用C++保存QTreeWidget多列数据到xml，再读取xml显示为QTreeWidget

以下是一个示例代码，展示如何使用Qt的QXmlStreamWriter和QXmlStreamReader将QTreeWidget的多个列数据保存到XML文件中，并从XML文件中读取并显示在QTreeWidget中。

保存QTreeWidget到XML：

void MainWindow::saveToXml(QTreeWidget *treeWidget, const QString &filename)
{
    QFile file(filename);
    if (!file.open(QIODevice::WriteOnly | QIODevice::Text))
        return;

    QXmlStreamWriter writer(&file);
    writer.setAutoFormatting(true);
    writer.writeStartDocument();

    writer.writeStartElement("TreeWidget");

    for (int i = 0; i < treeWidget->topLevelItemCount(); ++i) {
        QTreeWidgetItem *item = treeWidget->topLevelItem(i);
        saveItem(writer, item);
    }

    writer.writeEndElement();

    writer.writeEndDocument();
    file.close();
}

void MainWindow::saveItem(QXmlStreamWriter &writer, QTreeWidgetItem *item)
{
    writer.writeStartElement("Item");

    writer.writeAttribute("text", item->text(0));

    for (int i = 1; i < item->columnCount(); ++i) {
        writer.writeStartElement("Column");
        writer.writeAttribute("index", QString::number(i));
        writer.writeCharacters(item->text(i));
        writer.writeEndElement();
    }

    for (int i = 0; i < item->childCount(); ++i) {
        QTreeWidgetItem *child = item->child(i);
        saveItem(writer, child);
    }

    writer.writeEndElement();
}

从XML加载QTreeWidget：

void MainWindow::loadFromXml(QTreeWidget *treeWidget, const QString &filename)
{
    QFile file(filename);
    if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
        return;

    QXmlStreamReader reader(&file);

    while (!reader.atEnd()) {
        reader.readNext();
        if (reader.isStartElement() && reader.name() == "TreeWidget") {
            loadTreeWidget(reader, treeWidget);
        }
    }

    file.close();
}

void MainWindow::loadTreeWidget(QXmlStreamReader &reader, QTreeWidget *treeWidget)
{
    while (!reader.atEnd()) {
        reader.readNext();
        if (reader.isEndElement() && reader.name() == "TreeWidget") {
            break;
        }
        if (reader.isStartElement() && reader.name() == "Item") {
            loadItem(reader, treeWidget);
        }
    }
}

void MainWindow::loadItem(QXmlStreamReader &reader, QTreeWidgetItem *parent)
{
    QString text;
    QList<QString> columns;

    if (reader.attributes().hasAttribute("text")) {
        text = reader.attributes().value("text").toString();
    }

    while (!reader.atEnd()) {
        reader.readNext();
        if (reader.isEndElement() && reader.name() == "Item") {
            break;
        }
        if (reader.isStartElement() && reader.name() == "Column") {
            int index = reader.attributes().value("index").toInt();
            QString column = reader.readElementText();
            while (columns.size() < index) {
                columns.append("");
            }
            columns[index - 1] = column;
        }
    }

    QTreeWidgetItem *item = new QTreeWidgetItem(parent, QStringList(text));
    for (int i = 0; i < columns.size(); ++i) {
        item->setTextAlignment(i + 1, Qt::AlignCenter);
        item->setText(i + 1, columns[i]);
    }

    while (!reader.atEnd()) {
        reader.readNext();
        if (reader.isEndElement() && reader.name() == "Item") {
            break;
        }
        if (reader.isStartElement() && reader.name() == "Item") {
            loadItem(reader, item);
        }
    }
}