編集可能なツリーモデルの例

class TreeItem
{
public:
    explicit TreeItem(QVariantList data, TreeItem *parent = nullptr);

    TreeItem *child(int number);
    int childCount() const;
    int columnCount() const;
    QVariant data(int column) const;
    bool insertChildren(int position, int count, int columns);
    bool insertColumns(int position, int columns);
    TreeItem *parent();
    bool removeChildren(int position, int count);
    bool removeColumns(int position, int columns);
    int row() const;
    bool setData(int column, const QVariant &value);

private:
    std::vector<std::unique_ptr<TreeItem>> m_childItems;
    QVariantList itemData;
    TreeItem *m_parentItem;
};

TreeItem::TreeItem(QVariantList data, TreeItem *parent)
    : itemData(std::move(data)), m_parentItem(parent)
{}

TreeItem *TreeItem::parent()
{
    return m_parentItem;
}

TreeItem *TreeItem::child(int number)
{
    return (number >= 0 && number < childCount())
        ? m_childItems.at(number).get() : nullptr;
}

int TreeItem::childCount() const
{
    return int(m_childItems.size());
}

int TreeItem::row() const
{
    if (!m_parentItem)
        return 0;
    const auto it = std::find_if(m_parentItem->m_childItems.cbegin(), m_parentItem->m_childItems.cend(),
                                 [this](const std::unique_ptr<TreeItem> &treeItem) {
        return treeItem.get() == this;
    });

    if (it != m_parentItem->m_childItems.cend())
        return std::distance(m_parentItem->m_childItems.cbegin(), it);
    Q_ASSERT(false); // should not happen
    return -1;
}

int TreeItem::columnCount() const
{
    return int(itemData.count());
}

QVariant TreeItem::data(int column) const
{
    return itemData.value(column);
}

bool TreeItem::setData(int column, const QVariant &value)
{
    if (column < 0 || column >= itemData.size())
        return false;

    itemData[column] = value;
    return true;
}

bool TreeItem::insertChildren(int position, int count, int columns)
{
    if (position < 0 || position > qsizetype(m_childItems.size()))
        return false;

    for (int row = 0; row < count; ++row) {
        QVariantList data(columns);
        m_childItems.insert(m_childItems.cbegin() + position,
                std::make_unique<TreeItem>(data, this));
    }

    return true;
}

bool TreeItem::removeChildren(int position, int count)
{
    if (position < 0 || position + count > qsizetype(m_childItems.size()))
        return false;

    for (int row = 0; row < count; ++row)
        m_childItems.erase(m_childItems.cbegin() + position);

    return true;
}

bool TreeItem::insertColumns(int position, int columns)
{
    if (position < 0 || position > itemData.size())
        return false;

    for (int column = 0; column < columns; ++column)
        itemData.insert(position, QVariant());

    for (auto &child : std::as_const(m_childItems))
        child->insertColumns(position, columns);

    return true;
}

class TreeModel : public QAbstractItemModel
{
    Q_OBJECT

public:
    Q_DISABLE_COPY_MOVE(TreeModel)

    TreeModel(const QStringList &headers, const QString &data,
              QObject *parent = nullptr);
    ~TreeModel() override;

    QVariant data(const QModelIndex &index, int role) const override;
    QVariant headerData(int section, Qt::Orientation orientation,
                        int role = Qt::DisplayRole) const override;

    QModelIndex index(int row, int column,
                      const QModelIndex &parent = {}) const override;
    QModelIndex parent(const QModelIndex &index) const override;

    int rowCount(const QModelIndex &parent = {}) const override;
    int columnCount(const QModelIndex &parent = {}) const override;

