Re: Gtk2::SimpleList

[Daniel Kasak <dkasak nusconsulting com au>]

muppet wrote:

> On Sunday, May 30, 2004, at 08:38 PM, Daniel Kasak wrote:
>
> > Right. I'm just getting to the point where I want to use TreeViews 
> > with editable data.
> > How do I know which row has been edited?
> > I can call a sub when a row_changed signal is fired, but the sub only 
> > received 2 things: the simplelist that triggered the signal, and a 
> > Gtk2::Gdk::Event::Button ( whatever that is ).
> > Am I supposed to do something with these to figure out which row has 
> > changed?
>
>
> no, it's a little more involved than that.
>
> the row doesn't get edited; a cell gets edited.  to enable cell 
> editing, you tell the cell renderer to allow editing.  the cell 
> renderer fires a virtual function (not a signal) to start an editing 
> operation, and that's all that the base class does.  CellRendererText 
> creates a new editable and lets the user change the value in the 
> editable, and fires a signal ("edited") when the editing operation is 
> complete (e.g., the editable is destroyed).  this signal gets the path 
> to the edited row, the new text, and the model; you already know which 
> column you're in, because of which cell renderer is being used.
>
> note that this process does *not* automatically apply the new value!  
> SimpleList attaches an "edited" handler to all "text" columns' cell 
> renderers, and that handler applies the new data to the model (see 
> text_cell_edited() in SimpleList.pm).
>
> SimpleList's editable cell support is designed for cases in which you 
> set up the list when you create a dialog, let the user edit it, and 
> then pull all the data out when the user closes the dialog; thus, what 
> you're wanting do to requires more magic^Wdirect usage of the TreeView.
>
> if you want to trigger something after the value has been set, or if 
> you want validate that data and possibly inhibit applying, then you to 
> do fancy stuff with those signals (in which case simplelist may be 
> getting in your way).  if you want to do validation *while* the user 
> edits, you need a custom cell renderer in which you can do your own 
> editing.  (it is rather easy to get SimpleList to use custom 
> renderers, by creating new column types.)
>
>
> Remember -- SimpleList is designed for Simple applications.  You 
> appear to be leaving SimpleLand at full speed.  Are you sure you still 
> want to use SimpleList or just use TreeView and ListStore directly?
Thanks for the explanation.
At least I know what I *can't* do ;)

As for where I'm going from here ...  ummmmmmm ...
I really don't know which I want out of SimpleList, TreeView and ListStore.

What I'm doing is displaying data from a database table, and ( hopefully 
) letting the user update stuff.

It looks like I'll have to leave the SimpleList in place for now, and 
have a separate way of adding / editing data.
I'll have a play around with Gtk2::ListStore and see if I can make it work.

However, one part of muppet's post looks promising for me:

> (it is rather easy to get SimpleList to use custom renderers, by 
> creating new column types.) 

So does that mean I can do all the validation *and* database 
synchronisation in custom cell renderers, and then just drop the 
renderers into a SimpleList?

That sounds like the easiest way to go, as long as I'm not missing 
something.

I will, however, have a look at TreeView / ListStore stuff. Maybe I 
should learn that too?

Dan

--
Daniel Kasak
IT Developer
NUS Consulting Group
Level 5, 77 Pacific Highway
North Sydney, NSW, Australia 2060
T: (+61) 2 9922-7676 / F: (+61) 2 9922 7989
email: dkasak nusconsulting com au
website: http://www.nusconsulting.com.au

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