Question about accessing data in GUIDE GUI

So, I recently made a few MATLAB functions through which I can read data, then perform some operations on them (like calculate distances between points, etc).

I can do this fine with a number of functions, but once I tried to make a GUI to make my life a bit easier things got more difficult.

Basically, every time I manipulate data and want to plot the data using a button, I keep on getting a error message saying the data doesn't exist, or rather, it cannot access it. I probably need to nest the data in some way, but I am relatively new to this kind of thing and can really use some advice. I looked at the literature and found this: http://www.mathworks.com/help/techdoc/creating_guis/f13-998449.html#f13-1000157, so I will take a look in the meantime.

Thanks for your help, this is a relatively new field of MATLAB programming for me.

Answer 1

[Titus Edelhofer]

Hi Brian,

using nested functions (the link you provided) is in my opinion and godd way, but only if you write the GUI by hand. If you use guide to design your gui, which I would strongly suggest at the beginning, then better use either application data or guidata (the next two paragraphs below your link).

In short: when you read the data, use the function setappdata to store the data, and in another callback use getappdata to access it again.

Titus

[Brian]

Hello, thanks for answering:

I tried using guidata and I think its almost working, minus one problem.

I can store data, I believe, using:

   data1 = guidata(hObject) %Number corresponds to data set N

However, once I try to retrieve the data using gcbo, it mentions a data type mismatch, possibly because I need to convert the data first? Another answerer suggested I need to convert the cells to data?

The (rough) code I used once I hit my regraph function button was:

   data1 = gcbo; data2 = gcbo;
   plot(data1, data2);

[Titus Edelhofer]

Nearly: to store and read data to the following: suppose your data to be stored is a variable called data1:

% store data1:
handles.data1 = data1;
guidata(hObject, handles);

% read data1 (somewhere else, another callback e.g.):
handles = guidata(hObject);
data1 = handles.data1;

Titus

[Brian]

Thanks! This worked out perfectly, I managed to input my data without any problems.

Answer 2

[Azzi Abdelmalek]

a simple way to manipulate data is to store them in any of your object using userdata like below:

       set(handles.yourobject,'Userdata',data) % data is your data, 
 % to get your data use
       data=get(handles.yourobject,'Userdata) ; 
% don't forget to do some conversion because data is a cell.

[Brian]

Thanks, I will try this later.

If I want to store multiple types of data, and then access those different types for plotting (in my case, I have a set of points and connections) can I store the points and connections in two different userdata cells?

So, maybe something like:

      set(handles.yourobject,'Userdata1',data1) % data is your data, 
   % to get your data use
      data=get(handles.yourobject,'Userdata1') ; 
   % don't forget to do some conversion because data is a cell.

For dataset 1, and then userdata2 for dataset two? Or something along these lines?