VariantWidget: use toolbarview, backbutton (#924)

Saves us some hardcoded margins

Author: danirabbit

src/Widgets/VariantWidget.vala

@@ -1,6 +1,6 @@
 /*
  * SPDX-License-Identifier: GPL-3.0-or-later
- * SPDX-FileCopyrightText: 2017-2023 elementary, Inc. (https://elementary.io)
+ * SPDX-FileCopyrightText: 2017-2026 elementary, Inc. (https://elementary.io)
  */
 
 public class VariantWidget : Gtk.Frame {
@@ -11,7 +11,6 @@ public class VariantWidget : Gtk.Frame {
 
     public signal void going_to_main ();
 
-    private Gtk.Box variant_box;
     private Adw.NavigationView navigation_view;
     private Adw.NavigationPage variant_page;
 
@@ -29,47 +28,43 @@ public class VariantWidget : Gtk.Frame {
 
         var main_page = new Adw.NavigationPage (main_scrolled, main_title);
 
-        variant_listbox = new Gtk.ListBox ();
-        variant_listbox.activate_on_single_click = false;
+        variant_listbox = new Gtk.ListBox () {
+            activate_on_single_click = false
+        };
 
         var variant_scrolled = new Gtk.ScrolledWindow () {
             child = variant_listbox,
             hscrollbar_policy = NEVER,
             vexpand = true
         };
 
-        var back_button = new Gtk.Button.with_label (main_page.title) {
-            halign = START,
-            margin_top = 6,
-            margin_end = 6,
-            margin_bottom = 6,
-            margin_start = 6
+        var back_button = new Granite.BackButton (main_page.title) {
+            halign = START
         };
-        back_button.add_css_class (Granite.STYLE_CLASS_BACK_BUTTON);
 
         var variant_title = new Gtk.Label ("") {
             hexpand = true,
             justify = CENTER,
-            margin_end = 6,
-            margin_start = 6,
             mnemonic_widget = variant_listbox,
             wrap = true
         };
         variant_title.add_css_class (Granite.STYLE_CLASS_H4_LABEL);
 
-        var header_box = new Gtk.CenterBox () {
-            start_widget = back_button,
-            center_widget = variant_title,
-            hexpand = true
+        var header_box = new Gtk.HeaderBar () {
+            hexpand = true,
+            show_title_buttons = false,
+            title_widget = variant_title
         };
+        header_box.pack_start (back_button);
 
-        variant_box = new Gtk.Box (VERTICAL, 0);
-        variant_box.add_css_class (Granite.STYLE_CLASS_VIEW);
-        variant_box.append (header_box);
-        variant_box.append (new Gtk.Separator (Gtk.Orientation.HORIZONTAL));
-        variant_box.append (variant_scrolled);
+        var toolbarview = new Adw.ToolbarView () {
+            content = variant_scrolled,
+            top_bar_style = RAISED_BORDER
+        };
+        toolbarview.add_top_bar (header_box);
+        toolbarview.add_css_class (Granite.STYLE_CLASS_VIEW);
 
-        variant_page = new Adw.NavigationPage (variant_box, "");
+        variant_page = new Adw.NavigationPage (toolbarview, "");
 
         navigation_view = new Adw.NavigationView ();
         navigation_view.add (main_page);