dragwidget.cpp Example File

draganddrop/fridgemagnets/dragwidget.cpp
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#include "draglabel.h" #include "dragwidget.h" #include <QtWidgets> static inline QString fridgetMagnetsMimeType() { return QStringLiteral("application/x-fridgemagnet"); } DragWidget::DragWidget(QWidget *parent) : QWidget(parent) { QFile dictionaryFile(QStringLiteral(":/dictionary/words.txt")); dictionaryFile.open(QFile::ReadOnly); QTextStream inputStream(&dictionaryFile); int x = 5; int y = 5; while (!inputStream.atEnd()) { QString word; inputStream >> word; if (!word.isEmpty()) { DragLabel *wordLabel = new DragLabel(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; } } } QPalette newPalette = palette(); newPalette.setColor(QPalette::Window, Qt::white); setPalette(newPalette); setMinimumSize(400, qMax(200, y)); setWindowTitle(tr("Fridge Magnets")); setAcceptDrops(true); } void DragWidget::dragEnterEvent(QDragEnterEvent *event) { if (event->mimeData()->hasFormat(fridgetMagnetsMimeType())) { if (children().contains(event->source())) { event->setDropAction(Qt::MoveAction); event->accept(); } else { event->acceptProposedAction(); } } else if (event->mimeData()->hasText()) { event->acceptProposedAction(); } else { event->ignore(); } } void DragWidget::dragMoveEvent(QDragMoveEvent *event) { if (event->mimeData()->hasFormat(fridgetMagnetsMimeType())) { if (children().contains(event->source())) { event->setDropAction(Qt::MoveAction); event->accept(); } else { event->acceptProposedAction(); } } else if (event->mimeData()->hasText()) { event->acceptProposedAction(); } else { event->ignore(); } } void DragWidget::dropEvent(QDropEvent *event) { if (event->mimeData()->hasFormat(fridgetMagnetsMimeType())) { const QMimeData *mime = event->mimeData(); QByteArray itemData = mime->data(fridgetMagnetsMimeType()); QDataStream dataStream(&itemData, QIODevice::ReadOnly); QString text; QPoint offset; dataStream >> text >> offset; DragLabel *newLabel = new DragLabel(text, this); newLabel->move(event->pos() - offset); newLabel->show(); newLabel->setAttribute(Qt::WA_DeleteOnClose); if (event->source() == this) { event->setDropAction(Qt::MoveAction); event->accept(); } else { event->acceptProposedAction(); } } else if (event->mimeData()->hasText()) { QStringList pieces = event->mimeData()->text().split(QRegularExpression(QStringLiteral("\\s+")), QString::SkipEmptyParts); QPoint position = event->pos(); for (const QString &piece : pieces) { DragLabel *newLabel = new DragLabel(piece, this); newLabel->move(position); newLabel->show(); newLabel->setAttribute(Qt::WA_DeleteOnClose); position += QPoint(newLabel->width(), 0); } event->acceptProposedAction(); } else { event->ignore(); } } void DragWidget::mousePressEvent(QMouseEvent *event) { DragLabel *child = static_cast<DragLabel*>(childAt(event->pos())); if (!child) return; QPoint hotSpot = event->pos() - child->pos(); QByteArray itemData; QDataStream dataStream(&itemData, QIODevice::WriteOnly); dataStream << child->labelText() << QPoint(hotSpot); QMimeData *mimeData = new QMimeData; mimeData->setData(fridgetMagnetsMimeType(), itemData); mimeData->setText(child->labelText()); QDrag *drag = new QDrag(this); drag->setMimeData(mimeData); drag->setPixmap(*child->pixmap()); drag->setHotSpot(hotSpot); child->hide(); if (drag->exec(Qt::MoveAction | Qt::CopyAction, Qt::CopyAction) == Qt::MoveAction) child->close(); else child->show(); }

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