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

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# mainwindow.cpp Example File
mainwindows/mdi/mainwindow.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 "mainwindow.h"
        #include "mdichild.h"

        MainWindow::MainWindow()
        {
            workspace = new QWorkspace;
            setCentralWidget(workspace);
            connect(workspace, SIGNAL(windowActivated(QWidget *)),
                    this, SLOT(updateMenus()));
            windowMapper = new QSignalMapper(this);
            connect(windowMapper, SIGNAL(mapped(QWidget *)),
                    workspace, SLOT(setActiveWindow(QWidget *)));

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

            readSettings();

            setWindowTitle(tr("MDI"));
        }

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

        void MainWindow::newFile()
        {
            MdiChild *child = createMdiChild();
            child->newFile();
            child->show();
        }

        void MainWindow::open()
        {
            QString fileName = QFileDialog::getOpenFileName(this);
            if (!fileName.isEmpty()) {
                MdiChild *existing = findMdiChild(fileName);
                if (existing) {
                    workspace->setActiveWindow(existing);
                    return;
                }

                MdiChild *child = createMdiChild();
                if (child->loadFile(fileName)) {
                    statusBar()->showMessage(tr("File loaded"), 2000);
                    child->show();
                } else {
                    child->close();
                }
            }
        }

        void MainWindow::save()
        {
            if (activeMdiChild()->save())
                statusBar()->showMessage(tr("File saved"), 2000);
        }

        void MainWindow::saveAs()
        {
            if (activeMdiChild()->saveAs())
                statusBar()->showMessage(tr("File saved"), 2000);
        }

        void MainWindow::cut()
        {
            activeMdiChild()->cut();
        }

        void MainWindow::copy()
        {
            activeMdiChild()->copy();
        }

        void MainWindow::paste()
        {
            activeMdiChild()->paste();
        }

        void MainWindow::about()
        {
           QMessageBox::about(this, tr("About MDI"),
                    tr("The <b>MDI</b> example demonstrates how to write multiple "
                       "document interface applications using Qt."));
        }

        void MainWindow::updateMenus()
        {
            bool hasMdiChild = (activeMdiChild() != 0);
            saveAct->setEnabled(hasMdiChild);
            saveAsAct->setEnabled(hasMdiChild);
            pasteAct->setEnabled(hasMdiChild);
            closeAct->setEnabled(hasMdiChild);
            closeAllAct->setEnabled(hasMdiChild);
            tileAct->setEnabled(hasMdiChild);
            cascadeAct->setEnabled(hasMdiChild);
            nextAct->setEnabled(hasMdiChild);
            previousAct->setEnabled(hasMdiChild);
            separatorAct->setVisible(hasMdiChild);

            bool hasSelection = (activeMdiChild() &&
                                 activeMdiChild()->textCursor().hasSelection());
            cutAct->setEnabled(hasSelection);
            copyAct->setEnabled(hasSelection);
        }

        void MainWindow::updateWindowMenu()
        {
            windowMenu->clear();
            windowMenu->addAction(closeAct);
            windowMenu->addAction(closeAllAct);
            windowMenu->addSeparator();
            windowMenu->addAction(tileAct);
            windowMenu->addAction(cascadeAct);
            windowMenu->addSeparator();
            windowMenu->addAction(nextAct);
            windowMenu->addAction(previousAct);
            windowMenu->addAction(separatorAct);

            QList<QWidget *> windows = workspace->windowList();
            separatorAct->setVisible(!windows.isEmpty());

            for (int i = 0; i < windows.size(); ++i) {
                MdiChild *child = qobject_cast<MdiChild *>(windows.at(i));

                QString text;
                if (i < 9) {
                    text = tr("&%1. %2").arg(i + 1)
                                        .arg(child->userFriendlyCurrentFile());
                } else {
                    text = tr("%1. %2").arg(i + 1)
                                       .arg(child->userFriendlyCurrentFile());
                }
                QAction *action  = windowMenu->addAction(text);
                action->setCheckable(true);
                action ->setChecked(child == activeMdiChild());
                connect(action, SIGNAL(triggered()), windowMapper, SLOT(map()));
                windowMapper->setMapping(action, child);
            }
        }

