Re: [Builder] Adding Handlers from the GUI Builder

[Christian Hergert <christian hergert me>]

On 06/18/2019 03:23 PM, David Strauss wrote:
> I'm having trouble adding handlers to components I'm graphically 
> editing, and I'm not sure if I'm running into a bug or just part of the 
> Builder learning curve.
>
> Let's say I have an ApplicationWindow with a GtkSwitch widget. While the 
> GtkSwitch has focus in the GUI editor, at the bottom of the Builder 
> window, I select the "Signals" tab. For "state-set", I configure a 
> handler: "_on_set_state". Yet, I don't see the handler written to the 
> XML for the window. Finally, I add a callback method to the 
> corresponding Python class with the @Gtk.Template.Callback() decorator.
>
> If I run the app, I get "RuntimeError: Handler '_on_set_state' was 
> declared with @Gtk.Template.Callback but was not present in template".
>
> I feel like the XML should get the following added to <object 
> class="GtkSwitch">:
>
> <signal name="state-set" handler="_on_state_set" swapped="no"/>
>
> I actually see nothing written to the project, and the signal is missing 
> if I re-open the project in Builder.

Possibly two things:

 * You didn't tab out of the cell after adding the text (you should know
   by if it added a new empty row below). It's just how the glade editor
   works, even though it's a bit annoying.
 * The .ui file didn't get saved. This one is pretty annoying and has to
   do with some cases where our key-press are hijacked and we can't
   activate the Save action. If that happened, just click somewhere on
   the UI design and hit Ctrl+s to save.

-- Christian