    Qt::ItemFlags flags(const QModelIndex &index) const override;
    bool setData(const QModelIndex &index, const QVariant &value,
                 int role = Qt::EditRole) override;
    bool setHeaderData(int section, Qt::Orientation orientation,
                       const QVariant &value, int role = Qt::EditRole) override;

    bool insertColumns(int position, int columns,
                       const QModelIndex &parent = {}) override;
    bool removeColumns(int position, int columns,
                       const QModelIndex &parent = {}) override;
    bool insertRows(int position, int rows,
                    const QModelIndex &parent = {}) override;
    bool removeRows(int position, int rows,
                    const QModelIndex &parent = {}) override;

private:
    void setupModelData(const QList<QStringView> &lines);
    TreeItem *getItem(const QModelIndex &index) const;

    std::unique_ptr<TreeItem> rootItem;
};

TreeModel::TreeModel(const QStringList &headers, const QString &data, QObject *parent)
    : QAbstractItemModel(parent)
{
    QVariantList rootData;
    for (const QString &header : headers)
        rootData << header;

    rootItem = std::make_unique<TreeItem>(rootData);
    setupModelData(QStringView{data}.split(u'\n'));
}

TreeModel::~TreeModel() = default;

TreeItem *TreeModel::getItem(const QModelIndex &index) const
{
    if (index.isValid()) {
        if (auto *item = static_cast<TreeItem*>(index.internalPointer()))
            return item;
    }
    return rootItem.get();
}

int TreeModel::rowCount(const QModelIndex &parent) const
{
    if (parent.isValid() && parent.column() > 0)
        return 0;

    const TreeItem *parentItem = getItem(parent);

    return parentItem ? parentItem->childCount() : 0;
}

int TreeModel::columnCount(const QModelIndex &parent) const
{
    Q_UNUSED(parent);
    return rootItem->columnCount();
}

Qt::ItemFlags TreeModel::flags(const QModelIndex &index) const
{
    if (!index.isValid())
        return Qt::NoItemFlags;

    return Qt::ItemIsEditable | QAbstractItemModel::flags(index);
}

QModelIndex TreeModel::index(int row, int column, const QModelIndex &parent) const
{
    if (parent.isValid() && parent.column() != 0)
        return {};

    TreeItem *parentItem = getItem(parent);
    if (!parentItem)
        return {};

    if (auto *childItem = parentItem->child(row))
        return createIndex(row, column, childItem);
    return {};
}

QModelIndex TreeModel::parent(const QModelIndex &index) const
{
    if (!index.isValid())
        return {};

    TreeItem *childItem = getItem(index);
    TreeItem *parentItem = childItem ? childItem->parent() : nullptr;

    return (parentItem != rootItem.get() && parentItem != nullptr)
        ? createIndex(parentItem->row(), 0, parentItem) : QModelIndex{};
}

class TestEditableTreeModel : public QObject
{
    Q_OBJECT

private slots:
    void testTreeModel();
};

void TestEditableTreeModel::testTreeModel()
{
    constexpr auto fileName = ":/default.txt"_L1;
    QFile file(fileName);
    QVERIFY2(file.open(QIODevice::ReadOnly | QIODevice::Text),
             qPrintable(fileName + " cannot be opened: "_L1 + file.errorString()));

    const QStringList headers{"column1"_L1, "column2"_L1};
    TreeModel model(headers, QString::fromUtf8(file.readAll()));

    QAbstractItemModelTester tester(&model);
}

QTEST_APPLESS_MAIN(TestEditableTreeModel)

#include "test.moc"

# Unit Test

include(CTest)

qt_add_executable(editabletreemodel_tester
    test.cpp
    treeitem.cpp treeitem.h
    treemodel.cpp treemodel.h)

target_link_libraries(editabletreemodel_tester PRIVATE
    Qt6::Core
    Qt6::Test
)

if(ANDROID)
    target_link_libraries(editabletreemodel_tester PRIVATE
        Qt6::Gui
    )
endif()

qt_add_resources(editabletreemodel_tester "editabletreemodel_tester"
    PREFIX
        "/"
    FILES
        ${editabletreemodel_resource_files}
)

add_test(NAME editabletreemodel_tester
         COMMAND editabletreemodel_tester)