1、 Qt: QXMLStreamReader,读XML文件实例
2、Qt: QXmlStreamWriter Class写XML文件
效果图:
需求:
打开对应格式的XML文件,读入到QTreewidget树中,并能将XML文件另存为,写入到磁盘。
源码:
main.cpp
#include "mainwindow.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}
XbelReader.h
#ifndef XBELREADER_H
#define XBELREADER_H
#include <QIcon>
#include <QXmlStreamReader>
#include <QTreeWidget>
#include <QTreeWidgetItem>
#include <QIcon>
class XbelReader
{
public:
XbelReader(QTreeWidget *tree);
bool read(QIODevice *device);
QString errorString()const;
private:
void readXBEL();
void readTitle(QTreeWidgetItem *item);
void readSeparator(QTreeWidgetItem *item);
void readFolder(QTreeWidgetItem *item);
void readBookmark(QTreeWidgetItem *item);
QTreeWidgetItem *createChildItem(QTreeWidgetItem *item);
private:
QXmlStreamReader xml;
QTreeWidget *treeWidget;
QIcon folderIcon;
QIcon bookmarkIcon;
};
#endif // XBELREADER_H
XbelReader.cpp
#include <QStyle>
#include <QDebug>
#include "xbelreader.h"
XbelReader::XbelReader(QTreeWidget *tree)
{
treeWidget = tree;
QStyle *style = treeWidget->style();
folderIcon.addPixmap(style->standardPixmap(QStyle::SP_DirClosedIcon),
QIcon::Normal,QIcon::Off);
folderIcon.addPixmap(style->standardPixmap(QStyle::SP_DirOpenIcon),
QIcon::Normal,QIcon::On);
bookmarkIcon.addPixmap(style->standardPixmap(QStyle::SP_FileIcon));
}
bool XbelReader::read(QIODevice *device)
{
xml.setDevice(device);
if (xml.readNextStartElement()) //
{
if (xml.name() == "xbel" && xml.attributes().value("version") == "1.0")
readXBEL();
else
xml.raiseError(QObject::tr("The file is not an XBEL version 1.0 file."));
}
return !xml.error(); //非运算,有错返回0,无错返回1
}
QString XbelReader::errorString() const
{
return QObject::tr("%1\nLine %2, column %3")
.arg(xml.errorString())
.arg(xml.lineNumber())
.arg(xml.columnNumber());
}
void XbelReader::readXBEL()
{
Q_ASSERT(xml.isStartElement() && xml.name() == "xbel");
while (xml.readNextStartElement())
{
if (xml.name() == "folder")
readFolder(0);
else if (xml.name() == "bookmark")
readBookmark(0);
else if (xml.name() == "separator")
readSeparator(0);
else
xml.skipCurrentElement();
}
}
void XbelReader::readTitle(QTreeWidgetItem *item)
{
Q_ASSERT(xml.isStartElement() && xml.name() == "title");
QString title = xml.readElementText();
item->setText(0,title);
}
void XbelReader::readSeparator(QTreeWidgetItem *item)
{
Q_ASSERT(xml.isStartElement() && xml.name() == "separator");
QTreeWidgetItem *separator = createChildItem(item);
separator->setFlags(item->flags() & ~Qt::ItemIsSelectable);
separator->setText(0,QString(30,0xB7));
xml.skipCurrentElement();
}
void XbelReader::readFolder(QTreeWidgetItem *item)
{
Q_ASSERT(xml.isStartElement() && xml.name() == "folder");
QTreeWidgetItem *folder = createChildItem(item);
bool folded = (xml.attributes().value("folded") != "no");
treeWidget->setItemExpanded(folder, !folded);
while (xml.readNextStartElement())
{
if (xml.name() == "title")
readTitle(folder);
else if (xml.name() == "folder")
readFolder(folder);
else if (xml.name() == "bookmark")
readBookmark(folder);
else if (xml.name() == "separator")
readSeparator(folder);
else
xml.skipCurrentElement();
}
}
void XbelReader::readBookmark(QTreeWidgetItem *item)
{
Q_ASSERT(xml.isStartElement() && xml.name() == "bookmark");
QTreeWidgetItem *bookmark = createChildItem(item);
bookmark->setFlags(bookmark->flags() | Qt::ItemIsEditable);
bookmark->setIcon(0,bookmarkIcon);
bookmark->setText(0,QObject::tr("Unknown title"));
bookmark->setText(1,xml.attributes().value("href").toString());
while(xml.readNextStartElement())
{
if(xml.name() == "title")
readTitle(bookmark);
else
xml.skipCurrentElement();
}
}
QTreeWidgetItem *XbelReader::createChildItem(QTreeWidgetItem *item)
{
QTreeWidgetItem *childItem;
if (item)
{
childItem = new QTreeWidgetItem(item);
}
else
{
childItem = new QTreeWidgetItem(treeWidget);
}
childItem->setData(0, Qt::UserRole, xml.name().toString());
return childItem;
}
XbelWriter.h
#ifndef XBELWRITER_H
#define XBELWRITER_H
#include <QXmlStreamWriter>
#include <QTreeWidget>
#include <QTreeWidgetItem>
class XbelWriter
{
public:
XbelWriter(QTreeWidget *tree);
bool writeFile(QIODevice *device);
private:
void writeItem(QTreeWidgetItem *item);
QXmlStreamWriter xml;
QTreeWidget *treeWidget;
};
#endif // XBELWRITER_H
XbelWriter.cpp
#include "xbelwriter.h"
XbelWriter::XbelWriter(QTreeWidget *tree)
{
treeWidget = tree;
xml.setAutoFormatting(true); //自动格式化文本
}
bool XbelWriter::writeFile(QIODevice *device)
{
xml.setDevice(device);
xml.writeStartDocument();
xml.writeDTD("<!DOCTYPE xbel>");
xml.writeStartElement("xbel");
xml.writeAttribute("version", "1.0");
for(int i=0 ; i < treeWidget->topLevelItemCount() ; ++i)
writeItem(treeWidget->topLevelItem(i));
xml.writeEndDocument();
return true;
}
void XbelWriter::writeItem(QTreeWidgetItem *item)
{
QString tagName = item->data(0, Qt::UserRole).toString();
if(tagName == "folder")
{
bool folded = !treeWidget->isItemExpanded(item);
xml.writeStartElement(tagName);
xml.writeAttribute("folded",folded ? "yes" : "no");//三目运算
xml.writeTextElement("title", item->text(0));
for(int i=0 ; i<item->childCount() ; ++i)
writeItem(item->child(i));
xml.writeEndElement();
}
else if(tagName == "bookmark")
{
xml.writeStartElement(tagName);
if(!item->text(1).isEmpty())
xml.writeAttribute("href", item->text(1));
xml.writeTextElement("title" , item->text(0));
xml.writeEndElement();
}
else if(tagName == "separator")
{
xml.writeEmptyElement(tagName);
}
}