dragwidget.cpp Example File

draganddrop/draggableicons/dragwidget.cpp
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#include <QtWidgets> #include "dragwidget.h" 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(10, 10); boatIcon->show(); boatIcon->setAttribute(Qt::WA_DeleteOnClose); QLabel *carIcon = new QLabel(this); carIcon->setPixmap(QPixmap(":/images/car.png")); carIcon->move(100, 10); carIcon->show(); carIcon->setAttribute(Qt::WA_DeleteOnClose); QLabel *houseIcon = new QLabel(this); houseIcon->setPixmap(QPixmap(":/images/house.png")); houseIcon->move(10, 80); houseIcon->show(); houseIcon->setAttribute(Qt::WA_DeleteOnClose); } 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(); } } 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()); QMimeData *mimeData = new QMimeData; mimeData->setData("application/x-dnditemdata", itemData); QDrag *drag = new QDrag(this); drag->setMimeData(mimeData); drag->setPixmap(pixmap); drag->setHotSpot(event->pos() - child->pos()); 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); } }