mainwindow.cpp Example File

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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_description = description;
          m_sourceLocation = sourceLocation;
      }

  private:
      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();

      const QString fileName = QStringLiteral(":/schema_")
          + QString::number(index) + QStringLiteral(".xsd");
      QFile schemaFile(fileName);
      if (!schemaFile.open(QIODevice::ReadOnly)) {
          qWarning() << "Cannot open" << QDir::toNativeSeparators(fileName)
              << ':' << schemaFile.errorString();
          return;
      }

      const QString schemaText(QString::fromUtf8(schemaFile.readAll()));
      schemaView->setPlainText(schemaText);

      validate();
  }

  void MainWindow::instanceSelected(int index)
  {
      if (index < 0) {
          instanceEdit->setPlainText(QString());
          return;
      }
      const QString fileName = QStringLiteral(":/instance_")
          + QString::number(2 * schemaSelection->currentIndex() + index)
          + QStringLiteral(".xml");
      QFile instanceFile(fileName);
      if (!instanceFile.open(QIODevice::ReadOnly)) {
          qWarning() << "Cannot open" << QDir::toNativeSeparators(fileName)
              << ':' << instanceFile.errorString();
          return;
      }
      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();
  }