Qt 4.3: dragwidget.cpp Example File (draganddrop/fridgemagnets/dragwidget.cpp)

|  | Home · All Classes · Main Classes · Grouped Classes · Modules · Functions |

# dragwidget.cpp Example File
draganddrop/fridgemagnets/dragwidget.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2005-2008 Trolltech ASA. 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 versions 2.0 or 3.0 as published by the Free Software
    ** Foundation and appearing in the files LICENSE.GPL2 and LICENSE.GPL3
    ** included in the packaging of this file.  Alternatively you may (at
    ** your option) use any later version of the GNU General Public
    ** License if such license has been publicly approved by Trolltech ASA
    ** (or its successors, if any) and the KDE Free Qt Foundation. In
    ** addition, as a special exception, Trolltech gives you certain
    ** additional rights. These rights are described in the Trolltech GPL
    ** Exception version 1.2, which can be found at
    ** http://www.trolltech.com/products/qt/gplexception/ and in the file
    ** GPL_EXCEPTION.txt in this package.
    **
    ** Please review the following information to ensure GNU General
    ** Public Licensing requirements will be met:
    ** http://trolltech.com/products/qt/licenses/licensing/opensource/. If
    ** you are unsure which license is appropriate for your use, please
    ** review the following information:
    ** http://trolltech.com/products/qt/licenses/licensing/licensingoverview
    ** or contact the sales department at sales@trolltech.com.
    **
    ** In addition, as a special exception, Trolltech, as the sole
    ** copyright holder for Qt Designer, grants users of the Qt/Eclipse
    ** Integration plug-in the right for the Qt/Eclipse Integration to
    ** link to functionality provided by Qt Designer and its related
    ** libraries.
    **
    ** This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
    ** INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
    ** A PARTICULAR PURPOSE. Trolltech reserves all rights not expressly
    ** granted herein.
     **
     ** 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 "draglabel.h"
     #include "dragwidget.h"

     DragWidget::DragWidget(QWidget *parent)
         : QWidget(parent)
     {
         QFile dictionaryFile(":/dictionary/words.txt");
         dictionaryFile.open(QFile::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 >= 245) {
                     x = 5;
                     y += wordLabel->height() + 2;
                 }
             }
         }

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

         setMinimumSize(400, qMax(200, y));
         setWindowTitle(tr("Fridge Magnets"));
         setAcceptDrops(true);
     }

     void DragWidget::dragEnterEvent(QDragEnterEvent *event)
     {
         if (event->mimeData()->hasFormat("application/x-fridgemagnet")) {
             if (children().contains(event->source())) {
                 event->setDropAction(Qt::MoveAction);
                 event->accept();
             } else {
                 event->acceptProposedAction();
             }
         } else if (event->mimeData()->hasText()) {
             event->acceptProposedAction();
         } else {
             event->ignore();
         }
     }

     void DragWidget::dragMoveEvent(QDragMoveEvent *event)
     {
         if (event->mimeData()->hasFormat("application/x-fridgemagnet")) {
             if (children().contains(event->source())) {
                 event->setDropAction(Qt::MoveAction);
                 event->accept();
             } else {
                 event->acceptProposedAction();
             }
         } else if (event->mimeData()->hasText()) {
             event->acceptProposedAction();
         } else {
             event->ignore();
         }
     }

     void DragWidget::dropEvent(QDropEvent *event)
     {
         if (event->mimeData()->hasFormat("application/x-fridgemagnet")) {
             const QMimeData *mime = event->mimeData();
             QByteArray itemData = mime->data("application/x-fridgemagnet");
             QDataStream dataStream(&itemData, QIODevice::ReadOnly);

             QString text;
             QPoint offset;
             dataStream >> text >> offset;

             DragLabel *newLabel = new DragLabel(text, this);
             newLabel->move(event->pos() - offset);
             newLabel->show();

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

             event->acceptProposedAction();
         } else {
             event->ignore();
         }
     }