dragwidget.cpp Example File
draganddrop/draggabletext/dragwidget.cpp
#include <QtWidgets>
#include "dragwidget.h"
static QLabel *createDragLabel(const QString &text, QWidget *parent)
{
QLabel *label = new QLabel(text, parent);
label->setAutoFillBackground(true);
label->setFrameShape(QFrame::Panel);
label->setFrameShadow(QFrame::Raised);
return label;
}
static QString hotSpotMimeDataKey() { return QStringLiteral("application/x-hotspot"); }
DragWidget::DragWidget(QWidget *parent)
: QWidget(parent)
{
QFile dictionaryFile(QStringLiteral(":/dictionary/words.txt"));
dictionaryFile.open(QIODevice::ReadOnly);
QTextStream inputStream(&dictionaryFile);
int x = 5;
int y = 5;
while (!inputStream.atEnd()) {
QString word;
inputStream >> word;
if (!word.isEmpty()) {
QLabel *wordLabel = createDragLabel(word, this);
wordLabel->move(x, y);
wordLabel->show();
wordLabel->setAttribute(Qt::WA_DeleteOnClose);
x += wordLabel->width() + 2;
if (x >= 245) {
x = 5;
y += wordLabel->height() + 2;
}
}
}
setAcceptDrops(true);
setMinimumSize(400, qMax(200, y));
setWindowTitle(tr("Draggable Text"));
}
void DragWidget::dragEnterEvent(QDragEnterEvent *event)
{
if (event->mimeData()->hasText()) {
if (event->source() == this) {
event->setDropAction(Qt::MoveAction);
event->accept();
} else {
event->acceptProposedAction();
}
} else {
event->ignore();
}
}
void DragWidget::dropEvent(QDropEvent *event)
{
if (event->mimeData()->hasText()) {
const QMimeData *mime = event->mimeData();
QStringList pieces = mime->text().split(QRegularExpression(QStringLiteral("\\s+")),
QString::SkipEmptyParts);
QPoint position = event->pos();
QPoint hotSpot;
QByteArrayList hotSpotPos = mime->data(hotSpotMimeDataKey()).split(' ');
if (hotSpotPos.size() == 2) {
hotSpot.setX(hotSpotPos.first().toInt());
hotSpot.setY(hotSpotPos.last().toInt());
}
for (const QString &piece : pieces) {
QLabel *newLabel = createDragLabel(piece, this);
newLabel->move(position - hotSpot);
newLabel->show();
newLabel->setAttribute(Qt::WA_DeleteOnClose);
position += QPoint(newLabel->width(), 0);
}
if (event->source() == this) {
event->setDropAction(Qt::MoveAction);
event->accept();
} else {
event->acceptProposedAction();
}
} else {
event->ignore();
}
for (QWidget *widget : findChildren<QWidget *>()) {
if (!widget->isVisible())
widget->deleteLater();
}
}
void DragWidget::mousePressEvent(QMouseEvent *event)
{
QLabel *child = qobject_cast<QLabel*>(childAt(event->pos()));
if (!child)
return;
QPoint hotSpot = event->pos() - child->pos();
QMimeData *mimeData = new QMimeData;
mimeData->setText(child->text());
mimeData->setData(hotSpotMimeDataKey(),
QByteArray::number(hotSpot.x()) + ' ' + QByteArray::number(hotSpot.y()));
qreal dpr = window()->windowHandle()->devicePixelRatio();
QPixmap pixmap(child->size() * dpr);
pixmap.setDevicePixelRatio(dpr);
child->render(&pixmap);
QDrag *drag = new QDrag(this);
drag->setMimeData(mimeData);
drag->setPixmap(pixmap);
drag->setHotSpot(hotSpot);
Qt::DropAction dropAction = drag->exec(Qt::CopyAction | Qt::MoveAction, Qt::CopyAction);
if (dropAction == Qt::MoveAction)
child->close();
}