[gnome-games/wip/exalm/libhandy2: 1/9] ui: Add subpage transition for PreferencesWindow

[Alexander Mikhaylenko <alexm src gnome org>]

commit a09f22066a8e65b1351fd3c8c9d8ddc3d79a43a4
Author: Alexander Mikhaylenko <exalm7659 gmail com>
Date:   Wed Sep 12 13:13:59 2018 +0500

    ui: Add subpage transition for PreferencesWindow
    
    Also keep previous subpage around during the transition, and only remove
    it after it has finished.

 data/ui/preferences-window.ui  |  3 +++
 src/ui/preferences-window.vala | 16 +++++++++++++---
 2 files changed, 16 insertions(+), 3 deletions(-)
---
diff --git a/data/ui/preferences-window.ui b/data/ui/preferences-window.ui
index e5f50fbb..0b9e4c3e 100644
--- a/data/ui/preferences-window.ui
+++ b/data/ui/preferences-window.ui
@@ -10,6 +10,7 @@
     <child type="titlebar">
       <object class="GtkStack" id="titlebar_stack">
         <property name="visible">True</property>
+        <property name="transition-type">GTK_STACK_TRANSITION_TYPE_SLIDE_LEFT_RIGHT</property>
         <child>
           <object class="GtkBox" id="titlebar_box">
             <property name="visible">True</property>
@@ -43,6 +44,8 @@
     <child>
       <object class="GtkStack" id="main_stack">
         <property name="visible">True</property>
+        <property name="transition-type">GTK_STACK_TRANSITION_TYPE_SLIDE_LEFT_RIGHT</property>
+        <signal name="notify::transition-running" handler="subpage_transition_finished"/>
         <child>
           <object class="GtkBox" id="content_box">
             <property name="visible">True</property>
diff --git a/src/ui/preferences-window.vala b/src/ui/preferences-window.vala
index 0698d2d6..904544a9 100644
--- a/src/ui/preferences-window.vala
+++ b/src/ui/preferences-window.vala
@@ -15,6 +15,8 @@ private class Games.PreferencesWindow : Gtk.Window {
        [GtkChild]
        private Gtk.Stack stack;
 
+       private PreferencesSubpage previous_subpage;
+
        private PreferencesSubpage _subpage;
        public PreferencesSubpage subpage {
                get { return _subpage; }
@@ -23,11 +25,9 @@ private class Games.PreferencesWindow : Gtk.Window {
                                return;
 
                        if (subpage != null) {
+                               previous_subpage = subpage;
                                main_stack.visible_child = content_box;
                                titlebar_stack.visible_child = titlebar_box;
-
-                               main_stack.remove (subpage);
-                               titlebar_stack.remove (subpage.header_bar);
                        }
 
                        if (value != null) {
@@ -67,4 +67,14 @@ private class Games.PreferencesWindow : Gtk.Window {
                subpage_binding = page.bind_property ("subpage", this, "subpage",
                                                      BindingFlags.SYNC_CREATE);
        }
+
+       [GtkCallback]
+       public void subpage_transition_finished (Object object, ParamSpec param) {
+               if (main_stack.transition_running || previous_subpage == null)
+                       return;
+
+               main_stack.remove (previous_subpage);
+               titlebar_stack.remove (previous_subpage.header_bar);
+               previous_subpage = null;
+       }
 }