c++代码实现qtreewidget支持撤销重做

Qt自带的QUndoStack类可以实现对于QTreeWidget的撤销重做操作，具体实现步骤如下：

1. 定义一个QUndoStack对象

QUndoStack *undoStack;

2. 在QTreeWidget的构造函数中实例化QUndoStack对象

QTreeWidget::QTreeWidget(QWidget *parent): QTreeWidget(parent) {
    undoStack = new QUndoStack(this);
    // other initialization
}

3. 实现插入、删除和修改功能时，将对应的操作封装在QUndoCommand对象中，并将其添加到QUndoStack中

// 插入命令
class InsertCommand : public QUndoCommand {
public:
    InsertCommand(QTreeWidget *tree, QTreeWidgetItem *parent, QTreeWidgetItem *item) :
        tree(tree), parent(parent), item(item) {
        setText("Insert Item");
    }

    void undo() override {
        parent->removeChild(item);
    }

    void redo() override {
        parent->addChild(item);
        tree->setCurrentItem(item);
    }

private:
    QTreeWidget *tree;
    QTreeWidgetItem *parent;
    QTreeWidgetItem *item;
};

void QTreeWidget::insertItem(QTreeWidgetItem *parent, QTreeWidgetItem *item) {
    InsertCommand *command = new InsertCommand(this, parent, item);
    undoStack->push(command);
}

// 删除命令
class RemoveCommand : public QUndoCommand {
public:
    RemoveCommand(QTreeWidget *tree, QTreeWidgetItem *parent, QTreeWidgetItem *item) :
        tree(tree), parent(parent), item(item) {
        setText("Remove Item");
    }

    void undo() override {
        parent->addChild(item);
        tree->setCurrentItem(item);
    }

    void redo() override {
        parent->removeChild(item);
    }

private:
    QTreeWidget *tree;
    QTreeWidgetItem *parent;
    QTreeWidgetItem *item;
};

void QTreeWidget::removeItem(QTreeWidgetItem *parent, QTreeWidgetItem *item) {
    RemoveCommand *command = new RemoveCommand(this, parent, item);
    undoStack->push(command);
}

// 修改命令
class EditCommand : public QUndoCommand {
public:
    EditCommand(QTreeWidgetItem *item, const QString &oldText, const QString &newText) :
        item(item), oldText(oldText), newText(newText) {
        setText("Edit Item");
    }

    void undo() override {
        item->setText(0, oldText);
    }

    void redo() override {
        item->setText(0, newText);
    }

private:
    QTreeWidgetItem *item;
    QString oldText;
    QString newText;
};

void QTreeWidget::editItem(QTreeWidgetItem *item, const QString &oldText, const QString &newText) {
    EditCommand *command = new EditCommand(item, oldText, newText);
    undoStack->push(command);
}

4. 实现撤销和重做功能

void QTreeWidget::undo() {
    undoStack->undo();
}

void QTreeWidget::redo() {
    undoStack->redo();
}

5. 在QTreeWidget的键盘事件中处理撤销和重做快捷键

void QTreeWidget::keyPressEvent(QKeyEvent *event) {
    if (event->matches(QKeySequence::Undo)) {
        undo();
    } else if (event->matches(QKeySequence::Redo)) {
        redo();
    } else {
        QTreeWidget::keyPressEvent(event);
    }
}

以上就是使用QUndoStack实现对于QTreeWidget的撤销重做操作的步骤。