[gnome-control-center] keyboard: Improve Empty Search State.

[Robert Ancell <rancell src gnome org>]

commit fccfb52cad36a19fca5f43bc7b12c6ac101328a2
Author: Rachit Keerti Das <rachitkdas gmail com>
Date:   Sat Feb 6 20:24:37 2021 +0530

    keyboard: Improve Empty Search State.
    
    The empty search state looks out-of place due to it being nested inside
    a listbox. This is because we can only detect empty states through
    gtk_list_filter_func().
    
    Refine it by making the empty search placeholder a child of the main stack.
    Introduce an additional helper function to detect when all the listbox
    rows would be hidden by the filter.
    
    As a part of https://gitlab.gnome.org/GNOME/gnome-control-center/-/issues/1222

 panels/keyboard/cc-keyboard-shortcut-dialog.c  | 28 ++++++--
 panels/keyboard/cc-keyboard-shortcut-dialog.ui | 92 +++++++++++++-------------
 2 files changed, 68 insertions(+), 52 deletions(-)
---
diff --git a/panels/keyboard/cc-keyboard-shortcut-dialog.c b/panels/keyboard/cc-keyboard-shortcut-dialog.c
index 178ee8692..c52013a79 100644
--- a/panels/keyboard/cc-keyboard-shortcut-dialog.c
+++ b/panels/keyboard/cc-keyboard-shortcut-dialog.c
@@ -79,6 +79,9 @@ struct _CcKeyboardShortcutDialog
  };
 
 G_DEFINE_TYPE (CcKeyboardShortcutDialog, cc_keyboard_shortcut_dialog, GTK_TYPE_DIALOG)
+static gboolean
+is_matched_shortcut_present (GtkListBox *listbox,
+                             gpointer user_data);
 
 static SectionRowData*
 section_row_data_new (const gchar *section_id,
@@ -320,12 +323,6 @@ show_shortcut_list (CcKeyboardShortcutDialog *self)
       is_custom_shortcuts = (strcmp (section_data->section_id, "custom") == 0);
       gtk_stack_set_transition_type (self->stack, GTK_STACK_TRANSITION_TYPE_SLIDE_LEFT);
     }
-
-  if (is_custom_shortcuts)
-    gtk_list_box_set_placeholder (self->shortcut_listbox, NULL);
-  else
-    gtk_list_box_set_placeholder (self->shortcut_listbox, self->empty_search_placeholder);
-
   gtk_list_box_invalidate_filter (self->shortcut_listbox);
 
   if (is_custom_shortcuts && (self->custom_shortcut_count == 0))
@@ -458,7 +455,10 @@ reset_all_clicked_cb (CcKeyboardShortcutDialog *self)
 static void
 search_entry_cb (CcKeyboardShortcutDialog *self)
 {
-  if (gtk_entry_get_text_length (GTK_ENTRY (self->search_entry)) == 0 && self->section_row == NULL)
+  gboolean is_shortcut = is_matched_shortcut_present (self->shortcut_listbox, self);
+  if (!is_shortcut)
+      gtk_stack_set_visible_child (self->stack, self->empty_search_placeholder);
+  else if (gtk_entry_get_text_length (GTK_ENTRY (self->search_entry)) == 0 && self->section_row == NULL)
     show_section_list (self);
   else if (gtk_stack_get_visible_child (self->stack) != GTK_WIDGET (self->shortcut_scrolled_window))
     show_shortcut_list (self);
@@ -664,6 +664,20 @@ shortcut_filter_function (GtkListBoxRow *row,
   return retval;
 }
 
