editor.cpp

QT4 gui programming的随书光盘

#include <QtGui>

#include "editor.h"

Editor::Editor(QWidget *parent)
    : QTextEdit(parent)
{
    action = new QAction(this);
    action->setCheckable(true);
    connect(action, SIGNAL(triggered()), this, SLOT(show()));
    connect(action, SIGNAL(triggered()), this, SLOT(setFocus()));

    isUntitled = true;

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

    setWindowIcon(QPixmap(":/images/document.png"));
    setWindowTitle("[*]");
    setAttribute(Qt::WA_DeleteOnClose);
}

void Editor::newFile()
{
    static int documentNumber = 1;

    curFile = tr("document%1.txt").arg(documentNumber);
    setWindowTitle(curFile + "[*]");
    action->setText(curFile);
    isUntitled = true;
    ++documentNumber;
}

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

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

    return saveFile(fileName);
}

QSize Editor::sizeHint() const
{
    return QSize(72 * fontMetrics().width('x'),
                 25 * fontMetrics().lineSpacing());
}

Editor *Editor::open(QWidget *parent)
{
    QString fileName =
            QFileDialog::getOpenFileName(parent, tr("Open"), ".");
    if (fileName.isEmpty())
        return 0;

    return openFile(fileName, parent);
}

Editor *Editor::openFile(const QString &fileName, QWidget *parent)
{
    Editor *editor = new Editor(parent);
    if (editor->readFile(fileName)) {
        editor->setCurrentFile(fileName);
        return editor;
    } else {
        delete editor;
        return 0;
    }
}

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

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

bool Editor::okToContinue()
{
    if (document()->isModified()) {
        int r = QMessageBox::warning(this, tr("MDI Editor"),
                        tr("File %1 has been modified.\n"
                           "Do you want to save your changes?")
                        .arg(strippedName(curFile)),
                        QMessageBox::Yes | QMessageBox::No
                        | QMessageBox::Cancel);
        if (r == QMessageBox::Yes) {
            return save();
        } else if (r == QMessageBox::Cancel) {
            return false;
        }
    }
    return true;
}

bool Editor::saveFile(const QString &fileName)
{
    if (writeFile(fileName)) {
        setCurrentFile(fileName);
        return true;
    } else {
        return false;
    }
}

void Editor::setCurrentFile(const QString &fileName)
{
    curFile = fileName;
    isUntitled = false;
    action->setText(strippedName(curFile));
    document()->setModified(false);
    setWindowTitle(strippedName(curFile) + "[*]");
    setWindowModified(false);
}

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

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

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

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

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