QTableView: When selecting cells, how do I make the first cell selected the current index?

I have a simple class which inherits QTableView and I want the following behavior: when the user selects a few cells, I want the first cell selected to be set as the current index.

So for example if I select from (0, 0) towards (2, 2), when I start typing the text would show up i开发者_JAVA技巧n (0, 0), not (2, 2) which seems to be the default.

I have tried overriding the setSelection function with the following:

void SampleTable::setSelection(const QRect &rect, QItemSelectionModel::SelectionFlags command)
{
    if((command & QItemSelectionModel::Current) != 0)
    {
        QModelIndex curr = indexAt(rect.topLeft());
        selectionModel()->select(curr, QItemSelectionModel::Current);

        command ^= QItemSelectionModel::Current;
    }
    QTableView::setSelection(rect, command);
}

but to no avail. It seems to have something to do with the mouse events, but I can't quite locate the problem in the source code and I'm hoping there's an easier way anyway.

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What are you trying to achieve? If you'd like the user to edit/select a single cell only, use setSelectionBehaviour to force this. Otherwise you could try chinfoo's idea but make sure to communicate the behavior in a way the user is able to understand it (i.e. he's able to see that his edit will change the first cell/row).

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I figured out the problem and how to fix it, but it's not pretty. The problem is in the mouse moved event for a QAbstractItemView. After much debugging and searching through the source code I found this in qabstractitemview.cpp:

void QAbstractItemView::mouseMoveEvent(QMouseEvent *event)
...
if (index.isValid()
        && (index != d->selectionModel->currentIndex())
        && d->isIndexEnabled(index))
    d->selectionModel->setCurrentIndex(index, QItemSelectionModel::NoUpdate);
}

I fixed it by giving my class a QModelIndex member which stores the last location of the top left QModelIndex (set in my overriden version of setSelection like above) and then I overrode the mouseMoveEvent with this:

void SampleTable::mouseMoveEvent(QMouseEvent *event)
{
    QTableView::mouseMoveEvent(event);
    if (state() == ExpandingState || state() == CollapsingState || state() == DraggingState || state() == EditingState)
            return;
    if ((event->buttons() & Qt::LeftButton)) {
        if (m_topLeft.isValid())
        {
            selectionModel()->setCurrentIndex(m_topLeft, QItemSelectionModel::NoUpdate);
        }
    }
}

Not a pretty solution, but it works.

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The QtableWidget class has a signal itemSelectionChanged(), connect it to your custom slot. In that slot, use selectedIndexes() to get all indexes, then use setCurrentIndex() to set the cell which you want to be the current index.