c++ qtreewidget支持撤销恢复功能

QTreeWidget本身并不直接支持撤销/恢复功能，但可以利用QUndoStack来实现。下面是一个简单的示例代码，用来演示如何实现QTreeWidget的撤销/恢复功能：

#include <QtWidgets>

struct TreeOperation {
    enum Type { Insert, Remove, Move, Update };
    Type type;
    QTreeWidgetItem *item;
    QTreeWidgetItem *parent;
    int index;
    QVariantList data;
};

class TreeOperationCommand : public QUndoCommand {
public:
    TreeOperationCommand(QTreeWidget *tree, const TreeOperation &op) :
        QUndoCommand(),
        m_tree(tree),
        m_op(op)
    {
        setText(operationToString(m_op.type));
    }

    void undo() override
    {
        switch (m_op.type) {
        case TreeOperation::Insert:
            m_tree->blockSignals(true);
            m_op.parent->removeChild(m_op.item);
            m_tree->blockSignals(false);
            break;
        case TreeOperation::Remove:
            m_tree->blockSignals(true);
            m_op.parent->insertChild(m_op.index, m_op.item);
            m_tree->blockSignals(false);
            break;
        case TreeOperation::Move:
            m_tree->blockSignals(true);
            m_op.parent->takeChild(m_op.index);
            m_op.parent->insertChild(m_op.item);
            m_tree->blockSignals(false);
            break;
        case TreeOperation::Update:
            m_tree->blockSignals(true);
            for (int i = 0; i < m_op.data.count(); i++) {
                m_op.item->setData(i, Qt::EditRole, m_op.data[i]);
            }
            m_tree->blockSignals(false);
            break;
        }
    }

    void redo() override
    {
        switch (m_op.type) {
        case TreeOperation::Insert:
            m_tree->blockSignals(true);
            m_op.parent->insertChild(m_op.index, m_op.item);
            m_tree->blockSignals(false);
            break;
        case TreeOperation::Remove:
            m_tree->blockSignals(true);
            m_op.parent->removeChild(m_op.item);
            m_tree->blockSignals(false);
            break;
        case TreeOperation::Move:
            m_tree->blockSignals(true);
            m_op.parent->takeChild(m_op.index);
            m_op.parent->insertChild(m_op.item);
            m_tree->blockSignals(false);
            break;
        case TreeOperation::Update:
            m_tree->blockSignals(true);
            for (int i = 0; i < m_op.data.count(); i++) {
                m_op.item->setData(i, Qt::EditRole, m_op.data[i]);
            }
            m_tree->blockSignals(false);
            break;
        }
    }

private:
    QTreeWidget *m_tree;
    TreeOperation m_op;

    QString operationToString(TreeOperation::Type type) const
    {
        switch (type) {
        case TreeOperation::Insert:
            return "Insert";
        case TreeOperation::Remove:
            return "Remove";
        case TreeOperation::Move:
            return "Move";
        case TreeOperation::Update:
            return "Update";
        }
        return "";
    }
};

class TreeWidget : public QTreeWidget {
public:
    TreeWidget(QWidget *parent = nullptr) : QTreeWidget(parent)
    {
        m_undoStack = new QUndoStack(this);
        connect(this, &QTreeWidget::itemChanged, this, &TreeWidget::onItemChanged);
    }

    void insertItem(QTreeWidgetItem *parent, int index, QTreeWidgetItem *item)
    {
        TreeOperation op;
        op.type = TreeOperation::Insert;
        op.item = item;
        op.parent = parent;
        op.index = index;
        op.data = itemData(item);
        m_undoStack->push(new TreeOperationCommand(this, op));
    }

    void removeItem(QTreeWidgetItem *parent, int index, QTreeWidgetItem *item)
    {
        TreeOperation op;
        op.type = TreeOperation::Remove;
        op.item = item;
        op.parent = parent;
        op.index = index;
        op.data = itemData(item);
        m_undoStack->push(new TreeOperationCommand(this, op));
    }

    void moveItem(QTreeWidgetItem *parent, int oldIndex, int newIndex, QTreeWidgetItem *item)
    {
        TreeOperation op;
        op.type = TreeOperation::Move;
        op.item = item;
        op.parent = parent;
        op.index = oldIndex;
        op.data = itemData(item);
        m_undoStack->push(new TreeOperationCommand(this, op));
    }

    void updateItem(QTreeWidgetItem *item)
    {
        TreeOperation op;
        op.type = TreeOperation::Update;
        op.item = item;
        op.parent = item->parent();
        op.index = indexOfTopLevelItem(item);
        op.data = itemData(item);
        m_undoStack->push(new TreeOperationCommand(this, op));
    }

    void undo()
    {
        m_undoStack->undo();
    }

    void redo()
    {
        m_undoStack->redo();
    }

private:
    QUndoStack *m_undoStack;

    QVariantList itemData(QTreeWidgetItem *item) const
    {
        QVariantList data;
        int count = item->columnCount();
        for (int i = 0; i < count; i++) {
            data.append(item->data(i, Qt::EditRole));
        }
        return data;
    }

    void onItemChanged(QTreeWidgetItem *item, int column)
    {
        updateItem(item);
    }
};

在上面的示例代码中，我们定义了一个TreeOperation结构体，用来记录树形结构的操作，包括插入、删除、移动和更新等操作。然后，我们定义了一个TreeOperationCommand类，用来封装每个操作，并将其添加到QUndoStack中。在TreeWidget类中，我们重载了insertItem、removeItem、moveItem和updateItem方法，用来记录每个操作，并将其封装成TreeOperationCommand对象，并将其添加到QUndoStack中。最后，我们定义了undo和redo方法，用来执行撤销和恢复操作。