用C++保存QTreeWidget到xml，再读取xml显示为QTreeWidget

以下是一个示例代码，可以将QTreeWidget保存为XML文件，并从XML文件中读取并显示为QTreeWidget：

#include <QtWidgets>
#include <QtXml>

QDomElement widgetToDomXml(QTreeWidgetItem *item, QDomDocument &doc)
{
    QDomElement element = doc.createElement(item->text(0));
    for(int i=0; i<item->childCount(); i++) {
        QTreeWidgetItem *child = item->child(i);
        element.appendChild(widgetToDomXml(child, doc));
    }
    return element;
}

void widgetFromDomXml(QTreeWidgetItem *parent, QDomElement &element)
{
    QTreeWidgetItem *item = new QTreeWidgetItem(parent);
    item->setText(0, element.tagName());
    QDomNodeList children = element.childNodes();
    for(int i=0; i<children.count(); i++) {
        QDomNode childNode = children.item(i);
        if(childNode.isElement()) {
            QDomElement childElement = childNode.toElement();
            widgetFromDomXml(item, childElement);
        }
    }
}

bool saveTreeWidgetToXml(const QTreeWidget *treeWidget, const QString &fileName)
{
    QFile file(fileName);
    if(!file.open(QIODevice::WriteOnly)) {
        return false;
    }
    QDomDocument doc;
    QDomElement root = doc.createElement("TreeWidget");
    doc.appendChild(root);
    for(int i=0; i<treeWidget->topLevelItemCount(); i++) {
        QTreeWidgetItem *item = treeWidget->topLevelItem(i);
        root.appendChild(widgetToDomXml(item, doc));
    }
    QTextStream stream(&file);
    stream << doc.toString();
    file.close();
    return true;
}

bool loadTreeWidgetFromXml(QTreeWidget *treeWidget, const QString &fileName)
{
    QFile file(fileName);
    if(!file.open(QIODevice::ReadOnly)) {
        return false;
    }
    QDomDocument doc;
    if(!doc.setContent(&file)) {
        file.close();
        return false;
    }
    file.close();
    QDomElement root = doc.documentElement();
    for(int i=0; i<root.childNodes().count(); i++) {
        QDomNode childNode = root.childNodes().item(i);
        if(childNode.isElement()) {
            QDomElement childElement = childNode.toElement();
            widgetFromDomXml(treeWidget->invisibleRootItem(), childElement);
        }
    }
    return true;
}

使用示例：

QTreeWidget *treeWidget = new QTreeWidget();
// 添加一些项到treeWidget
//...
// 保存为XML文件
saveTreeWidgetToXml(treeWidget, "tree.xml");
// 清空treeWidget
treeWidget->clear();
// 从XML文件中加载并显示
loadTreeWidgetFromXml(treeWidget, "tree.xml");