qt-everywhere-src-5.14.1/qtxmlpatterns/examples/xmlpatterns/recipes/querymainwindow.cpp

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#include <QtWidgets/QMessageBox>
#include <QtWidgets/QFileDialog>
#include <QtXmlPatterns>

#include "querymainwindow.h"
#include "xmlsyntaxhighlighter.h"

//! [0]
QueryMainWindow::QueryMainWindow()
{
    setupUi(this);

    new XmlSyntaxHighlighter(findChild<QTextEdit*>("inputTextEdit")->document());
    new XmlSyntaxHighlighter(findChild<QTextEdit*>("outputTextEdit")->document());

    ui_defaultQueries = findChild<QComboBox*>("defaultQueries");
    QMetaObject::connectSlotsByName(this);

    connect(ui_defaultQueries, QOverload<int>::of(&QComboBox::currentIndexChanged),
            this, &QueryMainWindow::displayQuery);

    loadInputFile();
    const QStringList queries(QDir(":/files/", "*.xq").entryList());
    for (const auto &query : queries)
        ui_defaultQueries->addItem(query);
    if (queries.count() > 0)
        displayQuery(0);
}
//! [0]


//! [1]
void QueryMainWindow::displayQuery(int index)
{
    QFile queryFile(QString(":files/") + ui_defaultQueries->itemText(index));
    queryFile.open(QIODevice::ReadOnly);
    const QString query(QString::fromLatin1(queryFile.readAll()));
    findChild<QTextEdit*>("queryTextEdit")->setPlainText(query);

    evaluate(query);
}
//! [1]


void QueryMainWindow::loadInputFile()
{
    QFile forView;
    forView.setFileName(":/files/cookbook.xml");
    if (!forView.open(QIODevice::ReadOnly)) {
        QMessageBox::information(this,
            tr("Unable to open file"), forView.errorString());
        return;
    }

    QTextStream in(&forView);
    QString inputDocument = in.readAll();
    findChild<QTextEdit*>("inputTextEdit")->setPlainText(inputDocument);
}


//! [2]
void QueryMainWindow::evaluate(const QString &str)
{
    QFile sourceDocument;
    sourceDocument.setFileName(":/files/cookbook.xml");
    sourceDocument.open(QIODevice::ReadOnly);

    QByteArray outArray;
    QBuffer buffer(&outArray);
    buffer.open(QIODevice::ReadWrite);

    QXmlQuery query;
    query.bindVariable("inputDocument", &sourceDocument);
    query.setQuery(str);
    if (!query.isValid())
        return;

    QXmlFormatter formatter(query, &buffer);
    if (!query.evaluateTo(&formatter))
        return;

    buffer.close();
    findChild<QTextEdit*>("outputTextEdit")->setPlainText(QString::fromUtf8(outArray.constData()));

}
//! [2]