[gnome-calculator/convert-categories: 18/21] Migrated category combo to category dropdown

[Robert Roth <robertroth src gnome org>]

commit 36991c3cdba6d5dcc6c588ffe9bee5f9775a5d64
Author: Robert Roth <robert roth off gmail com>
Date:   Thu Nov 11 16:09:13 2021 +0200

    Migrated category combo to category dropdown

 src/math-converter.vala  | 24 +++++++++++-------------
 src/ui/math-converter.ui | 13 ++-----------
 2 files changed, 13 insertions(+), 24 deletions(-)
---
diff --git a/src/math-converter.vala b/src/math-converter.vala
index 65b0e341..23dfc3c4 100644
--- a/src/math-converter.vala
+++ b/src/math-converter.vala
@@ -19,7 +19,7 @@ public class MathConverter : Gtk.Grid
     private unowned Gtk.CellRendererText from_renderer;
 
     [GtkChild]
-    private unowned Gtk.ComboBox category_combo;
+    private unowned Gtk.DropDown category_combo;
     [GtkChild]
     private unowned Gtk.ComboBox from_combo;
     [GtkChild]
@@ -64,15 +64,18 @@ public class MathConverter : Gtk.Grid
     }
 
     private void build_category_model () {
-        var category_model = new Gtk.TreeStore (2, typeof (string), typeof (UnitCategory));
+        var category_model = new ListStore (typeof (UnitCategory));
         var categories = UnitManager.get_default ().get_categories ();
         foreach (var category in categories)
         {
-            Gtk.TreeIter parent;
-            category_model.append (out parent, null);
-            category_model.set (parent, 0, category.display_name, 1, category, -1);
+            category_model.append (category);
         }
         category_combo.model = category_model;
+
+        var expression = new Gtk.PropertyExpression (typeof (UnitCategory),
+                                                     null,
+                                                     "display_name");
+        category_combo.expression = expression;
     }
 
     public void set_category (string? category)
@@ -218,15 +221,10 @@ public class MathConverter : Gtk.Grid
     [GtkCallback]
     private void category_combobox_changed_cb ()
     {
-        UnitCategory? category = null;
-        Gtk.TreeIter iter;
-
-        var model = category_combo.get_model ();
-
-        if (!category_combo.get_active_iter (out iter))
-            return;
 
-        model.get (iter, 1, out category, -1);
+        UnitCategory? category  = category_combo.selected_item as UnitCategory;
+        print ("%s\n", category.name);
+        // set_category (category.name);
 
     }
 
diff --git a/src/ui/math-converter.ui b/src/ui/math-converter.ui
index 73be0e00..21006d6a 100644
--- a/src/ui/math-converter.ui
+++ b/src/ui/math-converter.ui
@@ -13,17 +13,8 @@
         <property name="hexpand">True</property>
         <property name="vexpand">False</property>
         <child>
-          <object class="GtkComboBox" id="category_combo">
-            <property name="hexpand">False</property>
-            <signal name="changed" handler="category_combobox_changed_cb" swapped="no"/>
-            <child>
-              <object class="GtkCellRendererText" id="category_renderer">
-                <property name="ellipsize">end</property>
-              </object>
-              <attributes>
-                <attribute name="text">0</attribute>
-              </attributes>
-            </child>
+          <object class="GtkDropDown" id="category_combo">
+            <signal name="notify::selected" handler="category_combobox_changed_cb" swapped="no"/>
           </object>
         </child>
         <child>