Qt Reference Documentation

pieceslist.cpp Example File

draganddrop/puzzle/pieceslist.cpp
 /****************************************************************************
 **
 ** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
 ** All rights reserved.
 ** Contact: Nokia Corporation (qt-info@nokia.com)
 **
 ** This file is part of the examples of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:BSD$
 ** You may use this file under the terms of the BSD license as follows:
 **
 ** "Redistribution and use in source and binary forms, with or without
 ** modification, are permitted provided that the following conditions are
 ** met:
 **   * Redistributions of source code must retain the above copyright
 **     notice, this list of conditions and the following disclaimer.
 **   * Redistributions in binary form must reproduce the above copyright
 **     notice, this list of conditions and the following disclaimer in
 **     the documentation and/or other materials provided with the
 **     distribution.
 **   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
 **     the names of its contributors may be used to endorse or promote
 **     products derived from this software without specific prior written
 **     permission.
 **
 ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #include <QtGui>

 #include "pieceslist.h"

 PiecesList::PiecesList(QWidget *parent)
     : QListWidget(parent)
 {
     setDragEnabled(true);
     setViewMode(QListView::IconMode);
     setIconSize(QSize(60, 60));
     setSpacing(10);
     setAcceptDrops(true);
     setDropIndicatorShown(true);
 }

 void PiecesList::dragEnterEvent(QDragEnterEvent *event)
 {
     if (event->mimeData()->hasFormat("image/x-puzzle-piece"))
         event->accept();
     else
         event->ignore();
 }

 void PiecesList::dragMoveEvent(QDragMoveEvent *event)
 {
     if (event->mimeData()->hasFormat("image/x-puzzle-piece")) {
         event->setDropAction(Qt::MoveAction);
         event->accept();
     } else
         event->ignore();
 }

 void PiecesList::dropEvent(QDropEvent *event)
 {
     if (event->mimeData()->hasFormat("image/x-puzzle-piece")) {
         QByteArray pieceData = event->mimeData()->data("image/x-puzzle-piece");
         QDataStream dataStream(&pieceData, QIODevice::ReadOnly);
         QPixmap pixmap;
         QPoint location;
         dataStream >> pixmap >> location;

         addPiece(pixmap, location);

         event->setDropAction(Qt::MoveAction);
         event->accept();
     } else
         event->ignore();
 }

 void PiecesList::addPiece(QPixmap pixmap, QPoint location)
 {
     QListWidgetItem *pieceItem = new QListWidgetItem(this);
     pieceItem->setIcon(QIcon(pixmap));
     pieceItem->setData(Qt::UserRole, QVariant(pixmap));
     pieceItem->setData(Qt::UserRole+1, location);
     pieceItem->setFlags(Qt::ItemIsEnabled | Qt::ItemIsSelectable
                         | Qt::ItemIsDragEnabled);
 }

 void PiecesList::startDrag(Qt::DropActions /*supportedActions*/)
 {
     QListWidgetItem *item = currentItem();

     QByteArray itemData;
     QDataStream dataStream(&itemData, QIODevice::WriteOnly);
     QPixmap pixmap = qVariantValue<QPixmap>(item->data(Qt::UserRole));
     QPoint location = item->data(Qt::UserRole+1).toPoint();

     dataStream << pixmap << location;

     QMimeData *mimeData = new QMimeData;
     mimeData->setData("image/x-puzzle-piece", itemData);

     QDrag *drag = new QDrag(this);
     drag->setMimeData(mimeData);
     drag->setHotSpot(QPoint(pixmap.width()/2, pixmap.height()/2));
     drag->setPixmap(pixmap);

     if (drag->exec(Qt::MoveAction) == Qt::MoveAction)
         delete takeItem(row(item));
 }
X

Thank you for giving your feedback.

Make sure it is related to this specific page. For more general bugs and requests, please use the Qt Bug Tracker.

[0]; s.parentNode.insertBefore(ga, s); })();