update ListSelector to enable custom add callback

Author: rjackey

widgets/+wt/+enum/ListAddSource.m

@@ -0,0 +1,16 @@
+classdef ListAddSource
+    %LISTADDSOURCE Represent add selections for list widget
+    %   Enumerates a list of choices
+
+    % Copyright 2021 The MathWorks Inc.
+    
+    
+    %% Enumerations
+    enumeration
+        Items
+        Custom
+    end %enumeration
+    
+    
+end %classdef
+

widgets/+wt/ListSelector.m

@@ -37,6 +37,10 @@
         % Indicates whether to allow sort controls %RAJ - Future feature
         %Sortable  (1,1) matlab.lang.OnOffSwitchState = true
 
+        % Inidicates what to do when add button is pressed (select from
+        % Items or custom using ButtonPushed event or ButtonPushedFcn)
+        AddSource (1,1) wt.enum.ListAddSource = wt.enum.ListAddSource.Items
+        
     end %properties
 
 
@@ -152,9 +156,20 @@ function update(obj)
             obj.ListBox.Items = obj.Items(selIdx);
             obj.ListBox.ItemsData = selIdx;
 
+            % Update button enable states
+            obj.updateEnables();
+            
+        end %function
+        
+        
+        function updateEnables(obj)
+            
             % Button enables
             if obj.Enable
 
+                % What is selected?
+                selIdx = obj.SelectedIndex;
+                
                 % Highlighted selection in list?
                 hiliteIdx = obj.getListBoxSelectedIndex();
 
@@ -196,8 +211,8 @@ function onSelectionChanged(obj,evt)
                 newValue = itemsData(evt.Value);
             end
 
-            % Force update
-            obj.update();
+            % Update button enable states
+            obj.updateEnables();
 
             % Trigger event
             evtOut = wt.eventdata.ValueChangedData(newValue, oldValue);
@@ -212,7 +227,16 @@ function onButtonPushed(obj,evt)
             switch evt.Tag
 
                 case 'Add'
-                    obj.promptToAddListItems()
+                    
+                    switch obj.AddSource
+                        
+                        case wt.enum.ListAddSource.Items
+                            obj.promptToAddListItems()
+                            
+                        case wt.enum.ListAddSource.Custom
+                            notify(obj,"ButtonPushed",evt);
+                            
+                    end %switch obj.AddSource
 
                 case 'Remove'
                     obj.removeListBoxSelection();