Qt 4.0: dragwidget.cpp Example File (draganddrop/draggabletext/dragwidget.cpp)

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# dragwidget.cpp Example File
draganddrop/draggabletext/dragwidget.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
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    ** review the following information:
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        **
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        #include <QtGui>

        #include "draglabel.h"
        #include "dragwidget.h"

        DragWidget::DragWidget(QWidget *parent)
            : QWidget(parent)
        {
            QFile dictionaryFile(":/dictionary/words.txt");
            dictionaryFile.open(QIODevice::ReadOnly);
            QTextStream inputStream(&dictionaryFile);

            int x = 5;
            int y = 5;

            while (!inputStream.atEnd()) {
                QString word;
                inputStream >> word;
                if (!word.isEmpty()) {
                    DragLabel *wordLabel = new DragLabel(word, this);
                    wordLabel->move(x, y);
                    wordLabel->show();
                    x += wordLabel->width() + 2;
                    if (x >= 195) {
                        x = 5;
                        y += wordLabel->height() + 2;
                    }
                }
            }

            QPalette newPalette = palette();
            newPalette.setColor(QPalette::Background, Qt::white);
            setPalette(newPalette);

            setAcceptDrops(true);
            setMinimumSize(400, qMax(200, y));
            setWindowTitle(tr("Draggable Text"));
        }

        void DragWidget::dragEnterEvent(QDragEnterEvent *event)
        {
            if (event->mimeData()->hasText())
                event->acceptProposedAction();
            else
                event->ignore();
        }

        void DragWidget::dropEvent(QDropEvent *event)
        {
            if (event->mimeData()->hasText()) {
                QStringList pieces = event->mimeData()->text().split(QRegExp("\\s+"),
                                     QString::SkipEmptyParts);
                QPoint position = event->pos();

                foreach (QString piece, pieces) {
                    DragLabel *newLabel = new DragLabel(piece, this);
                    newLabel->move(position);
                    newLabel->show();

                    position += QPoint(newLabel->width(), 0);
                }

                if (children().contains(event->source())) {
                    event->setDropAction(Qt::MoveAction);
                    event->accept();
                } else {
                    event->acceptProposedAction();
                }
            } else {
                event->ignore();
            }
        }