[Interest] Problem understanding QAbstractProxyModel::mapFromSource and displaying summary data from a model

[h]

On Wed, 18 Jul 2012 15:53:54 Tony Rietwyk wrote:
> > Sent: Wednesday, 18 July 2012 2:28 PM
> > 
> > Hi,
> > 
> >  I am writing an app in which I am wanting to display my data in a
> >  number
> 
> of
> 
> > different ways.  (Currently QT4.8 on linux, but will also run it on
> 
> windows, if
> 
> > this is relevant!)
> > 
> > As an example what I have is a set of tuples with two field, say Name
> > and
> > Hours
> > 
> > I have this working with table view and am able to access and edit the
> 
> data.
> 
> > What I want is a not editable view of the data which shows the total of
> 
> all the
> 
> > Hours for each Name.
--snip--
> > With thanks,
> > Hugh
> 
> Hi,
> 
> I think QAbstractProxyModel only applies when there IS a direct mapping
> between the elements of each model, that maintains their identity.
> 
> You need a model with an element for each group (or grouping level), that
> listens for the changes in the source model and adjusts the group's summary,
> then signals the change for that one group.
> 
> The QML VisualDataModel component looks like it has grouping capabilities.
> Maybe you can get some ideas from its implementation?
> 
> Hope that helps,
> 
> Tony.
> 
Hi,
Thanks for the response.  I have not developed great QML skills yet so nothing 
is jumping out at me, but will continue to investigate this.
I am thinking I will  extend my data class to be an aggregation holding 
multiple QAbstractProxyModels and handle the different changes there.

Hugh