Source code
Revision control
Copy as Markdown
// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#include <QtGui>
#include "dragwidget.h"
DragWidget::DragWidget(QWidget *parent)
: QFrame(parent)
{
setFrameStyle(QFrame::StyledPanel | QFrame::Sunken);
dragDropLabel = new QLabel("", this);
dragDropLabel->setAlignment(Qt::AlignHCenter);
QHBoxLayout *layout = new QHBoxLayout(this);
layout->addStretch(0);
layout->addWidget(dragDropLabel);
layout->addStretch(0);
setAcceptDrops(true);
}
// Accept all actions, but deal with them separately later.
//! [0]
void DragWidget::dragEnterEvent(QDragEnterEvent *event)
{
event->acceptProposedAction();
}
//! [0]
//! [1]
void DragWidget::dropEvent(QDropEvent *event)
{
if (event->source() == this && event->possibleActions() & Qt::MoveAction)
return;
//! [1]
//! [2]
if (event->proposedAction() == Qt::MoveAction) {
event->acceptProposedAction();
// Process the data from the event.
//! [2]
emit dragResult(tr("The data was moved here."));
//! [3]
} else if (event->proposedAction() == Qt::CopyAction) {
event->acceptProposedAction();
// Process the data from the event.
//! [3]
emit dragResult(tr("The data was copied here."));
//! [4]
} else {
// Ignore the drop.
return;
}
//! [4]
// End of quote
emit mimeTypes(event->mimeData()->formats());
setData(event->mimeData()->formats()[0],
event->mimeData()->data(event->mimeData()->formats()[0]));
//! [5]
}
//! [5]
//! [6]
void DragWidget::mousePressEvent(QMouseEvent *event)
{
if (event->button() == Qt::LeftButton)
dragStartPosition = event->pos();
}
//! [6]
//! [7]
void DragWidget::mouseMoveEvent(QMouseEvent *event)
{
if (!(event->buttons() & Qt::LeftButton))
return;
if ((event->pos() - dragStartPosition).manhattanLength()
< QApplication::startDragDistance())
return;
QDrag *drag = new QDrag(this);
QMimeData *mimeData = new QMimeData;
mimeData->setData(mimeType, data);
drag->setMimeData(mimeData);
Qt::DropAction dropAction = drag->exec(Qt::CopyAction | Qt::MoveAction);
//! [7]
switch (dropAction) {
case Qt::CopyAction:
emit dragResult(tr("The text was copied."));
break;
case Qt::MoveAction:
emit dragResult(tr("The text was moved."));
break;
default:
emit dragResult(tr("Unknown action."));
break;
}
//! [8]
}
//! [8]
void DragWidget::setData(const QString &mimetype, const QByteArray &newData)
{
mimeType = mimetype;
data = QByteArray(newData);
dragDropLabel->setText(tr("%1 bytes").arg(data.size()));
QStringList formats;
formats << mimetype;
emit mimeTypes(formats);
}