work on ListSelector situation when items are deleted, selection should retain

Author: rjackey

test/+wt/+test/ListSelector.m

@@ -1,7 +1,7 @@
 classdef ListSelector < wt.test.BaseWidgetTest
     % Implements a unit test for a widget or component
 
-%   Copyright 2020-2025 The MathWorks Inc.
+    %   Copyright 2020-2025 The MathWorks Inc.
 
     %% Properties
     properties
@@ -19,10 +19,10 @@ function createFigure(testCase)
             testCase.createFigure@wt.test.BaseWidgetTest();
 
             % Adjust grid size
-            testCase.Figure.Position(3:4) = [500 700];
-            testCase.Grid.RowHeight = repmat({175},1,3);
+            testCase.Figure.Position(3:4) = [800 700];
+            testCase.Grid.RowHeight = repmat({175},1,4);
             testCase.Grid.ColumnWidth = {'1x','1x','1x'};
-
+            
         end %function
 
     end %methods
@@ -47,7 +47,7 @@ function setup(testCase)
 
     %% Unit Test
     methods (Test)
-            
+        
         function testProgrammaticItemsValueSelection(testCase)
 
             % Get the listbox
@@ -67,7 +67,7 @@ function testProgrammaticItemsValueSelection(testCase)
             testCase.verifyEqual(testCase.Widget.SelectedIndex, newSelIdx);
 
         end %function
-            
+        
 
         function testProgrammaticItemsDataValueSelection(testCase)
 
@@ -92,7 +92,7 @@ function testProgrammaticItemsDataValueSelection(testCase)
 
         end %function
 
-            
+        
 
         function testHighlightedValue(testCase)
 
@@ -116,7 +116,49 @@ function testHighlightedValue(testCase)
         end %function
 
 
+        
+        function testHighlightedValueOnListRemoval(testCase)
+            
+            % Get the listbox
+            listControl = testCase.Widget.ListBox;
+            
+            % Add items to the list
+            newSelIdx = [1 2 4];
+            newValue = testCase.ItemNames(newSelIdx);
+            testCase.verifySetProperty("Value", newValue);
+            testCase.verifyEqual(testCase.Widget.SelectedIndex, newSelIdx);
+            
+            % Highlight a value in the list
+            newHiliteIdx = [1 2 4];
+            newHilite = testCase.ItemNames(newHiliteIdx);
+            testCase.verifySetProperty("HighlightedValue", newHilite);
+            
+            % Remove items from list
+            testCase.Widget.Items(5) = [];
 
+            % List selection value should match
+            expValue = testCase.ItemNames([1 2 4]);
+            testCase.verifyEqual(string(listControl.Items), expValue);
+            
+            % List selection highlight should match
+            expHighlight = testCase.ItemNames([1 2 4]);
+            testCase.verifyEqual(testCase.Widget.HighlightedValue, expHighlight);
+            
+            % Remove items from list
+            testCase.Widget.Items(2) = [];
+            
+            % List selection value should match
+            expValue = testCase.ItemNames([1 4]);
+            testCase.verifyEqual(string(listControl.Items), expValue);
+            
+            % List selection highlight should match
+            expHighlight = testCase.ItemNames([1 4]);
+            testCase.verifyEqual(testCase.Widget.HighlightedValue, expHighlight);
+            
+        end %function
+        
+        
+        
         function testInteractiveSelection(testCase)
 
             % Get the listbox
@@ -146,7 +188,7 @@ function testInteractiveSelection(testCase)
         end %function
 
 
-            
+        
         function testButtonEnables(testCase)
 
             % Get the listbox and button grid
@@ -205,7 +247,7 @@ function testButtonEnables(testCase)
         end %function
 
 
-            
+        
         function testButtonFunctions(testCase)
 
             % Get the listbox and button grid
@@ -265,22 +307,22 @@ function testButtonFunctions(testCase)
 
             % Verify new highlight
             testCase.verifyEqual(w.HighlightedValue, testCase.ItemNames(1));
-           
+            
             % Verify button enables
             testCase.verifyEquality(buttonGrid.ButtonEnable(2:4), [1 0 1]);
 
         end %function
 
 
-            
+        
         function testUserButtons(testCase)
 
             % Get the widget
             w = testCase.Widget;
 
             % Add User buttons
             w.UserButtons.Icon = ["plot_24.png","play_24.png"];
-            drawnow            
+            drawnow
 
             % Press the buttons
             b = w.UserButtons.Button;
@@ -291,7 +333,7 @@ function testUserButtons(testCase)
         end %function
 
 
-            
+        
         function testStyleProperties(testCase)
 
             % Set ButtonWidth

widgets/+wt/ListSelector.m

@@ -41,6 +41,66 @@
 
     end %properties
 
+    methods
+
+        function set.Items(obj, newItems)
+
+            % Get original items and highlight
+            oldValue = obj.Value; %#ok<MCSUP>
+            oldHighlight = obj.HighlightedValue; %#ok<MCSUP>
+            
+            % What's currently selected?
+            oldLBHighlight = obj.getListBoxSelectedIndex();
+
+            % Retain the matching original value selection
+            isPresent = ismember(oldValue, newItems);
+            newValue = oldValue(isPresent);
+
+            % Retain the matching original highlight indices
+            isPresentIdx = find(isPresent);
+            newHighlightIdx = intersect(oldLBHighlight, isPresentIdx, 'stable');
+
+            % In case items were removed, we can back up to the highlight
+            % values
+            isPresent = ismember(oldHighlight, newItems);
+            newHighlight = oldHighlight(isPresent);
+
+            % Set new items
+            obj.Items = newItems;
+            % newValue = intersect(oldValue, value, 'stable')
+
+            % Set selection and highlight for consistency
+            % newHighlight = intersect(oldHighlightValue, value, 'stable')
+            obj.Value = newValue; %#ok<MCSUP>
+            % obj.HighlightedValue = newHighlight; %#ok<MCSUP>
+
+            % Set highlight for consistency
+            if obj.AllowDuplicates %#ok<MCSUP>
+                % If duplicates allowed, it can be inconsistent, so must
+                % deselect all instead
+                obj.HighlightedValue = []; %#ok<MCSUP>
+            else
+                % This is the best guess we can make
+                obj.HighlightedValue = newHighlight; %#ok<MCSUP>
+            end
+
+            % elseif isempty(newHighlightIdx)
+            % 
+            %     % Set empty selection
+            %     obj.ListBox.ValueIndex = []; %#ok<MCSUP>
+            % 
+            % else
+            % 
+            %     % Keep the same indices selected
+            %     obj.ListBox.ValueIndex = newHighlightIdx; %#ok<MCSUP>
+            % 
+            % end
+
+        end
+
+        
+    end %methods
+
 
     %% Public dependent properties
     properties (AbortSet, Dependent)
@@ -77,10 +137,12 @@
         end
 
         function value = get.Value(obj)
+            itemIdx = obj.ListBox.ItemsData;
+            itemIdx(itemIdx > numel(obj.Items)) = [];
             if isempty(obj.ItemsData)
-                value = obj.Items(:,obj.ListBox.ItemsData);
+                value = obj.Items(:, itemIdx);
             else
-                value = obj.ItemsData(:,obj.ListBox.ItemsData);
+                value = obj.ItemsData(:, itemIdx);
             end
         end
 
@@ -126,7 +188,7 @@
                 [~, obj.ListBox.Value] = ismember(value, obj.ItemsData);
             end
         end
-        
+
 
         function value = get.ButtonWidth(obj)
             value = obj.Grid.ColumnWidth{2};