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mainwindow.cpp Example File
mainwindows/application/mainwindow.cpp

    #include <QtGui>

    #include "mainwindow.h"

    MainWindow::MainWindow()
    {
        textEdit = new QTextEdit(this);
        setCentralWidget(textEdit);

        createActions();
        createMenus();
        createToolBars();
        createStatusBar();

        readSettings();

        connect(textEdit->document(), SIGNAL(contentsChanged()),
                this, SLOT(documentWasModified()));

        setWindowTitle(tr("Application"));

        printer = 0;
    }

    void MainWindow::closeEvent(QCloseEvent *event)
    {
        if (maybeSave()) {
            writeSettings();
            event->accept();
        } else {
            event->ignore();
        }
    }

    void MainWindow::newFile()
    {
        if (maybeSave()) {
            textEdit->clear();
            setCurrentFile("");
        }
    }

    void MainWindow::open()
    {
        if (maybeSave()) {
            QString fileName = QFileDialog::getOpenFileName(this);
            if (!fileName.isEmpty())
                loadFile(fileName);
        }
    }

    bool MainWindow::save()
    {
        if (curFile.isEmpty()) {
            return saveAs();
        } else {
            saveFile(curFile);
            return true;
        }
    }

    bool MainWindow::saveAs()
    {
        QString fileName = QFileDialog::getSaveFileName(this);
        if (fileName.isEmpty())
            return false;

        if (QFile::exists(fileName)) {
            int ret = QMessageBox::warning(this, tr("Application"),
                         tr("File %1 already exists.\n"
                            "Do you want to overwrite it?")
                         .arg(QDir::convertSeparators(fileName)),
                         QMessageBox::Yes | QMessageBox::Default,
                         QMessageBox::No | QMessageBox::Escape);
            if (ret == QMessageBox::No)
                return true;
        }
        if (!fileName.isEmpty())
            saveFile(fileName);
        return true;
    }

    void MainWindow::about()
    {
       QMessageBox::about(this, tr("About Application"),
                tr("The <b>Application</b> example demonstrates how to "
                   "write modern GUI applications using Qt, with a menu bar, "
                   "toolbars, and a status bar."));
    }

    void MainWindow::documentWasModified()
    {
        modLabel->setText(tr("MOD"));
    }

    void MainWindow::createActions()
    {
        newAct = new QAction(QPixmap(":/images/new.png"), tr("&New"), this);
        newAct->setShortcut(tr("Ctrl+N"));
        newAct->setStatusTip(tr("Create a new file"));
        connect(newAct, SIGNAL(triggered()), this, SLOT(newFile()));

        openAct = new QAction(QPixmap(":/images/open.png"), tr("&Open..."), this);
        openAct->setShortcut(tr("Ctrl+O"));
        openAct->setStatusTip(tr("Open an existing file"));
        connect(openAct, SIGNAL(triggered()), this, SLOT(open()));

        saveAct = new QAction(QPixmap(":/images/save.png"), tr("&Save"), this);
        saveAct->setShortcut(tr("Ctrl+S"));
        saveAct->setStatusTip(tr("Save the document to disk"));
        connect(saveAct, SIGNAL(triggered()), this, SLOT(save()));

        saveAsAct = new QAction(tr("Save &As..."), this);
        saveAsAct->setStatusTip(tr("Save the document under a new name"));
        connect(saveAsAct, SIGNAL(triggered()), this, SLOT(saveAs()));

        exitAct = new QAction(tr("E&xit"), this);
        exitAct->setShortcut(tr("Ctrl+Q"));
        exitAct->setStatusTip(tr("Exit the application"));
        connect(exitAct, SIGNAL(triggered()), this, SLOT(close()));

        cutAct = new QAction(QPixmap(":/images/cut.png"), tr("Cu&t"), this);
        cutAct->setShortcut(tr("Ctrl+X"));
        cutAct->setStatusTip(tr("Cut the current selection's contents to the "
                                "clipboard"));
        connect(cutAct, SIGNAL(triggered()), textEdit, SLOT(cut()));

        copyAct = new QAction(QPixmap(":/images/copy.png"), tr("&Copy"), this);
        copyAct->setShortcut(tr("Ctrl+C"));
        copyAct->setStatusTip(tr("Copy the current selection's contents to the "
                                 "clipboard"));
        connect(copyAct, SIGNAL(triggered()), textEdit, SLOT(copy()));

        pasteAct = new QAction(QPixmap(":/images/paste.png"), tr("&Paste"), this);
        pasteAct->setShortcut(tr("Ctrl+V"));
        pasteAct->setStatusTip(tr("Paste the clipboard's contents into the current "
                                  "selection"));
        connect(pasteAct, SIGNAL(triggered()), textEdit, SLOT(paste()));

        aboutAct = new QAction(tr("&About"), this);
        aboutAct->setStatusTip(tr("Show the application's About box"));
        connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));

        aboutQtAct = new QAction(tr("About &Qt"), this);
        aboutQtAct->setStatusTip(tr("Show the Qt library's About box"));
        connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));

        printSetupAct = new QAction(tr("Print"), this);
        connect(printSetupAct, SIGNAL(triggered()), this, SLOT(printSetup()));

