QTreeView restore Expanded node after reload model

[jpn]

I did it once like this for a static QTreeWidget:

void saveTreeState()
{
    QVariantList states;
    QTreeWidgetItemIterator it(treeWidget);
    while (*it)
    {
        states += (*it)->isExpanded();
        ++it;
    }
    QSettings settings;
    settings.setValue("states", states);
}
 
void restoreTreeState()
{
    QSettings settings;
    QVariantList states = settings.value("states").toList();
    QTreeWidgetItemIterator it(treeWidget);
    while (*it && !states.isEmpty())
    {
        (*it)->setExpanded(states.takeFirst().toBool());
        ++it;
    }
}

void saveTreeState()
{
    QVariantList states;
    QTreeWidgetItemIterator it(treeWidget);
    while (*it)
    {
        states += (*it)->isExpanded();
        ++it;
    }
    QSettings settings;
    settings.setValue("states", states);
}

void restoreTreeState()
{
    QSettings settings;
    QVariantList states = settings.value("states").toList();
    QTreeWidgetItemIterator it(treeWidget);
    while (*it && !states.isEmpty())
    {
        (*it)->setExpanded(states.takeFirst().toBool());
        ++it;
    }
}

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Of course, it doesn't apply in your situation Patrik because you're using a model, not QTreeWidget. But perhaps it turns out to be useful for someone who later searches for a solution on the same subject.