QTtableView how to display aggregate in the bottom

[kef]

...does your override of rowCount() ever get called?

Yes, it gets called properly. I modified my override to confirm:

int DecoratorProxyModel::rowCount(const QModelIndex &parent) const
{
    qDebug() << "proxy rowCount() call, sourceModel():"  << sourceModel()->rowCount(parent) << "base class rowCount():" << QSortFilterProxyModel::rowCount(parent);
    qDebug() << "modified rowCount() response:" << sourceModel()->rowCount(parent) + 1;
    return sourceModel()->rowCount(parent) + 1;
//    return QSortFilterProxyModel::rowCount(parent) + 1;
}

int DecoratorProxyModel::rowCount(const QModelIndex &parent) const
{
    qDebug() << "proxy rowCount() call, sourceModel():"  << sourceModel()->rowCount(parent) << "base class rowCount():" << QSortFilterProxyModel::rowCount(parent);
    qDebug() << "modified rowCount() response:" << sourceModel()->rowCount(parent) + 1;
    return sourceModel()->rowCount(parent) + 1;
//    return QSortFilterProxyModel::rowCount(parent) + 1;
}

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Both implementations, using the source model rowCount() and using the base class rowCount() report the same number of rows.

Debug output:

> Source model initModel(), rows: 7
proxy rowCount() call, sourceModel()->rowC: 7 base class rowCount(): 7
modified rowCount() response: 8
proxy rowCount() call, sourceModel(): 7 base class rowCount(): 7
modified rowCount() response: 8
proxy rowCount() call, sourceModel(): 7 base class rowCount(): 7
modified rowCount() response: 8
proxy rowCount() call, sourceModel(): 7 base class rowCount(): 7
modified rowCount() response: 8
proxy rowCount() call, sourceModel(): 7 base class rowCount(): 7
modified rowCount() response: 8
proxy rowCount() call, sourceModel(): 7 base class rowCount(): 7
modified rowCount() response: 8
proxy rowCount() call, sourceModel(): 7 base class rowCount(): 7
modified rowCount() response: 8

> Source model initModel(), rows: 7
proxy rowCount() call, sourceModel()->rowC: 7 base class rowCount(): 7
modified rowCount() response: 8
proxy rowCount() call, sourceModel(): 7 base class rowCount(): 7
modified rowCount() response: 8
proxy rowCount() call, sourceModel(): 7 base class rowCount(): 7
modified rowCount() response: 8
proxy rowCount() call, sourceModel(): 7 base class rowCount(): 7
modified rowCount() response: 8
proxy rowCount() call, sourceModel(): 7 base class rowCount(): 7
modified rowCount() response: 8
proxy rowCount() call, sourceModel(): 7 base class rowCount(): 7
modified rowCount() response: 8
proxy rowCount() call, sourceModel(): 7 base class rowCount(): 7
modified rowCount() response: 8

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Have you also overridden the QSortFilterProxyModel::filterAcceptsRow() protected method?

No, I didn't touch the QSortFilterProxyModel::filterAcceptsRow() method. In fact, I've read Qt docs and found out that it is better to use QIdentityProxyModel if I just want to modify the output. So, I tried subclassing identity proxy overriding only rowCount() and data() methods with the same code I did for sortfilter proxy, but it didn't help, the view doesn't call the data() method for that additional virtual rowCount()+1 row.

I also tried fiddling with the QSortFilterProxyModel::flags(), but seems like it doesn't get called for the virtual row either.

Qt::ItemFlags DecoratorProxyModel::flags(const QModelIndex &index) const
{
    qint32 row = index.row();
    qint32 col = index.column();
    qDebug() << "flags():" << row << col;
    return Qt::ItemIsSelectable | Qt::ItemIsEnabled;
}

Qt::ItemFlags DecoratorProxyModel::flags(const QModelIndex &index) const
{
    qint32 row = index.row();
    qint32 col = index.column();
    qDebug() << "flags():" << row << col;
    return Qt::ItemIsSelectable | Qt::ItemIsEnabled;
}

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And I thought I understood how Qt's Model View framework works :-)