Qt Reference Documentation

# mainwindow.cpp Example File

xmlpatterns/schema/mainwindow.cpp

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     ** This file is part of the examples of the Qt Toolkit.
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     #include <QtGui>
     #include <QtXmlPatterns>

     #include "mainwindow.h"
     #include "xmlsyntaxhighlighter.h"

     class MessageHandler : public QAbstractMessageHandler
     {
         public:
             MessageHandler()
                 : QAbstractMessageHandler(0)
             {
             }

             QString statusMessage() const
             {
                 return m_description;
             }

             int line() const
             {
                 return m_sourceLocation.line();
             }

             int column() const
             {
                 return m_sourceLocation.column();
             }

         protected:
             virtual void handleMessage(QtMsgType type, const QString &description,
                                        const QUrl &identifier, const QSourceLocation &sourceLocation)
             {
                 Q_UNUSED(type);
                 Q_UNUSED(identifier);

                 m_messageType = type;
                 m_description = description;
                 m_sourceLocation = sourceLocation;
             }

         private:
             QtMsgType m_messageType;
             QString m_description;
             QSourceLocation m_sourceLocation;
     };

     MainWindow::MainWindow()
     {
         setupUi(this);

         new XmlSyntaxHighlighter(schemaView->document());
         new XmlSyntaxHighlighter(instanceEdit->document());

         schemaSelection->addItem(tr("Contact Schema"));
         schemaSelection->addItem(tr("Recipe Schema"));
         schemaSelection->addItem(tr("Order Schema"));

         instanceSelection->addItem(tr("Valid Contact Instance"));
         instanceSelection->addItem(tr("Invalid Contact Instance"));

         connect(schemaSelection, SIGNAL(currentIndexChanged(int)), SLOT(schemaSelected(int)));
         connect(instanceSelection, SIGNAL(currentIndexChanged(int)), SLOT(instanceSelected(int)));
         connect(validateButton, SIGNAL(clicked()), SLOT(validate()));
         connect(instanceEdit, SIGNAL(textChanged()), SLOT(textChanged()));

         validationStatus->setAlignment(Qt::AlignCenter | Qt::AlignVCenter);

         schemaSelected(0);
         instanceSelected(0);
     }

     void MainWindow::schemaSelected(int index)
     {
         instanceSelection->clear();
         if (index == 0) {
             instanceSelection->addItem(tr("Valid Contact Instance"));
             instanceSelection->addItem(tr("Invalid Contact Instance"));
         } else if (index == 1) {
             instanceSelection->addItem(tr("Valid Recipe Instance"));
             instanceSelection->addItem(tr("Invalid Recipe Instance"));
         } else if (index == 2) {
             instanceSelection->addItem(tr("Valid Order Instance"));
             instanceSelection->addItem(tr("Invalid Order Instance"));
         }
         textChanged();

         QFile schemaFile(QString(":/schema_%1.xsd").arg(index));
         schemaFile.open(QIODevice::ReadOnly);
         const QString schemaText(QString::fromUtf8(schemaFile.readAll()));
         schemaView->setPlainText(schemaText);

         validate();
     }

     void MainWindow::instanceSelected(int index)
     {
         QFile instanceFile(QString(":/instance_%1.xml").arg((2*schemaSelection->currentIndex()) + index));
         instanceFile.open(QIODevice::ReadOnly);
         const QString instanceText(QString::fromUtf8(instanceFile.readAll()));
         instanceEdit->setPlainText(instanceText);

         validate();
     }

     void MainWindow::validate()
     {
         const QByteArray schemaData = schemaView->toPlainText().toUtf8();
         const QByteArray instanceData = instanceEdit->toPlainText().toUtf8();

         MessageHandler messageHandler;

         QXmlSchema schema;
         schema.setMessageHandler(&messageHandler);

         schema.load(schemaData);

         bool errorOccurred = false;
         if (!schema.isValid()) {
             errorOccurred = true;
         } else {
             QXmlSchemaValidator validator(schema);
             if (!validator.validate(instanceData))
                 errorOccurred = true;
         }

         if (errorOccurred) {
             validationStatus->setText(messageHandler.statusMessage());
             moveCursor(messageHandler.line(), messageHandler.column());
         } else {
             validationStatus->setText(tr("validation successful"));
         }

         const QString styleSheet = QString("QLabel {background: %1; padding: 3px}")
                                           .arg(errorOccurred ? QColor(Qt::red).lighter(160).name() :
                                                                QColor(Qt::green).lighter(160).name());
         validationStatus->setStyleSheet(styleSheet);
     }

     void MainWindow::textChanged()
     {
         instanceEdit->setExtraSelections(QList<QTextEdit::ExtraSelection>());
     }

     void MainWindow::moveCursor(int line, int column)
     {
         instanceEdit->moveCursor(QTextCursor::Start);
         for (int i = 1; i < line; ++i)
             instanceEdit->moveCursor(QTextCursor::Down);

         for (int i = 1; i < column; ++i)
             instanceEdit->moveCursor(QTextCursor::Right);

         QList<QTextEdit::ExtraSelection> extraSelections;
         QTextEdit::ExtraSelection selection;

         const QColor lineColor = QColor(Qt::red).lighter(160);
         selection.format.setBackground(lineColor);
         selection.format.setProperty(QTextFormat::FullWidthSelection, true);
         selection.cursor = instanceEdit->textCursor();
         selection.cursor.clearSelection();
         extraSelections.append(selection);

         instanceEdit->setExtraSelections(extraSelections);

         instanceEdit->setFocus();
     }