TreeView Shows my data not correctly. What is wrong?

[Kofr]

Here is the function of adding a child

bool TreeModel::addChild(const QVariant &data, const QModelIndex &parent)
{
    Task *parentTask;
    if (!parent.isValid()){

        qDebug() << "addChild() - parent is not valid";
        parentTask = rootItem;
    }
    else
        parentTask = static_cast<Task*>(parent.internalPointer());

    Task *childTask = new Task(data, parentTask);
    qDebug() << QString::number((int)childTask);///

    int childCount = childTask->childCount();
    emit beginInsertRows(parent, childCount, childCount);
    parentTask->appendChild(childTask);

    emit endInsertRows();
    //emit dataChanged(parent, parent);

    return true;

}

In some situations calling this function from QML makes a mess with Indexes in QML. It start show wrong items or invalid items, especially when Parent has tasks with children (2 levels tree).
What is wrong?

[p3c0]

@Kofr You can't emit beginInsertRows and endInsertRows. They are not signals.