- 将自定义数据作为 QByteArray 对象,使用 QMimeData::setData() 函数作为二进制数据存储到 QMimeData 中,然后使用 QMimeData::Data() 读取;
- 继承 QMimeData,重写其中的 formats() 和 retrieveData() 函数操作自定义数据;
- 如果拖放操作仅仅发生在同一个应用程序,可以直接继承 QMimeData,然后使用任意合适的数据结构进行存储。
- void MyTableWidget::mouseMoveEvent(QMouseEvent *event)
- {
- if (event->buttons() & Qt::LeftButton) {
- int distance = (event->pos() - startPos).manhattanLength();
- if (distance >= QApplication::startDragDistance())
- performDrag();
- }
- QTableWidget::mouseMoveEvent(event);
- }
- void MyTableWidget::performDrag()
- {
- QString plainText = selectionAsPlainText();
- if (plainText.isEmpty())
- return;
- QMimeData *mimeData = new QMimeData;
- mimeData->setText(plainText);
- mimeData->setHtml(toHtml(plainText));
- mimeData->setData("text/csv", toCsv(plainText).toUtf8());
- QDrag *drag = new QDrag(this);
- drag->setMimeData(mimeData);
- if (drag->exec(Qt::CopyAction | Qt::MoveAction) == Qt::MoveAction)
- deleteSelection();
- }
- QString MyTableWidget::toCsv(const QString &plainText)
- {
- QString result = plainText;
- result.replace("\\", "\\\\");
- result.replace("\"", "\\\"");
- result.replace("\t", "\", \"");
- result.replace("\n", "\"\n\"");
- result.prepend("\"");
- result.append("\"");
- return result;
- }
- QString MyTableWidget::toHtml(const QString &plainText)
- {
- QString result = Qt::escape(plainText);
- result.replace("\t", "<td>");
- result.replace("\n", "\n<tr><td>");
- result.prepend("<table>\n<tr><td>");
- result.append("\n</table>");
- return result;
- }
Red Green Blue Cyan Yellow Magenta
"Red", "Green", "Blue" "Cyan", "Yellow", "Magenta"
<tr><td>Red<td>Green<td>Blue
<tr><td>Cyan<td>Yellow<td>Magenta
</table>
- void MyTableWidget::dropEvent(QDropEvent *event)
- {
- if (event->mimeData()->hasFormat("text/csv")) {
- QByteArray csvData = event->mimeData()->data("text/csv");
- QString csvText = QString::fromUtf8(csvData);
- // ...
- event->acceptProposedAction();
- } else if (event->mimeData()->hasFormat("text/plain")) {
- QString plainText = event->mimeData()->text();
- // ...
- event->acceptProposedAction();
- }
- }
- class TableMimeData : public QMimeData
- {
- Q_OBJECT
- public:
- TableMimeData(const QTableWidget *tableWidget,
- const QTableWidgetSelectionRange &range);
- const QTableWidget *tableWidget() const { return myTableWidget; }
- QTableWidgetSelectionRange range() const { return myRange; }
- QStringList formats() const;
- protected:
- QVariant retrieveData(const QString &format,
- QVariant::Type preferredType) const;
- private:
- static QString toHtml(const QString &plainText);
- static QString toCsv(const QString &plainText);
- QString text(int row, int column) const;
- QString rangeAsPlainText() const;
- const QTableWidget *myTableWidget;
- QTableWidgetSelectionRange myRange;
- QStringList myFormats;
- };
- TableMimeData::TableMimeData(const QTableWidget *tableWidget,
- const QTableWidgetSelectionRange &range)
- {
- myTableWidget = tableWidget;
- myRange = range;
- myFormats << "text/csv" << "text/html" << "text/plain";
- }
- QStringList TableMimeData::formats() const
- {
- return myFormats;
- }
- QVariant TableMimeData::retrieveData(const QString &format,
- QVariant::Type preferredType) const
- {
- if (format == "text/plain") {
- return rangeAsPlainText();
- } else if (format == "text/csv") {
- return toCsv(rangeAsPlainText());
- } else if (format == "text/html") {
- return toHtml(rangeAsPlainText());
- } else {
- return QMimeData::retrieveData(format, preferredType);
- }
- }
- void MyTableWidget::dropEvent(QDropEvent *event)
- {
- const TableMimeData *tableData =
- qobject_cast<const TableMimeData *>(event->mimeData());
- if (tableData) {
- const QTableWidget *otherTable = tableData->tableWidget();
- QTableWidgetSelectionRange otherRange = tableData->range();
- // ...
- event->acceptProposedAction();
- } else if (event->mimeData()->hasFormat("text/csv")) {
- QByteArray csvData = event->mimeData()->data("text/csv");
- QString csvText = QString::fromUtf8(csvData);
- // ...
- event->acceptProposedAction();
- } else if (event->mimeData()->hasFormat("text/plain")) {
- QString plainText = event->mimeData()->text();
- // ...
- event->acceptProposedAction();
- }
- QTableWidget::mouseMoveEvent(event);
- }