+static gboolean
+is_matched_shortcut_present (GtkListBox* listbox,
+                             gpointer user_data)
+{
+  for (gint i = 0; ; i++)
+    {
+      GtkListBoxRow *current = gtk_list_box_get_row_at_index (listbox, i);
+      if (!current)
+        return FALSE;
+      if (shortcut_filter_function (current, user_data))
+        return TRUE;
+    }
+}
+
 static void
 shortcut_header_function (GtkListBoxRow *row,
                           GtkListBoxRow *before,
diff --git a/panels/keyboard/cc-keyboard-shortcut-dialog.ui b/panels/keyboard/cc-keyboard-shortcut-dialog.ui
index 7aefc4b72..269e97ece 100644
--- a/panels/keyboard/cc-keyboard-shortcut-dialog.ui
+++ b/panels/keyboard/cc-keyboard-shortcut-dialog.ui
@@ -28,7 +28,7 @@
                 <property name="hscrollbar_policy">never</property>
                 <property name="propagate_natural_width">True</property>
                 <property name="propagate_natural_height">True</property>
-                <property name="max_content_height">350</property>
+                <property name="max_content_height">450</property>
                 <child>
                   <object class="GtkBox">
                     <property name="visible">True</property>
@@ -58,7 +58,7 @@
                 <property name="hscrollbar_policy">never</property>
                 <property name="propagate_natural_width">True</property>
                 <property name="propagate_natural_height">True</property>
-                <property name="max_content_height">350</property>
+                <property name="max_content_height">450</property>
                 <child>
                   <object class="GtkBox">
                     <property name="visible">True</property>
@@ -137,6 +137,51 @@
                 </child>
               </object>
             </child>
+            <child>
+              <object class="GtkBox" id="empty_search_placeholder">
+              <property name="visible">True</property>
+              <property name="can_focus">False</property>
+              <property name="halign">center</property>
+              <property name="valign">center</property>
+              <property name="hexpand">True</property>
+              <property name="vexpand">True</property>
+              <property name="border_width">18</property>
+              <property name="orientation">vertical</property>
+              <property name="spacing">6</property>
+              <child>
+                <object class="GtkImage">
+                  <property name="visible">True</property>
+                  <property name="can_focus">False</property>
+                  <property name="pixel_size">80</property>
+                  <property name="icon_name">edit-find-symbolic</property>
+                  <style>
+                    <class name="dim-label"/>
+                  </style>
+                </object>
+              </child>
+              <child>
+                <object class="GtkLabel">
+                  <property name="visible">True</property>
+                  <property name="can_focus">False</property>
+                  <property name="label" translatable="yes">No keyboard shortcut found</property>
+                  <attributes>
+                    <attribute name="weight" value="bold"/>
+                    <attribute name="scale" value="1.44"/>
+                  </attributes>
+                </object>
+              </child>
+              <child>
+                <object class="GtkLabel">
+                  <property name="visible">True</property>
+                  <property name="can_focus">False</property>
+                  <property name="label" translatable="yes">Try a different search</property>
+                  <style>
+                    <class name="dim-label"/>
+                  </style>
+                </object>
+              </child>
+            </object>
+            </child>
           </object>
         </child>
       </object>
@@ -200,48 +245,5 @@
       </object>
     </child>
   </template>
-  <object class="GtkBox" id="empty_search_placeholder">
-    <property name="visible">True</property>
-    <property name="can_focus">False</property>
-    <property name="halign">center</property>
-    <property name="valign">center</property>
-    <property name="hexpand">True</property>
-    <property name="vexpand">True</property>
-    <property name="border_width">18</property>
-    <property name="orientation">vertical</property>
-    <property name="spacing">6</property>
-    <child>
-      <object class="GtkImage">
-        <property name="visible">True</property>
-        <property name="can_focus">False</property>
-        <property name="pixel_size">80</property>
-        <property name="icon_name">edit-find-symbolic</property>
-        <style>
-          <class name="dim-label"/>
-        </style>
-      </object>
-    </child>
-    <child>
-      <object class="GtkLabel">
-        <property name="visible">True</property>
-        <property name="can_focus">False</property>
-        <property name="label" translatable="yes">No keyboard shortcut found</property>
-        <attributes>
-          <attribute name="weight" value="bold"/>
-          <attribute name="scale" value="1.44"/>
-        </attributes>
-      </object>
-    </child>
-    <child>
-      <object class="GtkLabel">
-        <property name="visible">True</property>
-        <property name="can_focus">False</property>
-        <property name="label" translatable="yes">Try a different search</property>
-        <style>
-          <class name="dim-label"/>
-        </style>
-      </object>
-    </child>
-  </object>
   <object class="GtkSizeGroup" id="accelerator_sizegroup" />
 </interface>