,4);
	fileModify.close();
	return 0;

}