MATLAB: App Designer: How to delete items from listbox

app designerlistbox

Hello everybody,
I want to make it possible to delete the selected item of a listbox by pushing a button. I'm using App Designer.
With the following code I'm getting the error message "Matrix index is out of range for deletion.". But if the first item is selected, nothing happens at all.
% Button pushed function: deleteButton
        function deleteButtonPushed(app, event)
            hListBox = app.ListBox;
            currentItems = get(hListBox);
            [~, index] = ismember(hListBox.Value, hListBox.Items);
            newItems = currentItems;
            newItems(index) = [];
            set(hListBox,newItems);
     
        end
So, I guess that's not the way to delete. So I tried to replace the selected item by another one. Just to test if it's possible to change anything in the listbox 
        newItems(index) = newItems(end);
        set(hListBox,newItems);
Like this, I get the following message:
"Error using matlab.ui.control.ListBox/set You cannot set the read-only property 'BeingDeleted' of ListBox."
Can somebody help me? After trying and googling for hours, I'm not even sure if it's possible to change anything in the listbox at runtime.
(Matlab R2018b)
Thank you!!

Best Answer

Hi Marie,
Below code will delete your corresponding item. 
 function ButtonPushed(app, event)
            [~,idx] = ismember(app.ListBox.Value,app.ListBox.Items);
            app.ListBox.Items(idx) = [];
 end
The below part in your code currentItems will give you the properties of the list box not the Item List in the listbox.
That's how get method works. Get method, gets the properties of the object you are referring in a struct. So that's why you see an error, you can see but you can't set all of the properties of an object because some of them might be protected. 
hListBox = app.ListBox;
currentItems = get(hListBox);
When you debug your code(put red dot inside the pushbutton callback and evaluate the line currentItems = get(hListBox) with one step forward), you will see currentItems will give you the below properties: 
currentItems = 
  struct with fields:
         Multiselect: 'off'
               Value: 'Item 1'
               Items: {'Item 1'  'Item 3'  'Item 4'}
           ItemsData: []
     ValueChangedFcn: [function_handle]
              Parent: [1×1 Figure]
    HandleVisibility: 'on'
          BusyAction: 'queue'
        BeingDeleted: 'off'
       Interruptible: 'on'
           CreateFcn: ''
           DeleteFcn: ''
                Type: 'uilistbox'
                 Tag: ''
            UserData: []
              Enable: 'on'
             Visible: 'on'
            FontName: 'Helvetica'
            FontSize: 12
          FontWeight: 'normal'
           FontAngle: 'normal'
           FontColor: [0 0 0]
     BackgroundColor: [1 1 1]
       InnerPosition: [147 333 100 74]
            Position: [147 333 100 74]
       OuterPosition: [147 333 100 74]
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