what is wrong with this small app?

Hi

I am trying to play around with my small list in this app but it seems matlab is not accepting my code.

Can anybody tell me whats wrong in it?

[Matt J]

What would we need to do to observe the problem?

[Muazma Ali]

hi @Matt J when I choose the first three elements from the list, the lamp is supposed to to turn to green. But I think I havent set up the criterion right in the app...

Could you check it , I would be very thankful. Actually I had programmed a list in my matlab program with result coming up as numbers and based on those numbers I had set up some conditions but when I started on the app, I had to use the list from the canvas then I could nt use the programmed once, :(

Answer 1

[Praveen Reddy]

Hi Mauzama,

I understand that you want to make the lamp glow green whenever user selects the first three values from the “ListBox”. In the call back function I could observe that you are comparing “value” with string, but “value” is a cell array of all the selected items.

if (strcmpi(value, 'CaCl2') && strcmpi(value,'MgCl2') && strcmpi(value, 'NH4Cl')) 
        app.Lamp.Color='g';  
else
        app.Lamp.Color='r';
end 

Modify the if condition in the call back function as below

% Value changed function: ListBox
function ListBoxValueChanged(app, event)
   value = app.ListBox.Value; 
   if(any(ismember(value,'CaCl2')) && any(ismember(value,'MgCl2')) && any(ismember(value,'NH4Cl')))
       app.Lamp.Color='g';
   else
       app.Lamp.Color='r';
   end
end

To know more about “ismember” and “any” functions, please refer to the following MATLAB documentation

• https://www.mathworks.com/help/matlab/ref/double.ismember.html
• https://www.mathworks.com/help/matlab/ref/any.html

I hope the above information resolves your query.