c++ qtreewidget支持撤销与恢复功能 代码

Qt的QTreeWidget没有自带的撤销与恢复功能，但是我们可以结合QUndoStack来实现。

以下是一个简单的示例代码：

#include <QtWidgets>

class TreeWidget : public QTreeWidget
{
    Q_OBJECT

public:
    TreeWidget(QWidget *parent = nullptr);

public slots:
    void addItem();
    void removeItem();
    void undo();
    void redo();

private:
    QUndoStack *m_undoStack;
};

TreeWidget::TreeWidget(QWidget *parent)
    : QTreeWidget(parent)
{
    // 创建撤销栈
    m_undoStack = new QUndoStack(this);

    // 添加菜单项
    QAction *addItemAction = new QAction(tr("&Add Item"), this);
    connect(addItemAction, &QAction::triggered, this, &TreeWidget::addItem);
    addAction(addItemAction);

    QAction *removeItemAction = new QAction(tr("&Remove Item"), this);
    connect(removeItemAction, &QAction::triggered, this, &TreeWidget::removeItem);
    addAction(removeItemAction);

    // 添加撤销和恢复菜单项
    QAction *undoAction = m_undoStack->createUndoAction(this, tr("&Undo"));
    undoAction->setShortcuts(QKeySequence::Undo);
    QAction *redoAction = m_undoStack->createRedoAction(this, tr("&Redo"));
    redoAction->setShortcuts(QKeySequence::Redo);
    addAction(undoAction);
    addAction(redoAction);
}

void TreeWidget::addItem()
{
    QTreeWidgetItem *item = new QTreeWidgetItem(QStringList() << tr("Item"));
    m_undoStack->push(new QTreeWidgetItemRemovedCommand(this, item));
}

void TreeWidget::removeItem()
{
    QTreeWidgetItem *item = currentItem();
    if (item) {
        m_undoStack->push(new QTreeWidgetItemAddedCommand(this, item));
        delete item;
    }
}

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

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

// 定义命令类
class QTreeWidgetItemAddedCommand : public QUndoCommand
{
public:
    QTreeWidgetItemAddedCommand(QTreeWidget *treeWidget, QTreeWidgetItem *item)
        : m_treeWidget(treeWidget), m_item(item)
    {
        setText(tr("Add Item"));
    }

    void undo() override
    {
        m_treeWidget->removeItemWidget(m_item);
    }

    void redo() override
    {
        m_treeWidget->addTopLevelItem(m_item);
    }

private:
    QTreeWidget *m_treeWidget;
    QTreeWidgetItem *m_item;
};

class QTreeWidgetItemRemovedCommand : public QUndoCommand
{
public:
    QTreeWidgetItemRemovedCommand(QTreeWidget *treeWidget, QTreeWidgetItem *item)
        : m_treeWidget(treeWidget), m_item(item)
    {
        setText(tr("Remove Item"));
    }

    void undo() override
    {
        m_treeWidget->addTopLevelItem(m_item);
    }

    void redo() override
    {
        m_treeWidget->removeItemWidget(m_item);
    }

private:
    QTreeWidget *m_treeWidget;
    QTreeWidgetItem *m_item;
};

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    TreeWidget treeWidget;
    treeWidget.show();

    return app.exec();
}

#include "main.moc"

在这个示例代码中，我们创建了一个TreeWidget类继承自QTreeWidget，并在其中添加了撤销和恢复功能。我们使用QUndoStack来管理所有的撤销和恢复操作，并在addItem和removeItem槽函数中创建并添加相应的命令类。

每次执行addItem或removeItem时，我们都会在撤销栈中添加对应的命令类，并在undo和redo槽函数中执行相应的撤销和恢复操作。

注意，在添加或删除QTreeWidgetItem时，我们需要使用QTreeWidget的addItem和removeItemWidget函数，而不是QTreeWidgetItem的addChild和removeChild函数。这是因为QTreeWidgetItem的addChild和removeChild函数并不会将它从它的父项中移除，而只是从它的父项的子项列表中移除。这可能会导致撤销和恢复操作出现问题。