I've created an application that subclasses the QAbstractItemModel to load item from at database and display them in a QTreeview. I store data in a QMap and I've implemented new functions for;

QModelIndex index(int row, int column,const QModelIndex &parent) const;
QModelIndex parent(const QModelIndex &child) const;

int rowCount(const QModelIndex &parent) const;
int columnCount(const QModelIndex &parent) const;
QVariant data(const QModelIndex &index, int role) const;
QVariant headerData(int section, Qt::Orientation orientation, int role) const;

Now I want to change the model from QAbstractItemModel to QStandardItemModel to utilize the sort and findItems functions. I'm changing my implementation class from QAbstractItemModel to QStandardItemModel but now the Qtreeview is empty when I run the code. What going on here?
Does anyone have an example of a QStandardItemModel bieng subclasses (editable) to be used in a QTreeview?

Thanks