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# mainwindow.cpp Example File
mainwindows/sdi/mainwindow.cpp

    /****************************************************************************
    **
    ** Copyright (C) 2004-2006 Trolltech ASA. All rights reserved.
    **
    ** This file is part of the example classes of the Qt Toolkit.
    **
    ** Licensees holding valid Qt Preview licenses may use this file in
    ** accordance with the Qt Preview License Agreement provided with the
    ** Software.
    **
    ** See http://www.trolltech.com/pricing.html or email sales@trolltech.com for
    ** information about Qt Commercial License Agreements.
    **
    ** Contact info@trolltech.com if any conditions of this licensing are
    ** not clear to you.
    **
    ** 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"

    MainWindow::MainWindow()
    {
        init();
        setCurrentFile("");
    }

    MainWindow::MainWindow(const QString &fileName)
    {
        init();
        loadFile(fileName);
    }

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

    void MainWindow::newFile()
    {
        MainWindow *other = new MainWindow;
        other->move(x() + 40, y() + 40);
        other->show();
    }

    void MainWindow::open()
    {
        QString fileName = QFileDialog::getOpenFileName(this);
        if (!fileName.isEmpty()) {
            MainWindow *existing = findMainWindow(fileName);
            if (existing) {
                existing->show();
                existing->raise();
                existing->activateWindow();
                return;
            }

            if (isUntitled && textEdit->document()->isEmpty()
                    && !isWindowModified()) {
                loadFile(fileName);
            } else {
                MainWindow *other = new MainWindow(fileName);
                if (other->isUntitled) {
                    delete other;
                    return;
                }
                other->move(x() + 40, y() + 40);
                other->show();
            }
        }
    }

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

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

        return saveFile(fileName);
    }

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

    void MainWindow::documentWasModified()
    {
        setWindowModified(true);
    }

    void MainWindow::init()
    {
        setAttribute(Qt::WA_DeleteOnClose);

        isUntitled = true;

        textEdit = new QTextEdit;
        setCentralWidget(textEdit);

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

        readSettings();

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

    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()));

        closeAct = new QAction(tr("&Close"), this);
        closeAct->setShortcut(tr("Ctrl+W"));
        closeAct->setStatusTip(tr("Close this window"));
        connect(closeAct, SIGNAL(triggered()), this, SLOT(close()));

        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()), textEdit, 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()), textEdit, 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()), 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()));

        cutAct->setEnabled(false);
        copyAct->setEnabled(false);
        connect(textEdit, SIGNAL(copyAvailable(bool)),
                cutAct, SLOT(setEnabled(bool)));
        connect(textEdit, SIGNAL(copyAvailable(bool)),
                copyAct, SLOT(setEnabled(bool)));
    }

    void MainWindow::createMenus()
    {
        fileMenu = menuBar()->addMenu(tr("&File"));
        fileMenu->addAction(newAct);
        fileMenu->addAction(openAct);
        fileMenu->addAction(saveAct);
        fileMenu->addAction(saveAsAct);
        fileMenu->addSeparator();
        fileMenu->addAction(closeAct);
        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 = 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", "SDI 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", "SDI Example");
        settings.setValue("pos", pos());
        settings.setValue("size", size());
    }

    bool MainWindow::maybeSave()
    {
        if (textEdit->document()->isModified()) {
            QMessageBox::StandardButton ret;
            ret = QMessageBox::warning(this, tr("SDI"),
                         tr("The document has been modified.\n"
                            "Do you want to save your changes?"),
                         QMessageBox::Save | QMessageBox::Discard
                         | QMessageBox::Cancel);
            if (ret == QMessageBox::Save)
                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 | QFile::Text)) {
            QMessageBox::warning(this, tr("SDI"),
                                 tr("Cannot read file %1:\n%2.")
                                 .arg(fileName)
                                 .arg(file.errorString()));
            return;
        }

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

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

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

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

        setCurrentFile(fileName);
        statusBar()->showMessage(tr("File saved"), 2000);
        return true;
    }

    void MainWindow::setCurrentFile(const QString &fileName)
    {
        static int sequenceNumber = 1;

        isUntitled = fileName.isEmpty();
        if (isUntitled) {
            curFile = tr("document%1.txt").arg(sequenceNumber++);
        } else {
            curFile = QFileInfo(fileName).canonicalFilePath();
        }

        textEdit->document()->setModified(false);
        setWindowModified(false);

        setWindowTitle(tr("%1[*] - %2").arg(strippedName(curFile))
                                           .arg(tr("SDI")));
    }

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

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

        foreach (QWidget *widget, qApp->topLevelWidgets()) {
            MainWindow *mainWin = qobject_cast<MainWindow *>(widget);
            if (mainWin && mainWin->curFile == canonicalFilePath)
                return mainWin;
        }
        return 0;
    }