Qt Write and Read XML File 读写XML文件

来源：互联网发布：知乎登录过于频繁编辑：程序博客网时间：2024/06/06 13:12

在Qt中，我们有时候需要把一些参数写入xml文件，方便以后可以读入，类似一种存档读档的操作，例如，我们想生成如下的xml文件：

<?xml version="1.0" encoding="UTF-8"?><Parameters>    <para1>1</para1>    <para2>2</para2>    <para3>3</para3></Parameters>

那么写入的操作请参见如下代码：

void QtMainWindow::on_actionSave_triggered() {    QString filename = QFileDialog::getSaveFileName(this,        tr("Save Xml"), ".",        tr("Xml files (*.xml)"));    QFile file(filename);    file.open(QIODevice::WriteOnly);    QXmlStreamWriter xmlWriter(&file);    xmlWriter.setAutoFormatting(true);    xmlWriter.writeStartDocument();    xmlWriter.writeStartElement("Parameters");    xmlWriter.writeTextElement("para1",QString::number(1));    xmlWriter.writeTextElement("para2",QString::number(2));    xmlWriter.writeTextElement("para3",QString::number(3));    xmlWriter.writeEndElement();    xmlWriter.writeEndDocument();    file.close();}

读入的操作请参见如下：

void QtMainWindow::on_actionLoad_triggered() {    QString filename = QFileDialog::getOpenFileName(this,        tr("Open Xml"), ".",        tr("Xml files (*.xml)"));    QFile file(filename);    if (!file.open(QFile::ReadOnly | QFile::Text)) {        std::cerr << "Error: Cannot read file " << qPrintable(filename)            << ": " << qPrintable(file.errorString())            << std::endl;    }    QXmlStreamReader xmlReader(&file);    xmlReader.readNext();    while(!xmlReader.atEnd()) {        if(xmlReader.isStartElement()) {            if(xmlReader.name() == "Parameters") {                xmlReader.readNext();            } else if (xmlReader.name() == "para1") {                int para1 = xmlReader.readElementText().toInt();                xmlReader.readNext();            } else if (xmlReader.name() == "preFilterCap") {                int para2 = xmlReader.readElementText().toInt();                xmlReader.readNext();            } else if (xmlReader.name() == "SADWindowSize") {                int para3 = xmlReader.readElementText().toInt();                xmlReader.readNext();            } else {                xmlReader.raiseError(QObject::tr("Not a options file"));            }        } else {            xmlReader.readNext();        }        file.close();        if (xmlReader.hasError()) {            std::cerr << "Error: Failed to parse file "                << qPrintable(filename) << ": "                << qPrintable(xmlReader.errorString()) << std::endl;        } else if (file.error() != QFile::NoError) {            std::cerr << "Error: Cannot read file " << qPrintable(filename)                << ": " << qPrintable(file.errorString())                << std::endl;        }    }}

阅读全文

0 0