QTableView not displaying check box for column zero

Perdrix

In my TableModel I have defined a flags() mf :

        Qt::ItemFlags flags(const QModelIndex& index) const override
        {
            auto flags = QAbstractTableModel::flags(index);
            if (0 == index.column()) flags |= Qt::ItemIsUserCheckable;
            return flags;
        }

in my data() mf I have:

        if (role == Qt::CheckStateRole)
        {
            if (0 == index.column())
                return file.m_bChecked;
            else return QVariant();

        }

where m_bChecked is of type QT::CheckState

But I never see a check box added to column 0?

Did I miss some crucial step?

Thanks
David

Perdrix

@JonB Thanks for that pointer ... I'll look right away

The code now reads:

            else if (Qt::CheckStateRole == role && 0 == index.column())
            {
                file.m_bChecked = static_cast<Qt::CheckState>(value.toInt());
                emit dataChanged(index, index);
                return true;
            }

which seems to fix the problem ...

Thanks a lot

Christian Ehrlicher

Put a debug statement in your data() / Qt::CheckStateRole and see if you get there. Also make sure m_bChecked is really of type Qt::CheckState.
The flags() is only needed when you want the data to be modified by the user ('UserCheckable')

Perdrix

OK that found the problem quickly enough - there was a spurious return QVariant() before the check for CheckStateRole. <BLUSH>

However, now that's fixed, I cannot change the value of the check box by interacting with it - do I need to write some extra code to allow user interaction with that check box?

Thanks
David

JonB

@Perdrix Check it hits your setData() override, and what happens there?

Perdrix

@JonB Thanks for that pointer ... I'll look right away

The code now reads:

            else if (Qt::CheckStateRole == role && 0 == index.column())
            {
                file.m_bChecked = static_cast<Qt::CheckState>(value.toInt());
                emit dataChanged(index, index);
                return true;
            }

which seems to fix the problem ...

Thanks a lot