Qt Reference Documentation

# querymainwindow.cpp Example File

xmlpatterns/recipes/querymainwindow.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
     ** All rights reserved.
     ** Contact: Nokia Corporation (qt-info@nokia.com)
     **
     ** This file is part of the examples of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:BSD$
     ** You may use this file under the terms of the BSD license as follows:
     **
     ** "Redistribution and use in source and binary forms, with or without
     ** modification, are permitted provided that the following conditions are
     ** met:
     **   * Redistributions of source code must retain the above copyright
     **     notice, this list of conditions and the following disclaimer.
     **   * Redistributions in binary form must reproduce the above copyright
     **     notice, this list of conditions and the following disclaimer in
     **     the documentation and/or other materials provided with the
     **     distribution.
     **   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
     **     the names of its contributors may be used to endorse or promote
     **     products derived from this software without specific prior written
     **     permission.
     **
     ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
     ** $QT_END_LICENSE$
     **
     ****************************************************************************/

     #include <QtGui>
     #include <QtXmlPatterns>

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

     QueryMainWindow::QueryMainWindow() : ui_defaultQueries(0)
     {
         setupUi(this);

         new XmlSyntaxHighlighter(qFindChild<QTextEdit*>(this, "inputTextEdit")->document());
         new XmlSyntaxHighlighter(qFindChild<QTextEdit*>(this, "outputTextEdit")->document());

         ui_defaultQueries = qFindChild<QComboBox*>(this, "defaultQueries");
         QMetaObject::connectSlotsByName(this);
         connect(ui_defaultQueries, SIGNAL(currentIndexChanged(int)), SLOT(displayQuery(int)));

         loadInputFile();
         const QStringList queries(QDir(":/files/", "*.xq").entryList());
         int len = queries.count();
         for(int i = 0; i < len; ++i)
             ui_defaultQueries->addItem(queries.at(i));
     }

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

         evaluate(query);
     }

     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();
         qFindChild<QTextEdit*>(this, "inputTextEdit")->setPlainText(inputDocument);
     }

     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();
         qFindChild<QTextEdit*>(this, "outputTextEdit")->setPlainText(QString::fromUtf8(outArray.constData()));

     }