Re: Editable GtkCellRendererText and focus

["Matthias Clasen" <matthias clasen gmail com>]

On 6/12/07, Kristian Rietveld <kris gtk org> wrote:
> On Mon, Jun 11, 2007 at 05:27:05PM +1200, Tim Evans wrote:
> > I've attached a small PyGTK script that illustrates the problem.  Our
> > users are presented with a GtkTreeView containing a list of strings to
> > edit.  Having changed the values to their satisfaction, they click "OK".
> > The problem is that the last change they make is not applied: no
> > 'edited' signal is emitted on the GtkCellRendererText, so my code does
> > not modify the underlying model.
>
> This is not a really easy problem :)  I think we have to take two things
> into account when contemplating about this:
>
>   1. What to do when the tree view loses focus?  Do we leave the cell in
>      editing mode, or do we stop editing.
>
>      Years ago, I think in 2.2 already, we have made changes to stop
>      editing as soon as focus was lost.  I think this has been working
>      well over the last few years.
>
>   2. When we stop editing, do we confirm or cancel the changes?
>
>      It feels like this decision can depend on what kind of data we are
>      editing, etc.
>
>
> I actually tend to agree with Tim here that we should probably commit
> the values when we lose focus.  This is more or less equivalent with
> what spreadsheets do -- I am only thinking about what users might compare
> this editing functionality with here, GtkTreeView is not and will not
> become a table/sheet widget ;)
>
> If applications really need confirmation via enter or something else,
> I'd say they can hook into the entry and maintain a flag whether entry
> was pressed yes or no and use that information in the "edited" callback
> to decide whether to change the model or not.
>
> Personally, I've been disliking the cell editable API, because of its
> short-comings, it's high on my list for redesigning.
>
>
> So, if there are no objections, maybe we should revert.
>
> Opinions?

Looking at the bugs that have been filed over the years, it seems clear
that there is no universal solution. We can cop out and add a
GtkCellRenderer:commit-on-focus-out property...