I'm trying to create a shopping list using buttons and am having trouble getting my list to stack items

What I want the program to do:

Click the meal that you want to add to the list --> The button callback f'n adds to the global list --> Click done and the total list of ingredients prints to the command window

What I have tried is making a matrix that will be added to by each button TOTAL=zeros(25,1). (For 25 ingredients). When I hit the button it does add to TOTAL, but if I hit another button it adds to the original TOTAL which is just all zeros.

Here is the global matrix:

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

ING=['Onion';'Garlic';'Eggs'; 'Bell Pepper';'Oatmeal';'Pasta';'Pasta Sause';'Mushrooms';'Cornmeal';'Self Rise Flour';'Canned Milk';'Sour Cream'; 'Milk';'Cream Corn';'Bagel';'Cereal';'Kidney Beans';'Black Beans';'Ground Beef';'Tomato Paste';'Cornbeef';'Cabage';'Carrots'];
TOTAL=[0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0]; %the zeros coorespond to the quantity.

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

This is my button callback:

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

function oatmeal_fn(Oatmeal_h, evt, TOTAL)
  ing=['Oatmeal'];
  quant=[0;0;0;0;1;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0];
   TOTAL+quant
endfunction

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

It adds the matrices correctly but when I click another button it adds to the original total.

[Kevin Phung]

I have some comments if you can you clarify:

function oatmeal_fn(Oatmeal_h, evt, TOTAL)
  ing=['Oatmeal']; %where does this come into play?
  quant=[0;0;0;0;1;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0];
   TOTAL+quant %is this not being stored anywhere?
end

%do you have a callback function for every ingredient list?

[Andrew Lorick]

ing was going to be in a strcat(ing,num2str(quant)), but I abandoned that until I could solve the problem stated above. What do you mean by TOTAL+quant being stored? should TOTAL be a function? I have callbacks for all the other menu items.

[Kevin Phung]

no, I was just confused as to what the purpose of that line was. Because current that just outputs the result to the command window, whereas your goal is to continously update the total quantity, and you can do that by storing it in the user data property of your gui. do you have any questions regarding my suggestion below?

[Walter Roberson]

You should be asking your question on the Octave mailing list, as we do not have the resources to deal with Octave here.

(endfunction is never used in MATLAB.)

[Andrew Lorick]

Shoot! My cover's blown!! Haha, it didn't even occur to me to ask on the Octave forums until after I posted the question. I've learned lots though, so thank you!

Answer 1

[Kevin Phung]

some suggestions:

function oatmeal_fn(Oatmeal_h, evt, TOTAL) % i would remove TOTAL if you could, 
                                           % and instead replace it with the figure handle if it is possible, 
                                           %else, retrieve figure handle with 'gcf' (gets current figure)
  f = gcf; % your figure handle
  total = f.UserData % you should set the user data to be your TOTAL matrix outside of this function; 
                      % this line retrieves this information
                      
  ind = 5; %this is the index for oatmeal;
  total(ind) = total(ind)+ 1 % adds one to oatmeal
  f.UserData = total; %saves the matrix into User data, to be used by other buttons.
end

this is assuming you have 24 other callbacks.

[Andrew Lorick]

Can you explain user data? And what does f. do?

[Kevin Phung]

if you create a figure:

f = figure;

and then run f on the command line, you will see a list of properties associated with the figure. Position, units, callback functions, etc. This goes for every graphical user interface object as well (pushbuttons, listboxes, edit fields, etc).

There is a property called UserData, where you can use to store any sort of information you'd like, that can be retrieved anywhere within other callback functions. the dot notation:

f.Position

is the same as get()

get(f,'Position')

[Andrew Lorick]

So, outside of the callback fn I set:

TOTAL=get(f,'userdata);

function oatmeal_fn(Oatmeal_h, evt, f)
  
total=get(f,'userdata');
ind=5;        
total(ind)=total(ind)+1; %So here we are saying total(5) which is total(row 5)?
set(f,'userdata',total); 
  
endfunction

When I run this, I get an error: "binary operator '+' not implemented for 'cell' by 'scalar' operations"

I understand that 'userdata' is a cell array and not a matrix, so I tried using cell2mat:

function oatmeal_fn(Oatmeal_h, evt, f)
  
total=get(f,'userdata');
cell2mat(total);
ind=5;
total(ind)=total(ind)+1;
set(f,'userdata',total); 
  
endfunction

Unfortunately, I get the same error.

[Kevin Phung]

no, whichever line you created your figure along with its handle, you should be setting

f.UserData = zeros(1,numel(ING)) %this will represent your total. where f is your figure handle

the variable 'total' is only within the scope of each callback.

function oatmeal_fn(Oatmeal_h, evt, f)
  
total=get(f,'userdata');
ind=5;        
total(ind)=total(ind)+1; %So here we are saying total(5) which is total(row 5)?
set(f,'userdata',total); 
  
end

if for the sake of less lines of code but less clarity:

function oatmeal_fn(Oatmeal_h, evt, f)
ind=5;        
f.UserData(ind) = T.UserData(ind) + 1;
end