filter tree item by highlight

[d_stranz]

So if you do not want to filter out any items from the tree, then using a QSortFilterProxyModel is probably overkill for this problem. However, if you do use it, then you need to implement the QSortFilterProxyModel::data() method to handle the case where the "role" parameter has the values Qt::ForegroundRole and Qt::BackgroundRole. If the modelIndex is one that should be highlighted, then you should return a QBrush that is your highlight color for the text and background, respectively. If it is not a highlighted item, then you simply return QVariant() and the model/view architecture will display it normally.

If you only have one tree displaying the model (or if you want all views of the model to show the same highlight), then you don't actually need a proxy, you can simply handle this in the model itself.

As you have seen from the examples, QSortFilterProxyModel is generally used for much more complex filtering of a model.

[sajis997]

Thanks for the hint. Lets not over kill it. I already have the sub-classed Model from QAbstractItemModel. And i have over-ridden the data(...) as follows:

QVariant H3DTreeModel::data(const QModelIndex &index, int role) const
{  
    if (!index.isValid())
        return QVariant();
 
    H3DTreeItem *item = static_cast<H3DTreeItem*>(index.internalPointer());
 
    if(role == Qt::DecorationRole)
      {
	return QIcon(":/H3D/images/Node.png");
      }
 
    /*
      display role is used to access string that
      can be displayed as text in the view
     */
    else if(role == Qt::DisplayRole)
      {
	return item->data(index.column());
      }
    else if(role == Qt::UserRole)
      {
	return QPixmap(":/H3D/images/Node.png");
      }
    else if(role == Qt::ToolTipRole)
    {
        //return item->data(index.column());
        if(m_nodeFactory)
        {
            return m_nodeFactory->getNodeData(item->data(index.column()).toString())->nodeData();
        }
        else
            return item->data(index.column());
    }
//    else if(role == Qt::BackgroundRole)
//    {
//        return item->data(index.column());
//    }
//    else if(role == Qt::BackgroundColorRole)
//    {
//        return item->data(index.column());
//    }
//    else if(role == Qt::ForegroundRole)
//    {
//        return item->data(index.column());
//    }
    else 
      return QVariant();
}

QVariant H3DTreeModel::data(const QModelIndex &index, int role) const
{  
    if (!index.isValid())
        return QVariant();

    H3DTreeItem *item = static_cast<H3DTreeItem*>(index.internalPointer());

    if(role == Qt::DecorationRole)
      {
	return QIcon(":/H3D/images/Node.png");
      }

    /*
      display role is used to access string that
      can be displayed as text in the view
     */
    else if(role == Qt::DisplayRole)
      {
	return item->data(index.column());
      }
    else if(role == Qt::UserRole)
      {
	return QPixmap(":/H3D/images/Node.png");
      }
    else if(role == Qt::ToolTipRole)
    {
        //return item->data(index.column());
        if(m_nodeFactory)
        {
            return m_nodeFactory->getNodeData(item->data(index.column()).toString())->nodeData();
        }
        else
            return item->data(index.column());
    }
//    else if(role == Qt::BackgroundRole)
//    {
//        return item->data(index.column());
//    }
//    else if(role == Qt::BackgroundColorRole)
//    {
//        return item->data(index.column());
//    }
//    else if(role == Qt::ForegroundRole)
//    {
//        return item->data(index.column());
//    }
    else 
      return QVariant();
}

To copy to clipboard, switch view to plain text mode 

What other changes i have to do over this model subclasses so that the entered line edit string pattern will match the item in the tree-views and high-light it or expand and high-light it.



Regards
Sajjad

[d_stranz]

I would look at reimplementing the QAbstractItemModel::match() method so that it searches through your tree to return the list of indexes that match the search string. You would then call beginResetModel(), save this list to a member variable in your model class, and trigger a refresh of the view by calling endResetModel().

In the data() method, if the role is Qt::BackgroundRole or Qt::ForegroundRole -and- the index is on the list you saved, you return appropriate brushes for background and foreground highlight (as QVariant), otherwise you return an empty QVariant to show the normal (non-highlighted) appearance.

Note that Qt::BackgroundColorRole is deprecated; you should eliminate this else clause and simply look at the BackgroundRole.

Edit: To expand the highlighted nodes, I think you need to implement a handler for the model's reset() signal in the widget that holds your QTreeView. When you receive it, retrieve the list of matched indexes from the model, then iterate over it, calling the QTreeView::expand() slot for each one.

Further edit, and maybe a simpler way to do this: If the default appearance of selected items is OK for you, then you don't need to implement the BackgroundColor and ForegroundColor role handlers. Instead, pass the results of the match() method to a QItemSelectionModel subclass and set this on the view. The view will then display the selected items with the right colors. This way, you could have the same model displayed in different trees, each one with a different set of nodes highlighted. (Doing it all within the model itself means that every view would be the same).