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#include <QtGui>

#include "dragwidget.h"

//! [0]

DragWidget::DragWidget(QWidget *parent)

    : QFrame(parent)

{

    setMinimumSize(200, 200);

    setFrameStyle(QFrame::Sunken | QFrame::StyledPanel);

    setAcceptDrops(true);

    QLabel *boatIcon = new QLabel(this);

    boatIcon->setPixmap(QPixmap(":/images/boat.png"));

    boatIcon->move(20, 20);

    boatIcon->show();

    boatIcon->setAttribute(Qt::WA_DeleteOnClose);

    QLabel *carIcon = new QLabel(this);

    carIcon->setPixmap(QPixmap(":/images/car.png"));

    carIcon->move(120, 20);

    carIcon->show();

    carIcon->setAttribute(Qt::WA_DeleteOnClose);

    QLabel *houseIcon = new QLabel(this);

    houseIcon->setPixmap(QPixmap(":/images/house.png"));

    houseIcon->move(20, 120);

    houseIcon->show();

    houseIcon->setAttribute(Qt::WA_DeleteOnClose);

}

//! [0]

void DragWidget::dragEnterEvent(QDragEnterEvent *event)

{

    if (event->mimeData()->hasFormat("application/x-dnditemdata")) {

        if (event->source() == this) {

            event->setDropAction(Qt::MoveAction);

            event->accept();

        } else {

            event->acceptProposedAction();

        }

    } else {

        event->ignore();

    }

}

void DragWidget::dragMoveEvent(QDragMoveEvent *event)

{

    if (event->mimeData()->hasFormat("application/x-dnditemdata")) {

        if (event->source() == this) {

            event->setDropAction(Qt::MoveAction);

            event->accept();

        } else {

            event->acceptProposedAction();

        }

    } else {

        event->ignore();

    }

}

void DragWidget::dropEvent(QDropEvent *event)

{

    if (event->mimeData()->hasFormat("application/x-dnditemdata")) {

        QByteArray itemData = event->mimeData()->data("application/x-dnditemdata");

        QDataStream dataStream(&itemData, QIODevice::ReadOnly);

        QPixmap pixmap;

        QPoint offset;

        dataStream >> pixmap >> offset;

        QLabel *newIcon = new QLabel(this);

        newIcon->setPixmap(pixmap);

        newIcon->move(event->pos() - offset);

        newIcon->show();

        newIcon->setAttribute(Qt::WA_DeleteOnClose);

        if (event->source() == this) {

            event->setDropAction(Qt::MoveAction);

            event->accept();

        } else {

            event->acceptProposedAction();

        }

    } else {

        event->ignore();

    }

}

//! [1]

void DragWidget::mousePressEvent(QMouseEvent *event)

{

    QLabel *child = static_cast<QLabel*>(childAt(event->pos()));

    if (!child)

        return;

    QPixmap pixmap = *child->pixmap();

    QByteArray itemData;

    QDataStream dataStream(&itemData, QIODevice::WriteOnly);

    dataStream << pixmap << QPoint(event->pos() - child->pos());

//! [1]

//! [2]

    QMimeData *mimeData = new QMimeData;

    mimeData->setData("application/x-dnditemdata", itemData);

//! [2]

//! [3]

    QDrag *drag = new QDrag(this);

    drag->setMimeData(mimeData);

    drag->setPixmap(pixmap);

    drag->setHotSpot(event->pos() - child->pos());

//! [3]

    QPixmap tempPixmap = pixmap;

    QPainter painter;

    painter.begin(&tempPixmap);

    painter.fillRect(pixmap.rect(), QColor(127, 127, 127, 127));

    painter.end();

    child->setPixmap(tempPixmap);

    if (drag->exec(Qt::CopyAction | Qt::MoveAction, Qt::CopyAction) == Qt::MoveAction)

        child->close();

    else {

        child->show();

        child->setPixmap(pixmap);

    }

}