Qt 4.0: mainwindow.cpp Example File (tools/codecs/mainwindow.cpp)

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# mainwindow.cpp Example File
tools/codecs/mainwindow.cpp

        /****************************************************************************
        **
        ** Copyright (C) 2004-2005 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 "previewform.h"

        MainWindow::MainWindow()
        {
            textEdit = new QTextEdit;
            textEdit->setLineWrapMode(QTextEdit::NoWrap);
            setCentralWidget(textEdit);

            findCodecs();

            previewForm = new PreviewForm(this);
            previewForm->setCodecList(codecs);

            createActions();
            createMenus();

            setWindowTitle(tr("Codecs"));
            resize(500, 400);
        }

        void MainWindow::open()
        {
            QString fileName = QFileDialog::getOpenFileName(this);
            if (!fileName.isEmpty()) {
                QFile file(fileName);
                if (!file.open(QFile::ReadOnly)) {
                    QMessageBox::warning(this, tr("Codecs"),
                                         tr("Cannot read file %1:\n%2")
                                         .arg(fileName)
                                         .arg(file.errorString()));
                    return;
                }

                QByteArray data = file.readAll();

                previewForm->setEncodedData(data);
                if (previewForm->exec())
                    textEdit->setPlainText(previewForm->decodedString());
            }
        }

        void MainWindow::save()
        {
            QString fileName = QFileDialog::getSaveFileName(this);
            if (!fileName.isEmpty()) {
                QFile file(fileName);
                if (!file.open(QFile::WriteOnly)) {
                    QMessageBox::warning(this, tr("Codecs"),
                                         tr("Cannot write file %1:\n%2")
                                         .arg(fileName)
                                         .arg(file.errorString()));
                    return;
                }

                QAction *action = qobject_cast<QAction *>(sender());
                QByteArray codecName = action->data().toByteArray();

                QTextStream out(&file);
                out.setCodec(codecName);
                out << textEdit->toPlainText();
            }
        }

        void MainWindow::about()
        {
            QMessageBox::about(this, tr("About Codecs"),
                    tr("The <b>Codecs</b> example demonstrates how to read and write "
                       "files using various encodings."));
        }

        void MainWindow::aboutToShowSaveAsMenu()
        {
            QString currentText = textEdit->toPlainText();

            foreach (QAction *action, saveAsActs) {
                QByteArray codecName = action->data().toByteArray();
                QTextCodec *codec = QTextCodec::codecForName(codecName);
                action->setVisible(codec && codec->canEncode(currentText));
            }
        }

        void MainWindow::findCodecs()
        {
            QMap<QString, QTextCodec *> codecMap;
            QRegExp iso8859RegExp("ISO[- ]8859-([0-9]+).*");

            foreach (int mib, QTextCodec::availableMibs()) {
                QTextCodec *codec = QTextCodec::codecForMib(mib);

                QString sortKey = codec->name().toUpper();
                int rank;

                if (sortKey.startsWith("UTF-8")) {
                    rank = 1;
                } else if (sortKey.startsWith("UTF-16")) {
                    rank = 2;
                } else if (iso8859RegExp.exactMatch(sortKey)) {
                    if (iso8859RegExp.cap(1).size() == 1)
                        rank = 3;
                    else
                        rank = 4;
                } else {
                    rank = 5;
                }
                sortKey.prepend(QChar('0' + rank));

                codecMap.insert(sortKey, codec);
            }
            codecs = codecMap.values();
        }

        void MainWindow::createActions()
        {
            openAct = new QAction(tr("&Open..."), this);
            openAct->setShortcut(tr("Ctrl+O"));
            connect(openAct, SIGNAL(triggered()), this, SLOT(open()));

            foreach (QTextCodec *codec, codecs) {
                QString text = tr("%1...").arg(QString(codec->name()));

                QAction *action = new QAction(text, this);
                action->setData(codec->name());
                connect(action, SIGNAL(triggered()), this, SLOT(save()));
                saveAsActs.append(action);
            }

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

            aboutAct = new QAction(tr("&About"), this);
            connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));

            aboutQtAct = new QAction(tr("About &Qt"), this);
            connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));
        }

        void MainWindow::createMenus()
        {
            saveAsMenu = new QMenu(tr("&Save As"), this);
            foreach (QAction *action, saveAsActs)
                saveAsMenu->addAction(action);
            connect(saveAsMenu, SIGNAL(aboutToShow()),
                    this, SLOT(aboutToShowSaveAsMenu()));

            fileMenu = new QMenu(tr("&File"), this);
            fileMenu->addAction(openAct);
            fileMenu->addMenu(saveAsMenu);
            fileMenu->addSeparator();
            fileMenu->addAction(exitAct);

            helpMenu = new QMenu(tr("&Help"), this);
            helpMenu->addAction(aboutAct);
            helpMenu->addAction(aboutQtAct);

            menuBar()->addMenu(fileMenu);
            menuBar()->addSeparator();
            menuBar()->addMenu(helpMenu);
        }