Instantely updateing headerData of QItemModel (QTreeView) when changing selection

[gde23]

Hello,
i have a QTreeView with differnt sorts of members in each row and therefore want to change the desctiption in the header according to the current selection.

What i have come up with is following:

QVariant TreeModel::headerData(int section, Qt::Orientation orientation, int role) const {
    if (orientation == Qt::Horizontal && role == Qt::DisplayRole) {
        QModelIndex index = m_tree_view->currentIndex();
        TreeItem* Item_selected = static_cast<TreeItem*>(index.internalPointer());
        std::string value;
        if(Item_selected != 0) {
            value = Item_selected->getDispName(section);
        } else{
            value = m_root_item->getDispName(section);
        }
        return QVariant(value.c_str());
    }
    return QVariant();
}

This works fine, however it often tankes some time till the headers get updated, (mouseover helps, but sometimes works without)
Is there a way to re-draw the header instantainiously?

[iota142]

Hi,

Do you emit the signal QAbstractItemModel::headerDataChanged() when you change your header datas?

The documentation says: "When reimplementing the setHeaderData() function, this signal must be emitted explicitly."
-> documentation of QAbstractItemModel::headerDataChanged.

[VRonin]

https://en.wikipedia.org/wiki/Dependency_inversion_principle

Basically what you are doing is evil.

You should connect m_tree_view->selectionModel()'s currentIndexChanged() signal with a slot that calls setHeaderData in the model. that's all