When and where to invoke QAbstractItemView::setIndexWidge?

[mallun.wang]

Hi all experts,
First apologize for my poor English.
I have searched related threads but still have no solution.

My goal is to display a customed widget in QTreeView's last column.
I have two solultions to achieve that:
1. use QItemDelegate::createEditor, setEditorData, setModelData, updateEditorGeometry...
2. use QAbstractItemView::setIndexWidge

Because the UI spec requires that the customed widget should always get displayed, no matter it is in edit status, I prefer the solution 2 - use QAbstractItemView::setIndexWidge.

Now my question is when and where to invoke QAbstractItemView::setIndexWidge.


My tree is QTreeView+QAbstractItemModel structure. I subclasses QTreeView andQAbstractItemModel, and I initialize my model's data from a ABClist.

code:

QModelIndex TreeModel::index(int row, int column, const QModelIndex &parent)
            const
{
    if (!hasIndex(row, column, parent))
        return QModelIndex();
 
    TreeItem *parentItem;
 
    if (!parent.isValid())
        parentItem = rootItem;
    else
        parentItem = static_cast<TreeItem*>(parent.internalPointer());
 
    TreeItem *childItem = parentItem->child(row);
    if (childItem)
    {
        QModelIndex index;
        index=createIndex(row, column, childItem);
 
        return index;
    }
    else
        return QModelIndex();
}
 
QModelIndex TreeModel::parent(const QModelIndex &index) const
{
    if (!index.isValid())
        return QModelIndex();
 
    TreeItem *childItem = static_cast<TreeItem*>(index.internalPointer());
    TreeItem *parentItem = childItem->parent();
 
    if (parentItem == rootItem)
        return QModelIndex();
 
    return createIndex(parentItem->row(), 0, parentItem);
}
 
QVariant TreeModel::data(const QModelIndex &index, int role) const
{
    if (!index.isValid())
        return QVariant();
 
    if (role != Qt::DisplayRole)
        return QVariant();
 
    TreeItem *item = static_cast<TreeItem*>(index.internalPointer());
 
    return item->data(index.column());
}

QModelIndex TreeModel::index(int row, int column, const QModelIndex &parent)
            const
{
    if (!hasIndex(row, column, parent))
        return QModelIndex();

    TreeItem *parentItem;

    if (!parent.isValid())
        parentItem = rootItem;
    else
        parentItem = static_cast<TreeItem*>(parent.internalPointer());

    TreeItem *childItem = parentItem->child(row);
    if (childItem)
    {
        QModelIndex index;
        index=createIndex(row, column, childItem);

        return index;
    }
    else
        return QModelIndex();
}

QModelIndex TreeModel::parent(const QModelIndex &index) const
{
    if (!index.isValid())
        return QModelIndex();

    TreeItem *childItem = static_cast<TreeItem*>(index.internalPointer());
    TreeItem *parentItem = childItem->parent();

    if (parentItem == rootItem)
        return QModelIndex();

    return createIndex(parentItem->row(), 0, parentItem);
}

QVariant TreeModel::data(const QModelIndex &index, int role) const
{
    if (!index.isValid())
        return QVariant();

    if (role != Qt::DisplayRole)
        return QVariant();

    TreeItem *item = static_cast<TreeItem*>(index.internalPointer());

    return item->data(index.column());
}

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The approach to add data into my model is to add/modify the ABClist and then invoke QAbstractItemModel::reset.

Now it looks perfect to add data but I don't know where and when to invoke QAbstractItemView::setIndexWidge to set my customed widget. Because I only add/modify data in my model class, but setIndexWidge is in QAbstractItemView class.

I tried to rewrite QAbstractItemView::dataChanged and QAbstractItemView::rowsInserted, in these two virtual functions, I want to invoke QAbstractItemView::setIndexWidge to set my customed widget, but these two virtual functions never invoked when I modify ABClist or invoke QAbstractItemModel::reset. Why???

Any idea when and where to invoke QAbstractItemView::setIndexWidge?
Thanks in advance.

[wysota]

You may invoke the method whenever you want after a particular row/column in the model has been created. Just remember the widget will have nothing in common with your model - it will just be a widget placed in another widget that you will have to control (and synchronize with the model) all by yourself.