return value of categorical array in uitable- Matlab App Designer

Hi Guys, im just working on a GUI with Matlab App Designer. Ive added some UITables with categorical arrays to have drop menues in my tables. Therefore i defined the cells like "cell = categorical({'on'}, {'on','off'})", to have a default value in the drop down. The issue is that the return value of the cell is "1x1 categorical" when im not changing the default value, but if i made any changes on the drop down i get only a char value from the cell. Why does matlab do this cast operation? Is there a way to get a categorical array for any case?

Best regards

Answer 1

[Riya]

Hi, 

I understand that you want to return categorical values when the dropdown value changes.

It happens because MATLAB treats dropdown values as editable strings instead of preserving their data type.  

To consistently return categorical values, you can consider adding “CellEditCallback” function for your “UITable” component:

function UITable_CellEdit(app, event) 
row = event.Indices(1); 
col = event.Indices(2); 
newValue = event.NewData; 

% If the column is supposed to be categorical, convert back 
if col == 1 % assuming first column is categorical 
    validCats = {'on', 'off'}; 
    app.UITable.Data{row, col} = categorical({newValue}, validCats); 
end 
end 

If you have multiple categorical columns, you can maintain a map or array and apply the conversion accordingly.

For more information about callbacks in App designer, refer the following documentation:

web(fullfile(docroot, 'matlab/creating_guis/write-callbacks-for-gui-in-app-designer.html'))