[gnome-builder/wip/gtk4-port] plugins/editorui: fix selection/focus of scheme preview

[Christian Hergert <chergert src gnome org>]

commit 127d8e49a7b221576bfb029c346fc505c1acda70
Author: Christian Hergert <chergert redhat com>
Date:   Mon Apr 4 15:39:07 2022 -0700

    plugins/editorui: fix selection/focus of scheme preview

 .../editorui/gbp-editorui-preferences-addin.c      | 31 ++++++++++++++++++++++
 1 file changed, 31 insertions(+)
---
diff --git a/src/plugins/editorui/gbp-editorui-preferences-addin.c 
b/src/plugins/editorui/gbp-editorui-preferences-addin.c
index c1260c21d..113578135 100644
--- a/src/plugins/editorui/gbp-editorui-preferences-addin.c
+++ b/src/plugins/editorui/gbp-editorui-preferences-addin.c
@@ -124,6 +124,30 @@ compare_section (gconstpointer a,
   return g_strcmp0 (pagea->section, pageb->section);
 }
 
+static void
+notify_style_scheme_cb (IdeApplication *app,
+                        GParamSpec     *pspec,
+                        GtkFlowBox     *flowbox)
+{
+  const char *style_scheme;
+
+  g_assert (IDE_IS_APPLICATION (app));
+  g_assert (GTK_IS_FLOW_BOX (flowbox));
+
+  style_scheme = ide_application_get_style_scheme (app);
+
+  for (GtkWidget *child = gtk_widget_get_first_child (GTK_WIDGET (flowbox));
+       child != NULL;
+       child = gtk_widget_get_next_sibling (child))
+    {
+      GtkSourceStyleSchemePreview *preview = GTK_SOURCE_STYLE_SCHEME_PREVIEW (gtk_flow_box_child_get_child 
(GTK_FLOW_BOX_CHILD (child)));
+      GtkSourceStyleScheme *scheme = gtk_source_style_scheme_preview_get_scheme (preview);
+      gboolean selected = g_strcmp0 (style_scheme, gtk_source_style_scheme_get_id (scheme)) == 0;
+
+      gtk_source_style_scheme_preview_set_selected (preview, selected);
+    }
+}
+
 static void
 ide_preferences_builtin_add_schemes (const char                   *page_name,
                                      const IdePreferenceItemEntry *entry,
@@ -192,6 +216,13 @@ ide_preferences_builtin_add_schemes (const char                   *page_name,
       gtk_flow_box_append (flowbox, selector);
     }
 
+  g_signal_connect_object (IDE_APPLICATION_DEFAULT,
+                           "notify::style-scheme",
+                           G_CALLBACK (notify_style_scheme_cb),
+                           flowbox,
+                           0);
+  notify_style_scheme_cb (IDE_APPLICATION_DEFAULT, NULL, flowbox);
+
   adw_preferences_group_add (group, GTK_WIDGET (flowbox));
 }