- Qt 5.5
- Qt Widgets
- Syntax Highlighter Example
- mainwindow.cpp Example File
- Qt 5.5.1 Reference Documentation

# mainwindow.cpp Example File

richtext/syntaxhighlighter/mainwindow.cpp

    /****************************************************************************
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    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
    **
    ** 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:
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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()));
    }