QTreeWidget drag and drop for reordering selects wrong item

Question

After having followed the recommendations given here : QTreeWidget reordering child items by dragging, the dragged item is not selected.

So, quite naturally, I tried to get the dragged item and then call setSelected() on it.

The result is that the item before the correct on is selected.

I subclass QTreeWidget to override dropEvent like this -

QTreeWidgetItem *pItem;
QModelIndex dropIndex = indexAt(pEvent->pos());

if(dropIndex.isValid() == false)
{
    pEvent->setDropAction(Qt::IgnoreAction);
    pEvent->accept();
    return;
}

pItem = this->itemAt(pEvent->pos());
QTreeWidget::dropEvent(pEvent);

How can I get the pointer to the correct QTreeWidgetItem which has been dropped ?

Answer 1

Since the dropped item can "fall" above or below of the target item, you need to manage both situations and calculate the correct index of the moved item. For example:

[..]
virtual void dropEvent(QDropEvent * event)
{
    QModelIndex droppedIndex = indexAt( event->pos() );
    if( !droppedIndex.isValid() )
        return;

    QTreeWidget::dropEvent(event);

    DropIndicatorPosition dp = dropIndicatorPosition();
    if (dp == QAbstractItemView::BelowItem) {
        droppedIndex = droppedIndex.sibling(droppedIndex.row() + 1, // adjust the row number
                                            droppedIndex.column());
    }
    selectionModel()->select(droppedIndex, QItemSelectionModel::Select);
}