Using a custom data type and editor in QStandardItemModel

Christian Ehrlicher

How do you set the data? Please show some code.

Lurkki

@Christian-Ehrlicher
Setting the data initially:

    std::function<void(tc_assignable_node_t*, QStandardItem*)> traverse;
    traverse = [=, &traverse](tc_assignable_node_t *node, QStandardItem *item) {
        if (node == NULL) {
            return;
        }
        
        if (node->name != NULL) { 
            qDebug() << node->name;
        }
        
        // List for adding the name and editor on the same row
        QList <QStandardItem*> rowItems;
        
        QStandardItem *nameItem = new QStandardItem;
        nameItem->setText(node->name);
        nameItem->setEditable(false);
        rowItems.append(nameItem);
        
        // Don't add editor item for TC_ASSIGNABLE_NONE nodes
        if (node->value_category != TC_ASSIGNABLE_NONE) {
            QStandardItem *editorItem = new QStandardItem;
            QVariant v;
            AssignableData data(node);
            v.setValue(data);
            editorItem->setData(v, Qt::EditRole);
            //editorItem->setText(node->name);
            rowItems.append(editorItem);
        }
        
        item->appendRow(rowItems);
        
        for (uint32_t i = 0; i < node->children_count; i++) {
            traverse(node->children_nodes[i], nameItem);
        }
    };

setModelData() of my delegate:

    AssignableData data = qvariant_cast<AssignableData>(index.model()->data(index));
    QVariant v;
    QStandardItemModel *s_model = static_cast<QStandardItemModel*>(model);
...
IntRangeEditor *ed = static_cast<IntRangeEditor*>(editor);
                    data.setValue(ed->value());
                    v.setValue(data);
                    s_model->setData(index, v, Qt::EditRole);
                    //s_model->itemFromIndex(index)->setText("");

without the last line uncommented, it seems to overwrite the item's entire data and it becomes ineditable

Christian Ehrlicher

@Lurkki said in Using a custom data type and editor in QStandardItemModel:

without the last line uncommented,

You mean '//s_model->itemFromIndex(index)->setText("");' ?
This will set the Qt::DisplayRole and Qt::EditRole as explained in the documentation

Lurkki

@Christian-Ehrlicher s_model->setData(index,"a", Qt::DisplayRole); has the same effect, it overwrites my custom data

mrjj

Hi
I might have missed something but i only see you using
Qt::EditRole
so where is this custom data stored and in what way
"becomes ineditable" its still shown but you can type in it or ?

Lurkki

@mrjj My mistake, yeah I can edit it but my custom data disappears. The data is stored in the model.

Christian Ehrlicher

@Lurkki said in Using a custom data type and editor in QStandardItemModel:

has the same effect, it overwrites my custom data

I would say it's a bug if it's not - see the documentation...

Note: The default implementation treats Qt::EditRole and Qt::DisplayRole as referring to the same data.

Lurkki

@Christian-Ehrlicher How should I go about subclassing QStandardItem and reimplementing setData then? I can't seem to find much information about it.

mrjj

@Lurkki

Hi
Can you please make a small example showing this ?,

I have a bad feeling its just incorrect use / expectations and
not an actual bug.

Qt::EditRole and Qt::DisplayRole is the same so that is expected.

try to use Qt::UserRole for your custom data end see.

To use custom data, you can use

setData(index,"a", Qt::UserRole );
setData(index,"a", Qt::UserRole +1);
setData(index,"a", Qt::UserRole +2);

Lurkki

@mrjj Thanks, that works for my use case

Setting the data:

        if (node->value_category != TC_ASSIGNABLE_NONE) {
            QStandardItem *editorItem = new QStandardItem;
            QVariant v;
            AssignableData data(node);
            v.setValue(data);
            editorItem->setData(v, Qt::UserRole);
            //editorItem->setText(node->name);
            rowItems.append(editorItem);
        }

Setting editor data in the delegate:

void AssignableEditorDelegate::setEditorData(QWidget* editor, const QModelIndex &index) const {
    AssignableData data = qvariant_cast<AssignableData>(index.model()->data(index, Qt::UserRole));
    
    switch (data.m_valueCategory) {
        case TC_ASSIGNABLE_RANGE:
            switch (data.m_rangeInfo.range_data_type) {
                case TC_ASSIGNABLE_RANGE_INT: {
                    IntRangeEditor *ed = static_cast<IntRangeEditor*>(editor);
                    ed->setValue(data.value().toInt());
                    break;
                }
                default:
                    break;
            }
        default:
            break;
    }
}

Setting model data:

void AssignableEditorDelegate::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const {
    AssignableData data = qvariant_cast<AssignableData>(index.model()->data(index, Qt::UserRole));
    QVariant v;
    QStandardItemModel *s_model = static_cast<QStandardItemModel*>(model);
    
    switch (data.m_valueCategory) {
        ...
        case TC_ASSIGNABLE_RANGE:
            switch (data.m_rangeInfo.range_data_type) {
                case TC_ASSIGNABLE_RANGE_INT: {
                    IntRangeEditor *ed = static_cast<IntRangeEditor*>(editor);
                    data.setValue(ed->value());
                    v.setValue(data);
                    s_model->setData(index, v, Qt::UserRole);
                    s_model->setData(index, ed->value(), Qt::DisplayRole);
                    break;
                    }
                default:
                    break;
            }
        default:
            break;
    }
}

I also had to do setAutoFillBackground(true); in my editor widget to make the display text not overlap with the editor.