disable playback when there's nothing in the timeline

tests/examples/ges-ui.c

@@ -33,6 +33,7 @@ typedef struct App
   GtkWidget *properties;
   GList *selected_objects;
   int n_selected;
+  int n_objects;
   GtkHScale *duration;
   GtkHScale *in_point;
   GtkAction *add_file;
@@ -413,6 +414,12 @@ desc_for_object (GESTimelineObject * object)
   return uri;
 }
 
+static void
+object_count_changed (App * app)
+{
+  gtk_action_set_sensitive (app->play, app->n_objects > 0);
+}
+
 static void
 layer_object_added_cb (GESTimelineLayer * layer, GESTimelineObject * object,
     App * app)
@@ -430,6 +437,8 @@ layer_object_added_cb (GESTimelineLayer * layer, GESTimelineObject * object,
   g_signal_connect (G_OBJECT (object), "notify::duration",
       G_CALLBACK (timeline_object_notify_duration_cb), app);
   timeline_object_notify_duration_cb (object, NULL, app);
+  app->n_objects++;
+  object_count_changed (app);
 }
 
 static void
@@ -444,6 +453,8 @@ layer_object_removed_cb (GESTimelineLayer * layer, GESTimelineObject * object,
     g_print ("object deleted but we don't own it");
     return;
   }
+  app->n_objects--;
+  object_count_changed (app);
 
   gtk_list_store_remove (app->model, &iter);
 }

tests/examples/ges-ui.glade

@@ -99,8 +99,9 @@
                     <child>
                       <object class="GtkImageMenuItem" id="delete_item">
                         <property name="visible">True</property>
-                        <property name="use_action_appearance">True</property>
                         <property name="related_action">delete</property>
+                        <property name="use_action_appearance">True</property>
+                        <property name="use_underline">True</property>
                         <property name="use_stock">True</property>
                       </object>
                     </child>
@@ -126,8 +127,9 @@
                     <child>
                       <object class="GtkImageMenuItem" id="add_file_item">
                         <property name="visible">True</property>
-                        <property name="use_action_appearance">True</property>
                         <property name="related_action">add_file</property>
+                        <property name="use_action_appearance">True</property>
+                        <property name="use_underline">True</property>
                         <property name="use_stock">True</property>
                       </object>
                     </child>
@@ -139,8 +141,10 @@
                     <child>
                       <object class="GtkImageMenuItem" id="menuitem2">
                         <property name="visible">True</property>
-                        <property name="use_action_appearance">True</property>
                         <property name="related_action">play</property>
+                        <property name="use_action_appearance">True</property>
+                        <property name="use_underline">True</property>
+                        <property name="use_stock">True</property>
                       </object>
                     </child>
                   </object>
@@ -179,8 +183,8 @@
             <child>
               <object class="GtkToolButton" id="add_button">
                 <property name="visible">True</property>
-                <property name="related_action">add_file</property>
                 <property name="use_action_appearance">True</property>
+                <property name="related_action">add_file</property>
                 <property name="label" translatable="yes">toolbutton1</property>
                 <property name="use_underline">True</property>
               </object>
@@ -192,8 +196,8 @@
             <child>
               <object class="GtkToolButton" id="delete_button">
                 <property name="visible">True</property>
-                <property name="related_action">delete</property>
                 <property name="use_action_appearance">True</property>
+                <property name="related_action">delete</property>
                 <property name="label" translatable="yes">Delete</property>
                 <property name="use_underline">True</property>
               </object>
@@ -214,8 +218,8 @@
             <child>
               <object class="GtkToolButton" id="play_button">
                 <property name="visible">True</property>
-                <property name="related_action">play</property>
                 <property name="use_action_appearance">True</property>
+                <property name="related_action">play</property>
                 <property name="label" translatable="yes">toolbutton1</property>
                 <property name="use_underline">True</property>
               </object>
@@ -397,8 +401,8 @@
   <object class="GtkTreeSelection" id="selection"/>
   <object class="GtkSizeGroup" id="LabelSizeGroup">
     <widgets>
-      <widget name="label_inpoint"/>
       <widget name="label_duration"/>
+      <widget name="label_inpoint"/>
     </widgets>
   </object>
   <object class="GtkAction" id="delete">
@@ -416,6 +420,7 @@
   <object class="GtkAction" id="play">
     <property name="label">Play</property>
     <property name="stock_id">gtk-media-play</property>
+    <property name="sensitive">False</property>
     <property name="always_show_image">True</property>
     <signal name="activate" handler="play_activate_cb"/>
   </object>