[Qt-interest] ModelView - how to use proxies to filter this data?

[Stephen Kelly]

Daniel Price wrote:

> I've been playing with this sortfilter approach and it works fine if the
> layout of the source matches the output. However, what if my source items
> are buried away?
> 
> Eg:
> 
> --Companies
> ----Company1
> ------Product1
> ------Product2
> ------Product3
> ----Company2
> ------Product4
> 
> The above is stored within a QAbstractItemModel and I want to use a proxy
> to just pull out all the products to give me this in a table:
> 
> --Product1
> --Product2
> --Product3
> --Product4
> 
> How could I do this using a proxy? If I store a unique identifier in each
> of the product rows identifying it as a Product record, could I somehow
> use the built-in filtering to get just those rows?


You could do this using a proxy. The way I've done it is to flatten the tree 
into a list, then filter out Company* from the list.

Some screenshots here: 

http://api.kde.org/playground-api/pim-
apidocs/akonadi/akonadi_next/html/index.html

(Look for DescendantEntitiesProxyModel)

All the best,

Steve.

> 
> 
>> -----Original Message-----
>> From: qt-interest-bounces at trolltech.com [mailto:qt-interest-
>> bounces at trolltech.com] On Behalf Of Sean Harmer
>> Sent: 01 December 2009 15:54
>> To: qt-interest at trolltech.com
>> Subject: Re: [Qt-interest] ModelView - how to use proxies to filter
>> this data?
>>
>> Hi,
>>
>> On Tuesday 01 December 2009 15:36:18 Daniel Price wrote:
>> > Thanks for the info. I hadn't considered using a proxy filter and
>> just
>> >  accepting/rejecting rows. Does that work with hierarchical data
>> though?
>>
>> Yes it works absolutely fine with hierarchical data as that is what I
>> am using.
>>
>> > I actually QAbstractProxyModel and implemented the mapTo/mapFrom
>> functions.
>> >  But sorting doesn't seem to work.
>>
>> Yeah I thought about doing it that way, but then decided that
>> QSortFilterProxyModel fitted my needs with a little subclassing.
>>
>> > BTW it looks like you're storing pointers to your structures in your
>> >  variants as integers and casting them back.
>>
>> No I am storing them as void* in the QModelIndex's internal pointer so
>> that is
>> why I am casting them back to my specific types. My model's index
>> function
>> looks like this:
>>
>> QModelIndex MapsData1DTreeModel::index( int row, int col, const
>> QModelIndex&
>> parent ) const
>> {
>>     MapsData1DTreeModelGroupNode* parentItem;
>>     if ( !parent.isValid() )
>>         parentItem = m_root;
>>     else
>>         parentItem = static_cast<MapsData1DTreeModelGroupNode*>(
>> parent.internalPointer() );
>>
>>     MapsData1DTreeModelNode* childItem = parentItem->child( row );
>>     if ( childItem )
>>         return createIndex( row, col, childItem );
>>     else
>>         return QModelIndex();
>> }
>>
>> Good luck.
>>
>> Sean
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