Qt 5.9 | Qt Widgets | Syntax Highlighter Example | mainwindow.cpp Example File

Qt 5.9.9 Reference Documentation

# mainwindow.cpp Example File

richtext/syntaxhighlighter/mainwindow.cpp

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      #include <QtWidgets>

      #include "mainwindow.h"

      MainWindow::MainWindow(QWidget *parent)
          : QMainWindow(parent)
      {
          setupFileMenu();
          setupHelpMenu();
          setupEditor();

          setCentralWidget(editor);
          setWindowTitle(tr("Syntax Highlighter"));
      }

      void MainWindow::about()
      {
          QMessageBox::about(this, tr("About Syntax Highlighter"),
                      tr("<p>The <b>Syntax Highlighter</b> example shows how " \
                         "to perform simple syntax highlighting by subclassing " \
                         "the QSyntaxHighlighter class and describing " \
                         "highlighting rules using regular expressions.</p>"));
      }

      void MainWindow::newFile()
      {
          editor->clear();
      }

      void MainWindow::openFile(const QString &path)
      {
          QString fileName = path;

          if (fileName.isNull())
              fileName = QFileDialog::getOpenFileName(this, tr("Open File"), "", "C++ Files (*.cpp *.h)");

          if (!fileName.isEmpty()) {
              QFile file(fileName);
              if (file.open(QFile::ReadOnly | QFile::Text))
                  editor->setPlainText(file.readAll());
          }
      }

      void MainWindow::setupEditor()
      {
          QFont font;
          font.setFamily("Courier");
          font.setFixedPitch(true);
          font.setPointSize(10);

          editor = new QTextEdit;
          editor->setFont(font);

          highlighter = new Highlighter(editor->document());

          QFile file("mainwindow.h");
          if (file.open(QFile::ReadOnly | QFile::Text))
              editor->setPlainText(file.readAll());
      }

      void MainWindow::setupFileMenu()
      {
          QMenu *fileMenu = new QMenu(tr("&File"), this);
          menuBar()->addMenu(fileMenu);

          fileMenu->addAction(tr("&New"), this, SLOT(newFile()), QKeySequence::New);
          fileMenu->addAction(tr("&Open..."), this, SLOT(openFile()), QKeySequence::Open);
          fileMenu->addAction(tr("E&xit"), qApp, SLOT(quit()), QKeySequence::Quit);
      }

      void MainWindow::setupHelpMenu()
      {
          QMenu *helpMenu = new QMenu(tr("&Help"), this);
          menuBar()->addMenu(helpMenu);

          helpMenu->addAction(tr("&About"), this, SLOT(about()));
          helpMenu->addAction(tr("About &Qt"), qApp, SLOT(aboutQt()));
      }