How to prevent scrolling to change the value on SpinButton

[Charles]

Seems that when the SpinButton is created, an EventControllerScroll is added too. So that users can change the value of SpinButton by scrolling.

But I often change it accidentally.

How can I remove EventControllerScroll from SpinButton? I can do this by looping Widget.observe_controllers() and then remove it.

But the doc says:

Applications should try hard to avoid calling this function
because of the slowdowns.

So is there other better ways to stop scoll to change the value of SpinButton?

[roger.matthews]

g_signal_connect(spinbutton, “scroll-event”, G_CALLBACK(gtk_true), NULL);

[ebassi (Emmanuele Bassi)]

The scroll-event signal is only available on widgets if you’re using GTK3, but since @Charles is referring to the observe_controllers() method, they are using GTK4.

[ebassi (Emmanuele Bassi)]

Do not ever remove internal objects from a GTK widget: things are going to break, horribly, and there is no expectation that what you do is supported in any way.

@Charles

So is there other better ways to stop scoll to change the value of SpinButton?

You could add a scroll event controller on the parent widget of the spin button, using the capture phase, and prevent any scroll event from reaching the spin button.

[Charles]

@ebassi

You could add a scroll event controller on the parent widget of the spin button, using the capture phase

I added a Gtk.EventControllerScroll on the parent widget GtkBox:

This is the properties on the added Gtk.EventControllerScroll:

The code is:

_newBox(properties) {
        const box = new Gtk.Box({
            spacing: 6,
            margin_top: 6,
            margin_bottom: 6,
            margin_start: 6,
            margin_end: 6,
        })
        Object.assign(box, properties);
        return box;
}

const boxLeft = this._newBox({
  hexpand: true,
  halign: Gtk.Align.START
});

// Add a spin button on boxLeft
boxLeft.append(this._newSpinButton());

// add a Gtk.EventControllerScroll on boxLeft
const controller = new Gtk.EventControllerScroll();
// Prevent the scroll event of the spin button inside the boxLeft? It's not working
controller.set_propagation_phase(Gtk.PropagationPhase.CAPTURE);
controller.connect('scroll', () => {
    // Can't receive this event while scroll on the spin button added on the boxLeft
    log('Scrolling..')
    return Gdk.EVENT_STOP;
});
boxLeft.add_controller(controller);

@ebassi

and prevent any scroll event from reaching the spin button.

The above code is not working. Am I missing something important?