Qt 4.0: mdichild.cpp Example File (mainwindows/mdi/mdichild.cpp)

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# mdichild.cpp Example File
mainwindows/mdi/mdichild.cpp

        /****************************************************************************
        **
        ** Copyright (C) 2005-2005 Trolltech AS. All rights reserved.
        **
        ** This file is part of the documentation of the Qt Toolkit.
        **
        ** This file may be used under the terms of the GNU General Public
    ** License version 2.0 as published by the Free Software Foundation
    ** and appearing in the file LICENSE.GPL included in the packaging of
    ** this file.  Please review the following information to ensure GNU
    ** General Public Licensing requirements will be met:
    ** http://www.trolltech.com/products/qt/opensource.html
    **
    ** If you are unsure which license is appropriate for your use, please
    ** review the following information:
    ** http://www.trolltech.com/products/qt/licensing.html or contact the
    ** sales department at sales@trolltech.com.
        **
        ** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
        ** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        **
        ****************************************************************************/

        #include <QtGui>

        #include "mdichild.h"

        MdiChild::MdiChild()
        {
            setAttribute(Qt::WA_DeleteOnClose);

            connect(document(), SIGNAL(contentsChanged()),
                    this, SLOT(documentWasModified()));
        }

        void MdiChild::newFile()
        {
            static int sequenceNumber = 1;

            isUntitled = true;
            curFile = tr("document%1.txt").arg(sequenceNumber++);
            setWindowTitle(curFile + "[*]");
        }

        bool MdiChild::loadFile(const QString &fileName)
        {
            QFile file(fileName);
            if (!file.open(QFile::ReadOnly | QFile::Text)) {
                QMessageBox::warning(this, tr("MDI"),
                                     tr("Cannot read file %1:\n%2.")
                                     .arg(fileName)
                                     .arg(file.errorString()));
                return false;
            }

            QTextStream in(&file);
            QApplication::setOverrideCursor(Qt::WaitCursor);
            setPlainText(in.readAll());
            QApplication::restoreOverrideCursor();

            setCurrentFile(fileName);
            return true;
        }

        bool MdiChild::save()
        {
            if (isUntitled) {
                return saveAs();
            } else {
                return saveFile(curFile);
            }
        }

        bool MdiChild::saveAs()
        {
            QString fileName = QFileDialog::getSaveFileName(this, tr("Save As"),
                                                            curFile);
            if (fileName.isEmpty())
                return false;

            return saveFile(fileName);
        }

        bool MdiChild::saveFile(const QString &fileName)
        {
            QFile file(fileName);
            if (!file.open(QFile::WriteOnly | QFile::Text)) {
                QMessageBox::warning(this, tr("MDI"),
                                     tr("Cannot write file %1:\n%2.")
                                     .arg(fileName)
                                     .arg(file.errorString()));
                return false;
            }

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

            setCurrentFile(fileName);
            return true;
        }

        QString MdiChild::userFriendlyCurrentFile()
        {
            return strippedName(curFile);
        }

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

        void MdiChild::documentWasModified()
        {
            setWindowModified(document()->isModified());
        }

        bool MdiChild::maybeSave()
        {
            if (document()->isModified()) {
                int ret = QMessageBox::warning(this, tr("MDI"),
                             tr("'%1' has been modified.\n"
                                "Do you want to save your changes?")
                             .arg(userFriendlyCurrentFile()),
                             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 MdiChild::setCurrentFile(const QString &fileName)
        {
            curFile = QFileInfo(fileName).canonicalFilePath();
            document()->setModified(false);
            setWindowModified(false);
            setWindowTitle(userFriendlyCurrentFile() + "[*]");
        }

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