qtableview (libqt) how do I correctly create a QModelIndex

Question

I'm trying to enter edit mode on a specific cell like this

void MainWindow::on_addButton_released(void) {
    tm->addRow();
    tableView->scrollToBottom();
    int ec=tm->firstWritableColumn();
    int r=tm->rowCount(QModelIndex());
    QModelIndex id = tm->index(r, ec, QModelIndex());
    tableView->setCurrentIndex(id);
    tableView->edit(id);
    qDebug() << "row:" << r << " col:" << ec << "index:" << id;
}

my model creates an index like this

QModelIndex TableModel::index(int row,int column,QModelIndex parent) const {
    Q_UNUSED(parent);
    return createIndex(row,column,0);
}

the debug output looks like this

row: 9  col: 1 index: QModelIndex(9,1,0x0,TableModel(0xbf3f50) )  

I'm fairly sure that the index is somehow invalid as setCurrentIndex doesn't seem to be working

Answer 1

OMG! ground swallow me up!

row numbers start with row 0, I needed to do

int r=tm->rowCount(QModelIndex())-1;
QModelIndex id = tm->index(r, ec,QModelIndex());