Drag and drop between model views

[wysota]

Unfortunately, rewriting startDrag is a little bit of work. Thanks again for the help.

Copy and paste it from Qt sources and add the lines you need.

[larry104]

Hmmm, that might be embarrissing for me (after all I'm QT beginner) but I get compile errors when I just copy it.

void QAbstractItemView::startDrag(Qt::DropActions supportedActions)
{
    Q_D(QAbstractItemView);
    QModelIndexList indexes = selectedIndexes();
    if (indexes.count() > 0) {
        // setup pixmap
        QRect rect = visualRect(indexes.at(0));
        QList<QRect> rects;
        for (int i = 0; i < indexes.count(); ++i) {
            rects.append(visualRect(indexes.at(i)));
            rect |= rects.at(i);
        }
        rect = rect.intersect(d->viewport->rect());
        QPixmap pixmap(rect.size());
        pixmap.fill(palette().base().color());
        QPainter painter(&pixmap);
        QStyleOptionViewItem option = viewOptions();
        option.state |= QStyle::State_Selected;
        for (int j = 0; j < indexes.count(); ++j) {
            option.rect = QRect(rects.at(j).topLeft() - rect.topLeft(),
                                rects.at(j).size());
            itemDelegate()->paint(&painter, option, indexes.at(j));
        }
        painter.end();
        // create drag object
        QDrag *drag = new QDrag(this);
        drag->setPixmap(pixmap);
        drag->setMimeData(model()->mimeData(indexes));
        drag->setHotSpot(d->viewport->mapFromGlobal(QCursor::pos()) - rect.topLeft());
        if (drag->start(supportedActions) == Qt::MoveAction)
            d->removeSelectedRows();
    }
}

void QAbstractItemView::startDrag(Qt::DropActions supportedActions)
{
    Q_D(QAbstractItemView);
    QModelIndexList indexes = selectedIndexes();
    if (indexes.count() > 0) {
        // setup pixmap
        QRect rect = visualRect(indexes.at(0));
        QList<QRect> rects;
        for (int i = 0; i < indexes.count(); ++i) {
            rects.append(visualRect(indexes.at(i)));
            rect |= rects.at(i);
        }
        rect = rect.intersect(d->viewport->rect());
        QPixmap pixmap(rect.size());
        pixmap.fill(palette().base().color());
        QPainter painter(&pixmap);
        QStyleOptionViewItem option = viewOptions();
        option.state |= QStyle::State_Selected;
        for (int j = 0; j < indexes.count(); ++j) {
            option.rect = QRect(rects.at(j).topLeft() - rect.topLeft(),
                                rects.at(j).size());
            itemDelegate()->paint(&painter, option, indexes.at(j));
        }
        painter.end();
        // create drag object
        QDrag *drag = new QDrag(this);
        drag->setPixmap(pixmap);
        drag->setMimeData(model()->mimeData(indexes));
        drag->setHotSpot(d->viewport->mapFromGlobal(QCursor::pos()) - rect.topLeft());
        if (drag->start(supportedActions) == Qt::MoveAction)
            d->removeSelectedRows();
    }
}

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../../../qt/qt-4.1.4/include/QtGui/qtableview.h: In member function `virtual
   void MyTableView::startDrag(QFlags<Qt::DropAction>)':
../../../qt/qt-4.1.4/include/QtGui/qtableview.h:134: `QTableViewPrivate*
   QTableView::d_func()' is private
mytableview.cpp:43: within this context
mytableview.cpp:43: cannot convert `QTableViewPrivate*' to `
   QAbstractItemViewPrivate* const' in initialization
mytableview.cpp:53: invalid use of undefined type `struct
   QAbstractItemViewPrivate'
../../../qt/qt-4.1.4/include/QtGui/qabstractitemview.h:41: forward declaration
   of `struct QAbstractItemViewPrivate'
mytableview.cpp:69: invalid use of undefined type `struct
   QAbstractItemViewPrivate'
../../../qt/qt-4.1.4/include/QtGui/qabstractitemview.h:41: forward declaration
   of `struct QAbstractItemViewPrivate'
mytableview.cpp:71: invalid use of undefined type `struct
   QAbstractItemViewPrivate'
../../../qt/qt-4.1.4/include/QtGui/qabstractitemview.h:41: forward declaration
   of `struct QAbstractItemViewPrivate'
make: *** [mytableview.o] Error 1

../../../qt/qt-4.1.4/include/QtGui/qtableview.h: In member function `virtual
   void MyTableView::startDrag(QFlags<Qt::DropAction>)':
../../../qt/qt-4.1.4/include/QtGui/qtableview.h:134: `QTableViewPrivate*
   QTableView::d_func()' is private
mytableview.cpp:43: within this context
mytableview.cpp:43: cannot convert `QTableViewPrivate*' to `
   QAbstractItemViewPrivate* const' in initialization
mytableview.cpp:53: invalid use of undefined type `struct
   QAbstractItemViewPrivate'
../../../qt/qt-4.1.4/include/QtGui/qabstractitemview.h:41: forward declaration
   of `struct QAbstractItemViewPrivate'
mytableview.cpp:69: invalid use of undefined type `struct
   QAbstractItemViewPrivate'
../../../qt/qt-4.1.4/include/QtGui/qabstractitemview.h:41: forward declaration
   of `struct QAbstractItemViewPrivate'
mytableview.cpp:71: invalid use of undefined type `struct
   QAbstractItemViewPrivate'
../../../qt/qt-4.1.4/include/QtGui/qabstractitemview.h:41: forward declaration
   of `struct QAbstractItemViewPrivate'
make: *** [mytableview.o] Error 1

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[wysota]

You can't use private components of Qt classes as they are not accessible, so you have to think a workaround for using Q_D and d->. It shouldn't be too hard as d->viewport should be available as viewport() and you can remove the selected rows without using the d->removeSelectedRows() call if you need that functionality. And when you won't be using "d" anymore, you can remove the Q_D() call.

[larry104]

Works perfect now - thanks again so much for all the help.