implemented the calls to the preload() function; this closes #2012

campcaster/src/modules/widgets/include/LiveSupport/Widgets/ZebraTreeView.h

@@ -150,6 +150,16 @@ class ZebraTreeView : public Gtk::TreeView
             signalCellEdited().emit(path, columnId, newText);
         }
 
+        /**
+         *  Emit the "tree model has changed" signal.
+         */
+        void
+        emitSignalTreeModelChanged(void)
+                                                                throw ()
+        {
+            signalTreeModelChanged().emit();
+        }
+
         /**
          *  Renumber the rows after they have changed.
          *
@@ -181,6 +191,11 @@ class ZebraTreeView : public Gtk::TreeView
                      int, 
                      const Glib::ustring &>     signalCellEditedObject;
 
+        /**
+         *  A signal object to notify people that the tree model has changed.
+         */
+        sigc::signal<void>                      signalTreeModelChangedObject;
+
         /**
          *  Event handler for the row_inserted signal.
          *
@@ -397,6 +412,19 @@ class ZebraTreeView : public Gtk::TreeView
             return signalCellEditedObject;
         }
 
+        /**
+         *  The signal raised when the rows in the tree model have changed.
+         *  This signal is emitted whenever the tree model emits a
+         *  row_inserted, row_deleted or rows_reordered signal.
+         *
+         *  @return the signal object (a protected member of this class)
+         */
+        sigc::signal<void>
+        signalTreeModelChanged(void)                            throw ()
+        {
+            return signalTreeModelChangedObject;
+        }
+
         /**
          *  Manually connect the 'model has changed' signals to the tree view.
          *  This is useful if you want to use the same ZebraTreeView object

campcaster/src/modules/widgets/src/ZebraTreeView.cxx

@@ -501,6 +501,7 @@ ZebraTreeView :: onRowInserted(const Gtk::TreeModel::Path &      path,
 {
     renumberRows();
     columns_autosize();
+    emitSignalTreeModelChanged();
 }
 
 
@@ -513,6 +514,7 @@ ZebraTreeView :: onRowDeleted(const Gtk::TreeModel::Path &      path)
 {
     renumberRows();
     columns_autosize();
+    emitSignalTreeModelChanged();
 }
 
 
@@ -526,6 +528,7 @@ ZebraTreeView :: onRowsReordered(const Gtk::TreeModel::Path &      path,
                                                                     throw ()
 {
     renumberRows();
+    emitSignalTreeModelChanged();
 }
 
 

campcaster/src/products/gLiveSupport/src/LiveModeWindow.cxx

@@ -112,6 +112,8 @@ LiveModeWindow :: LiveModeWindow (Ptr<GLiveSupport>::Ref    gLiveSupport,
                                         &LiveModeWindow::onEntryClicked));
     treeView->signal_row_activated().connect(sigc::mem_fun(*this,
                                         &LiveModeWindow::onDoubleClick));
+    treeView->signalTreeModelChanged().connect(sigc::mem_fun(*this,
+                                        &LiveModeWindow::onTreeModelChanged));
     
     // register the signal handler for keyboard key presses
     treeView->signal_key_press_event().connect(sigc::mem_fun(*this,
@@ -197,10 +199,7 @@ void
 LiveModeWindow :: addItem(Ptr<Playable>::Ref  playable)             throw ()
 {
     addItem(treeModel->append(), playable);
-    
+    onTreeModelChanged();
-    if (treeModel->children().size() == 1) {
-        preloadNextItem();
-    }
 }
 
 
@@ -272,22 +271,6 @@ LiveModeWindow :: popTop(void)                                      throw ()
 }
 
 
-/*------------------------------------------------------------------------------
- *  Preload the item at the top of the window.
- *----------------------------------------------------------------------------*/
-void
-LiveModeWindow :: preloadNextItem(void)                             throw ()
-{
-    Ptr<Playable>::Ref          playable;
-    Gtk::TreeModel::iterator    iter = treeModel->children().begin();
-    
-    if (iter) {
-        playable = (*iter)[modelColumns.playableColumn];
-        gLiveSupport->preload(playable);
-    }
-}
-
-
 /*------------------------------------------------------------------------------
  *  Find the selected row.
  *----------------------------------------------------------------------------*/
@@ -669,6 +652,28 @@ LiveModeWindow :: onRemoveItemButtonClicked(void)                   throw ()
 }
 
 
+/*------------------------------------------------------------------------------
+ *  Signal handler for a change in the tree model.
+ *----------------------------------------------------------------------------*/
+void
+LiveModeWindow :: onTreeModelChanged(void)                          throw ()
+{
+    Gtk::TreeModel::iterator    iter = treeModel->children().begin();
+    
+    if (iter) {
+        Ptr<Playable>::Ref      playable = (*iter)[modelColumns.playableColumn];
+        if (playable) {
+            if (!savedTopPlayable || savedTopPlayable &&
+                    *savedTopPlayable->getId() != *playable->getId()) {
+                gLiveSupport->preload(playable);
+            }
+            savedTopPlayable = playable;
+        }
+        
+    }
+}
+
+
 /*------------------------------------------------------------------------------
  *  Event handler called when the the window gets hidden.
  *----------------------------------------------------------------------------*/

campcaster/src/products/gLiveSupport/src/LiveModeWindow.h

@@ -81,6 +81,11 @@ using namespace LiveSupport::Widgets;
 class LiveModeWindow : public GuiWindow
 {
     private:
+        /**
+         *  The Playable item at the top of the window.
+         */
+        Ptr<Playable>::Ref                  savedTopPlayable;
+
         /**
          *  The Export Playlist pop-up window.
          */
@@ -280,6 +285,12 @@ class LiveModeWindow : public GuiWindow
         virtual void
         onRemoveItemButtonClicked(void)                         throw ();
 
+        /**
+         *  Signal handler for a change in the tree model.
+         */
+        virtual void
+        onTreeModelChanged(void)                                throw ();
+
         /**
          *  Event handler called when the the window gets hidden.
          *
@@ -341,13 +352,6 @@ class LiveModeWindow : public GuiWindow
         Ptr<Playable>::Ref
         popTop(void)                                            throw ();
 
-        /**
-         *  Preload the item at the top of the window.
-         *  This is to shorten the time a playlist takes to start.
-         */
-        void
-        preloadNextItem()                                       throw ();
-
         /**
          *  Update the cue player display to show a stopped state.
          */