event-editor/multi-choice: Implement GtkAccessible

This is needed to have the toggle button communicate with the
screen reader to use the parent widget to retrieve accessible
information, rather than the toggle button itself.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-calendar/-/merge_requests/603>

src/gui/event-editor/gcal-multi-choice.blp

@@ -2,6 +2,7 @@ using Gtk 4.0;
 
 template $GcalMultiChoice: Box {
   spacing: 6;
+  accessible-role: spin_button;
 
   Button down_button {
     icon-name: "pan-start-symbolic";
@@ -15,6 +16,7 @@ template $GcalMultiChoice: Box {
   }
 
   ToggleButton button {
+    accessible-role: none;
     toggled => $button_toggled_cb() swapped;
 
     styles [
@@ -23,16 +25,6 @@ template $GcalMultiChoice: Box {
       "popup",
     ]
 
-    accessibility {
-      labelled-by: [
-        template,
-      ];
-
-      described-by: [
-        template,
-      ];
-    }
-
     Stack stack {
       hexpand: true;
       vexpand: true;

src/gui/event-editor/gcal-multi-choice.c

@@ -73,7 +73,10 @@ enum
 static guint signals[LAST_SIGNAL] = { 0, };
 static GParamSpec *properties[NUM_PROPERTIES] = { NULL, };
 
-G_DEFINE_TYPE (GcalMultiChoice, gcal_multi_choice, GTK_TYPE_BOX)
+static void gcal_multi_choice_accessible_init (GtkAccessibleInterface *iface);
+
+G_DEFINE_TYPE_WITH_CODE (GcalMultiChoice, gcal_multi_choice, GTK_TYPE_BOX,
+                         G_IMPLEMENT_INTERFACE (GTK_TYPE_ACCESSIBLE, gcal_multi_choice_accessible_init))
 
 /*
  * Auxiliary methods
@@ -195,15 +198,15 @@ update_sensitivity (GcalMultiChoice *self)
 
   gtk_widget_set_can_target (self->button, has_popup);
 
-  gtk_accessible_update_property (GTK_ACCESSIBLE (self->button),
+  gtk_accessible_update_property (GTK_ACCESSIBLE (self),
                                   GTK_ACCESSIBLE_PROPERTY_HAS_POPUP, has_popup,
                                   -1);
   if (self->popover != NULL)
-    gtk_accessible_update_relation (GTK_ACCESSIBLE (self->button),
+    gtk_accessible_update_relation (GTK_ACCESSIBLE (self),
                                     GTK_ACCESSIBLE_RELATION_CONTROLS, self->popover, NULL,
                                     -1);
   else
-    gtk_accessible_reset_relation (GTK_ACCESSIBLE (self->button),
+    gtk_accessible_reset_relation (GTK_ACCESSIBLE (self),
                                    GTK_ACCESSIBLE_RELATION_CONTROLS);
 }
 
@@ -466,6 +469,19 @@ gcal_multi_choice_grab_focus (GtkWidget *widget)
   return gtk_widget_grab_focus (self->button);
 }
 
+/*
+ * GtkAccessible overrides
+ */
+
+static gboolean
+gcal_multi_choice_accessible_get_platform_state (GtkAccessible              *accessible,
+                                                 GtkAccessiblePlatformState  state)
+{
+  GcalMultiChoice *self = GCAL_MULTI_CHOICE (accessible);
+
+  return gtk_accessible_get_platform_state (GTK_ACCESSIBLE (self->button), state);
+}
+
 /*
  * Init
  */
@@ -552,6 +568,12 @@ gcal_multi_choice_class_init (GcalMultiChoiceClass *class)
   gtk_widget_class_set_css_name (widget_class, "navigator");
 }
 
+static void
+gcal_multi_choice_accessible_init (GtkAccessibleInterface *iface)
+{
+  iface->get_platform_state = gcal_multi_choice_accessible_get_platform_state;
+}
+
 static void
 gcal_multi_choice_init (GcalMultiChoice *self)
 {
@@ -733,3 +755,4 @@ gcal_multi_choice_get_popover (GcalMultiChoice *self)
 
   return GTK_POPOVER (self->popover);
 }
+