#include <QApplication>
#include <QAbstractListModel>
#include <QStringList>
#include <QListView>

class ListModel : public QAbstractListModel
{
public:
    ListModel(QObject * parent = nullptr)
        : QAbstractListModel {parent}
        , list {"A", "B", "C", "D"}
    {
    }

protected:
    int rowCount(QModelIndex const& index = QModelIndex {}) const override
    {
        return index.isValid() ? 0 : list.size();
    }

    QVariant data(QModelIndex const& index, int role) const override
    {
        QVariant result;
        if (Qt::DisplayRole == role) result = list[index.row()];
        return result;
    }

    Qt::ItemFlags flags(QModelIndex const& index) const override
    {
        auto flags = QAbstractListModel::flags(index) | Qt::ItemIsDragEnabled;
        if (!index.isValid()) flags |= Qt::ItemIsDropEnabled;
        return flags;
    }

    bool setData(QModelIndex const& index, QVariant const& value, int role = Qt::EditRole) override
    {
        if (index.isValid() && index.row() < rowCount() && Qt::DisplayRole == role)
        {
            list[index.row ()] = value.toString();
            Q_EMIT dataChanged(index, index, QVector<int> {role});
            return true;
        }
        return false;
    }

    Qt::DropActions supportedDropActions() const override {return Qt::MoveAction;}

    bool insertRows(int row, int count, QModelIndex const& parent = QModelIndex {}) override
    {
        beginInsertRows(parent, row, row + count - 1);
        for (int i = 0; i < count; ++i) list.insert(row, {});
        endInsertRows();
        return true;
    }

    bool removeRows(int row, int count, QModelIndex const& parent = QModelIndex {}) override
    {
        beginRemoveRows(parent, row, row + count - 1);
        for (int index = 0; index < count; ++index) list.removeAt(row);
        endRemoveRows();
        return true;
    }

private:
    QStringList list;
};

int main (int argc, char * argv[])
{
    QApplication controller {argc, argv};
    ListModel model;
    QListView view;
    view.setModel (&model);
    view.setDragDropMode (QListView::InternalMove);
    view.show ();
    return controller.exec ();
}