[gnome-control-center/wip/carlosg/wacom-empty-state] wacom: Bring back empty state view

[Carlos Garnacho <carlosg src gnome org>]

commit d055bfd2204374fd6d25d81a87b4fd03719ca80f
Author: Carlos Garnacho <carlosg gnome org>
Date:   Mon Feb 28 19:23:23 2022 +0100

    wacom: Bring back empty state view
    
    This went mistakenly missing in the recent UI updates. Since this
    panel is still accessible through search despite tablet availability,
    we should have a proper empty state view when moving to the panel
    with no tablets available.
    
    Fixes: https://gitlab.gnome.org/GNOME/gnome-control-center/-/issues/1684

 panels/wacom/cc-wacom-panel.c  | 18 +++++++++++++++
 panels/wacom/cc-wacom-panel.ui | 52 ++++++++++++++++++++++++++----------------
 2 files changed, 50 insertions(+), 20 deletions(-)
---
diff --git a/panels/wacom/cc-wacom-panel.c b/panels/wacom/cc-wacom-panel.c
index 0c808c24b..05592f3ea 100644
--- a/panels/wacom/cc-wacom-panel.c
+++ b/panels/wacom/cc-wacom-panel.c
@@ -49,6 +49,9 @@ struct _CcWacomPanel
        GtkWidget        *scrollable;
        GtkWidget        *tablets;
        GtkWidget        *styli;
+       GtkWidget        *initial_state_stack;
+       GtkWidget        *panel_view;
+       GtkWidget        *panel_empty_state;
        GHashTable       *devices; /* key=GsdDevice, value=CcWacomDevice */
        GHashTable       *pages; /* key=CcWacomDevice, value=GtkWidget */
        GHashTable       *stylus_pages; /* key=CcWacomTool, value=GtkWidget */
@@ -348,6 +351,15 @@ update_test_button (CcWacomPanel *self)
        }
 }
 
+static void
+update_initial_state (CcWacomPanel *self)
+{
+       gtk_stack_set_visible_child (GTK_STACK (self->initial_state_stack),
+                                    g_hash_table_size (self->devices) == 0 ?
+                                    self->panel_empty_state :
+                                    self->panel_view);
+}
+
 static void
 update_highlighted_stylus (CcWacomPanel *panel,
                           CcWacomTool  *stylus)
@@ -520,6 +532,9 @@ cc_wacom_panel_class_init (CcWacomPanelClass *klass)
        gtk_widget_class_bind_template_child (widget_class, CcWacomPanel, test_draw_area);
        gtk_widget_class_bind_template_child (widget_class, CcWacomPanel, tablets);
        gtk_widget_class_bind_template_child (widget_class, CcWacomPanel, styli);
+       gtk_widget_class_bind_template_child (widget_class, CcWacomPanel, initial_state_stack);
+       gtk_widget_class_bind_template_child (widget_class, CcWacomPanel, panel_empty_state);
+       gtk_widget_class_bind_template_child (widget_class, CcWacomPanel, panel_view);
        gtk_widget_class_bind_template_child (widget_class, CcWacomPanel, vadjustment);
 }
 
@@ -582,6 +597,7 @@ device_removed_cb (CcWacomPanel     *self,
        g_hash_table_remove (self->devices, gsd_device);
        check_remove_stylus_pages (self);
        update_test_button (self);
+       update_initial_state (self);
 }
 
 static void
@@ -590,6 +606,7 @@ device_added_cb (CcWacomPanel *self,
 {
        add_known_device (self, device);
        update_test_button (self);
+       update_initial_state (self);
 }
 
 void
@@ -663,6 +680,7 @@ cc_wacom_panel_init (CcWacomPanel *self)
                add_known_device (self, l->data);
 
        update_test_button (self);
+       update_initial_state (self);
 }
 
 GDBusProxy *
diff --git a/panels/wacom/cc-wacom-panel.ui b/panels/wacom/cc-wacom-panel.ui
index 28a9d79b6..77e7e16a9 100644
--- a/panels/wacom/cc-wacom-panel.ui
+++ b/panels/wacom/cc-wacom-panel.ui
@@ -15,34 +15,46 @@
     </child>
 
     <child type="content">
-      <object class="GtkScrolledWindow">
-        <property name="hscrollbar-policy">never</property>
-        <property name="vadjustment">vadjustment</property>
+      <object class="GtkStack" id="initial_state_stack">
+        <property name="transition_duration">0</property>
         <child>
-          <object class="AdwClamp" id="scrollable">
-            <property name="margin_top">32</property>
-            <property name="margin_bottom">32</property>
-            <property name="margin_start">12</property>
-            <property name="margin_end">12</property>
-
+          <object class="GtkScrolledWindow" id="panel_view">
+            <property name="hscrollbar-policy">never</property>
+            <property name="vadjustment">vadjustment</property>
             <child>
-              <object class="GtkBox">
-                <property name="spacing">48</property>
-                <property name="orientation">vertical</property>
+              <object class="AdwClamp" id="scrollable">
+                <property name="margin_top">32</property>
+                <property name="margin_bottom">32</property>
+                <property name="margin_start">12</property>
+                <property name="margin_end">12</property>
+
                 <child>
-                  <object class="GtkBox" id="tablets">
-                    <property name="orientation">vertical</property>
+                  <object class="GtkBox">
                     <property name="spacing">48</property>
-                 </object>
-                </child>
-                <child>
-                  <object class="GtkBox" id="styli">
                     <property name="orientation">vertical</property>
-                    <property name="spacing">48</property>
-                 </object>
+                    <child>
+                      <object class="GtkBox" id="tablets">
+                        <property name="orientation">vertical</property>
+                        <property name="spacing">48</property>
+                      </object>
+                    </child>
+                    <child>
+                      <object class="GtkBox" id="styli">
+                        <property name="orientation">vertical</property>
+                        <property name="spacing">48</property>
+                      </object>
+                    </child>
+                  </object>
                 </child>
               </object>
             </child>
+         </object>
+       </child>
+       <child>
+          <object class="AdwStatusPage" id="panel_empty_state">
+            <property name="icon-name">input-tablet-symbolic</property>
+            <property name="title" translatable="yes">No tablet detected</property>
+            <property name="description" translatable="yes">Please plug in or turn on your Wacom 
tablet.</property>
           </object>
         </child>
       </object>