Qt 5.11 | Qt XML Patterns | Recipes Example | querymainwindow.cpp Example File

Qt 5.11.3 Reference Documentation

# querymainwindow.cpp Example File

recipes/querymainwindow.cpp

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

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

      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);
      }

      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);
      }

      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);
      }

      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()));

      }