        pageSetupAct = new QAction(tr("Page Setup"), this);
        connect(pageSetupAct, SIGNAL(triggered()), this, SLOT(pageSetup()));
    }

    void MainWindow::createMenus()
    {
        fileMenu = menuBar()->addMenu(tr("&File"));
        fileMenu->addAction(newAct);
        fileMenu->addAction(openAct);
        fileMenu->addAction(saveAct);
        fileMenu->addAction(saveAsAct);
        fileMenu->addSeparator();
        fileMenu->addAction(printSetupAct);
        fileMenu->addAction(pageSetupAct);
        fileMenu->addSeparator();
        fileMenu->addAction(exitAct);

        editMenu = menuBar()->addMenu(tr("&Edit"));
        editMenu->addAction(cutAct);
        editMenu->addAction(copyAct);
        editMenu->addAction(pasteAct);

        menuBar()->addSeparator();

        helpMenu = menuBar()->addMenu(tr("&Help"));
        helpMenu->addAction(aboutAct);
        helpMenu->addAction(aboutQtAct);
    }

    void MainWindow::createToolBars()
    {
        fileToolBar = new QToolBar(this);
        fileToolBar->setWindowTitle(tr("File"));
        fileToolBar->addAction(newAct);
        fileToolBar->addAction(openAct);
        fileToolBar->addAction(saveAct);
        addToolBar(fileToolBar);

        editToolBar = new QToolBar(this);
        editToolBar->setWindowTitle(tr("Edit"));
        editToolBar->addAction(cutAct);
        editToolBar->addAction(copyAct);
        editToolBar->addAction(pasteAct);
        addToolBar(editToolBar);
    }

    void MainWindow::createStatusBar()
    {
        modLabel = new QLabel(tr(" MOD "));
        modLabel->setAlignment(Qt::AlignHCenter);
        modLabel->setMinimumSize(modLabel->sizeHint());
        modLabel->clear();

        statusBar()->addWidget(modLabel, 0, true);
    }

    void MainWindow::readSettings()
    {
        QSettings settings("doc.trolltech.com", "Application");
        QPoint pos = settings.value("pos", QPoint(200, 200)).toPoint();
        QSize size = settings.value("size", QSize(400, 400)).toSize();
        resize(size);
        move(pos);
    }

    void MainWindow::writeSettings()
    {
        QSettings settings("doc.trolltech.com", "Application");
        settings.setValue("pos", pos());
        settings.setValue("size", size());
    }

    bool MainWindow::maybeSave()
    {
        if (textEdit->document()->isModified()) {
            int ret = QMessageBox::warning(this, tr("Application"),
                         tr("The document has been modified.\n"
                            "Do you want to save your changes?"),
                         QMessageBox::Yes | QMessageBox::Default,
                         QMessageBox::No,
                         QMessageBox::Cancel | QMessageBox::Escape);
            if (ret == QMessageBox::Yes)
                return save();
            else if (ret == QMessageBox::Cancel)
                return false;
        }
        return true;
    }

    void MainWindow::loadFile(const QString &fileName)
    {
        QFile file(fileName);
        if (!file.open(QFile::ReadOnly)) {
            QMessageBox::warning(this, tr("Application"),
                                 tr("Cannot read file %1:\n%2.")
                                 .arg(fileName)
                                 .arg(file.errorString()));
            return;
        }

        QTextStream in(&file);
        QApplication::setOverrideCursor(Qt::WaitCursor);
        textEdit->setPlainText(in.read());
        QApplication::restoreOverrideCursor();

        setCurrentFile(fileName);
        statusBar()->message(tr("File loaded"), 2000);
    }

    void MainWindow::saveFile(const QString &fileName)
    {
        QFile file(fileName);
        if (!file.open(QFile::WriteOnly)) {
            QMessageBox::warning(this, tr("Application"),
                                 tr("Cannot write file %1:\n%2.")
                                 .arg(fileName)
                                 .arg(file.errorString()));
            return;
        }

        QTextStream out(&file);
        QApplication::setOverrideCursor(Qt::WaitCursor);
        out << textEdit->toPlainText();
        QApplication::restoreOverrideCursor();

        setCurrentFile(fileName);
        statusBar()->message(tr("File saved"), 2000);
    }

    void MainWindow::setCurrentFile(const QString &fileName)
    {
        curFile = fileName;
        modLabel->clear();
        textEdit->document()->setModified(false);

        if (curFile.isEmpty())
            setWindowTitle(tr("Application"));
        else
            setWindowTitle(tr("%1 - %2").arg(strippedName(curFile))
                                        .arg(tr("Application")));
    }

    QString MainWindow::strippedName(const QString &fullFileName)
    {
        return QFileInfo(fullFileName).fileName();
    }

    void MainWindow::printSetup()
    {
        if (!printer)
            printer = new QPrinter;
        QPrintDialog dialog(printer);
        dialog.exec();
    }

    void MainWindow::pageSetup()
    {
        if (!printer)
            printer = new QPrinter;
        QPrintDialog dialog(printer);
        dialog.exec();
    }


Copyright © 2004 Trolltech Trademarks
Qt 4.0.0-b1