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

实现方法：

1.将QTreeWidget的数据保存到xml文件中。

2.从xml文件中读取数据并显示在QTreeWidget中。

下面是示例代码：

保存QTreeWidget多列数据到xml：

void 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("tree");

    for (int i = 0; i < treeWidget->topLevelItemCount(); i++) {
        QTreeWidgetItem *item = treeWidget->topLevelItem(i);
        writer.writeStartElement("item");
        for (int j = 0; j < item->columnCount(); j++) {
            writer.writeStartElement("column");
            writer.writeAttribute("index", QString::number(j));
            writer.writeCharacters(item->text(j));
            writer.writeEndElement();
        }
        writer.writeEndElement();
    }

    writer.writeEndElement();
    writer.writeEndDocument();

    file.close();
}

从xml文件中读取数据并显示在QTreeWidget中：

void 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() == "item") {
            QTreeWidgetItem *item = new QTreeWidgetItem();
            while (!reader.atEnd()) {
                reader.readNext();
                if (reader.isStartElement() && reader.name() == "column") {
                    int index = reader.attributes().value("index").toInt();
                    item->setText(index, reader.readElementText());
                }
                if (reader.isEndElement() && reader.name() == "item") {
                    treeWidget->addTopLevelItem(item);
                    break;
                }
            }
        }
    }

    file.close();
}