        MdiChild *MainWindow::createMdiChild()
        {
            MdiChild *child = new MdiChild;
            workspace->addWindow(child);

            connect(child, SIGNAL(copyAvailable(bool)),
                    cutAct, SLOT(setEnabled(bool)));
            connect(child, SIGNAL(copyAvailable(bool)),
                    copyAct, SLOT(setEnabled(bool)));

            return child;
        }

        void MainWindow::createActions()
        {
            newAct = new QAction(QIcon(":/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(QIcon(":/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(QIcon(":/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()), qApp, SLOT(closeAllWindows()));

            cutAct = new QAction(QIcon(":/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()), this, SLOT(cut()));

            copyAct = new QAction(QIcon(":/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()), this, SLOT(copy()));

            pasteAct = new QAction(QIcon(":/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()), this, SLOT(paste()));

            closeAct = new QAction(tr("Cl&ose"), this);
            closeAct->setShortcut(tr("Ctrl+F4"));
            closeAct->setStatusTip(tr("Close the active window"));
            connect(closeAct, SIGNAL(triggered()),
                    workspace, SLOT(closeActiveWindow()));

            closeAllAct = new QAction(tr("Close &All"), this);
            closeAllAct->setStatusTip(tr("Close all the windows"));
            connect(closeAllAct, SIGNAL(triggered()),
                    workspace, SLOT(closeAllWindows()));

            tileAct = new QAction(tr("&Tile"), this);
            tileAct->setStatusTip(tr("Tile the windows"));
            connect(tileAct, SIGNAL(triggered()), workspace, SLOT(tile()));

            cascadeAct = new QAction(tr("&Cascade"), this);
            cascadeAct->setStatusTip(tr("Cascade the windows"));
            connect(cascadeAct, SIGNAL(triggered()), workspace, SLOT(cascade()));

            nextAct = new QAction(tr("Ne&xt"), this);
            nextAct->setShortcut(tr("Ctrl+F6"));
            nextAct->setStatusTip(tr("Move the focus to the next window"));
            connect(nextAct, SIGNAL(triggered()),
                    workspace, SLOT(activateNextWindow()));

            previousAct = new QAction(tr("Pre&vious"), this);
            previousAct->setShortcut(tr("Ctrl+Shift+F6"));
            previousAct->setStatusTip(tr("Move the focus to the previous "
                                         "window"));
            connect(previousAct, SIGNAL(triggered()),
                    workspace, SLOT(activatePreviousWindow()));

            separatorAct = new QAction(this);
            separatorAct->setSeparator(true);

            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()));
        }

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

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

            windowMenu = menuBar()->addMenu(tr("&Window"));
            connect(windowMenu, SIGNAL(aboutToShow()), this, SLOT(updateWindowMenu()));

            menuBar()->addSeparator();

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

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

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

        void MainWindow::createStatusBar()
        {
            statusBar()->showMessage(tr("Ready"));
        }

        void MainWindow::readSettings()
        {
            QSettings settings("Trolltech", "MDI Example");
            QPoint pos = settings.value("pos", QPoint(200, 200)).toPoint();
            QSize size = settings.value("size", QSize(400, 400)).toSize();
            move(pos);
            resize(size);
        }

        void MainWindow::writeSettings()
        {
            QSettings settings("Trolltech", "MDI Example");
            settings.setValue("pos", pos());
            settings.setValue("size", size());
        }

        MdiChild *MainWindow::activeMdiChild()
        {
            return qobject_cast<MdiChild *>(workspace->activeWindow());
        }

        MdiChild *MainWindow::findMdiChild(const QString &fileName)
        {
            QString canonicalFilePath = QFileInfo(fileName).canonicalFilePath();

            foreach (QWidget *window, workspace->windowList()) {
                MdiChild *mdiChild = qobject_cast<MdiChild *>(window);
                if (mdiChild->currentFile() == canonicalFilePath)
                    return mdiChild;
            }
            return 0;
        }