Re: Adding a customer cell renderer to a simplelist

[muppet <scott asofyet org>]

On Aug 26, 2004, at 9:24 PM, Daniel Kasak wrote:

> So far, I've got:
>
> ---

[create simplelist with 6 columns (2 hidden)]
...
[create new column with custom renderer class and no attribute, and 
append that to the view]

> The column gets added to the simplelist, and the spinbutton renderer 
> appears when I edit the cell, but data that I load into the simplelist 
> doesn't get into the cellrenderer.


you're seeing no data in your added column because you haven't told the 
view column from which model column to retrieve its data.

in cellrenderer_spinbutton.pl, we add the columns with this statement:

  my $column = Gtk2::TreeViewColumn -> new_with_attributes ("no digits",
                                                            $renderer,
                                                            value => 0);

"value" is the name of the CellRendererSpinButton property that 
contains the value that will be displayed.  "0" is the index of the 
model column containing the data we want the view column to display.  
the model column 0 is created with the type Glib::Double.  it's the 
all-important "value => $model_column_index" that is missing from your 
new_with_attributes() call.



> > note that in the cellrenderer_popup.pl example's driver code, the 
> > list data column is created as 'Glib::Scalar', and i used a custom 
> > cell data callback to format the list for display.
>
> Unfortunately I didn't completely understand what this meant at the 
> time, and still don't.
> What does it mean that I have to use a 'scalar' column type when I 
> create the simplelist? Is this referring to the line:
>
> > $column = Gtk2::TreeViewColumn->new_with_attributes(
> >                                                         "Postcode",
> >                                                         $renderer
> >                                                    );

not at all.  you're getting confused between view columns, into which 
you pack cell renderers, and model columns, which have a data type and 
contain data.  view columns display data from one or more (indeed, as 
you have found, possibly zero) model columns.  further blurring the 
distinction between view and model columns, simplelist tries to keep 
them aligned for you; in the simplelist constructor you specify what 
simplelist column type you want, and it creates a model column with a 
corresponding type and a view column with an appropriate renderer.

what that previous message meant was that the data column in the 
*model* needed to have a scalar type.



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