UITable Individual Cell Editing in App Designer

Hello All,

I wanted to put my code out there to hopefully help others in my situation that I could not find a specific answer for. I have created an app that inputs data into a UITable. The user inputs data in the "Collection Data" section and then adds it to the table as a new row with the "Add" button. Each time this is done the table is updated:

    % Value changed function: ADDButton
        function ADDButtonValueChanged(app, event)

            app.UITable.Data = app.T; %T is a private property
            
            PNP = app.PNPEditField.Value;
            Minute = app.MinuteEdit
            Field.Value;
            Trial = app.TrialEditField.Value;
            EF = app.EFEditField.Value;
            Ash = app.AshEditField.Value;
            Tar = app.TarEditField.Value;
            aMin = app.aMinEditField.Value;
            aMax = app.aMaxEditField.Value;
            R1 = app.R1EditField.Value;
            Timer = app.TimerEditField.Value;
            
            nr = {PNP Minute Trial EF Ash Tar aMin aMax R1 Timer};
            
            app.UITable.Data = [app.T; nr]; %new row added
            
            app.T = app.UITable.Data;
            
        end

This would work perfectly until I accidently added a new row with incorrect information. I made the cells of the table to be editable but when a value was changed and a new row was added the cell would go back to the original value. I also got the error that Matlab was “Unable to perform assignment because the size of the left side is x-by-x and the size of the right side is x-by-x.” if I change the value to be longer or if I wanted to delete the data that I accidently input. Therefore, I created the callback function UITableCellEdit:

                % Cell edit callback: UITable
        function UITableCellEdit(app, event)
            selectedCell = event.Indices; %cell selected
            newData = event.NewData;      %data entered
            
            if (newData > 0) 
                app.T(selectedCell(1,1),selectedCell(1,2)) = cellstr(newData); %if data is changed with different value
            else
                app.T(selectedCell(1,1),selectedCell(1,2)) = cellstr(''); %if data is to be deleted
            end    
            
        end

I had to convert the newData to be a string because otherwise I would get the error “Conversion to cell from char is not possible” and to delete the data I just made it a blank string because I would get the error “A null assignment can have only one non-colon index” when trying to assign the cell to [ ].

A lot of the posts I was reading was for deleting full rows or columns but I wanted to change a specific cell which this code now allows me to do.

I hope this helps!

[FEH]

Hi Leah

Can I know what is app.T in your coding? I face some difficulty to add new row after input data in Edit Field.

[Leah O'Shea]

In the beginning of my code I create a private property in properties (Access = private) so that I can a assign the table to that variable and allow it to be called in other functions as app.T.

properties (Access = private)

T % Table for collection

t % table for baseline values

end

Answer 1

[Voss]

"when a value was changed and a new row was added the cell would go back to the original value"

Because ADDButtonValueChanged doesn't add a new row to the uitable's existing Data; it adds a new row to app.T and sets that as the uitable's Data.

 function ADDButtonValueChanged(app, event)

    % (this sets the table's Data to app.T and is unnecessary:)
    app.UITable.Data = app.T;
    
    % ...
    % get the variables from the editfields
    % ...
    
    nr = {PNP Minute Trial EF Ash Tar aMin aMax R1 Timer};
    
    % this sets the uitable's Data to app.T followed by the new row:
    app.UITable.Data = [app.T; nr];
    
    % update app.T:
    app.T = app.UITable.Data;
    
end

To keep the existing uitable Data and add a new row, you should do:

function ADDButtonValueChanged(app, event)

    % ...
    % get the variables from the editfields
    % ...
    
    nr = {PNP Minute Trial EF Ash Tar aMin aMax R1 Timer};
    
    % this sets the uitable's Data to the existing Data followed by the new row:
    app.UITable.Data = [app.UITable.Data; nr];
    
    % (alternate expression to do the same thing:)
    % app.UITable.Data(end+1,:) = nr;
    
    % update app.T:
    app.T = app.UITable.Data;
    
end

"I had to convert the newData to be a string because otherwise I would get the error “Conversion to cell from char is not possible” and to delete the data I just made it a blank string because I would get the error “A null assignment can have only one non-colon index” when trying to assign the cell to [ ]."

Both of those errors can be avoided by using curly braces {} to access the contents of the cell:

function UITableCellEdit(app, event)
    selectedCell = event.Indices; %cell selected
    newData = event.NewData;      %data entered
    if newData > 0
        app.T{selectedCell(1,1),selectedCell(1,2)} = newData; %if data is changed with different value
    else
        app.T{selectedCell(1,1),selectedCell(1,2)} = []; %if data is to be deleted
    end    
end

Notice that that's updating app.T and not updating app.UITable.Data (so the uitable doesn't change as a result of executing this cell edit callback). You can have the function apply to the uitable by replacing app.T with app.UITable.Data in that function.

In fact, if app.T is intended to be a copy of whatever Data is in the uitable at any time, then you can remove property T from the app entirely and just use app.UITable.Data throughout to get the uitable's data whenever you need it.