mainwindow.cpp Example File

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 #include <QtGui>

 #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()));
 }