Saving handles in callback function of button in dialog box opened by other button in GUI

Good day all,

First of all, this is the first time I'm asking anything here, so I hope I'm making this as clear as I can. I also know there are a lot of different topics about saving the handles inside a GUI, and I've read a lot of them, but I still can't find and answer to this problem.

I have made a GUI with guide, and I have added an "option" button. This button opens a dialog box with a few uicontrols (I couldn't find a way to use guide for the dialog box as well, so I'm just coding that the hard way), most importantly 2 listboxes and 2 pushbuttons. The first listbox consists of X names, while the second box is empty to start out with. The buttons have callback function that takes the selected name, removes it from that list, and adds it to the other list. It should also save this to the handles structure of the GUI so that if you re-open the options dialog box after closing the names are still in the correct listboxes.

This doesn't work as intended, and I believe it is due to how I save the handles structures. The important parts of the code look something like this:

function varargout = MFI(varargin)
% MFI MATLAB code for MFI.fig
% Just all the standard stuff that guide automatically makes

% --- Executes on button press in adaptOptionsButton.
function adaptOptionsButton_Callback(hObject, eventdata, handles)

d = dialog('Position',[300 300 700 700],'Name','Select One');

handles.listbox1 = uicontrol('Parent',d,...
    'Style','listbox', ...
    'Tag', 'listbox1', ...
    'Position',[75 70 100 100],...
    'String', handles.parameterNames(handles.constantParameterIndex)); 

handles.listbox2 = uicontrol('Parent',d,...
    'Style', 'listbox', ...
    'Tag', 'listbox2', ...
    'Position',[245 70 100 100],...
    'String', handles.parameterNames(handles.fitParameterIndex));

pushbut1 = uicontrol('Parent', d, ...
    'Style', 'pushbutton', ...
    'Position', [195 140 30 30], ...
    'String', '>', ...
    'Callback', {@constantToFitButton_callback, handles});

function constantToFitButton_callback(hObject, eventdata, handles)

selectedParNum = handles.listbox1.Value;

temp_str = handles.constantParameterNames(selectedParNum);
temp_par_num = find(strcmp(handles.parameterNames, temp_str));
% Do some things that are not important for this problem, mostly just things like:
% handles.something = XYZ;
% handles.somethingelse = ABC;

guidata(handles.figure1, handles);

What happens now is that when I click the button, the dialog box appears, and the two lists are filled with the names as they are stored in the handles structure. When I select a parameter from the left list and click the "constantToFitButton" the parameter disappears from list 1, and appears in list 2, as intended. However, when I select another parameter and press the same button, this parameter gets added to the second list, but the previous selected parameter 'magically' appears back in the first list. When I close the dialog box, and re-open it, the last change I made was stored correctly and is displayed in the right listbox.

I sort of know what is going on. I believe that the handles are different in each function and that I only store them to the main GUI, so that when I press the button again, the old not-updated handles are used, and that's where everything goes amiss. I have no clue how to solve this, I have tried so many things, with so many different ways of saving handles between different functions, and with most things I do it works just fine, but with this dialog box I just keep encountering problems...

I've already tried adding "guidata(hObject, handles)" (and other variations) to the "adaptOptionsButton_Callback", but that didn't do anything.

If somebody could tell me what I'm doing wrong, I would be very grateful!

Answer 1

[Adam]

Never pass handles around yourself to a callback function that you create a function handle to. Instead pass the handle of the GUI itself and use

handles = guidata( hGUI );

where you need to access the handles and

guidata( hGUI, handles )

to write an updated version of handles back to the GUI.

[Pascal van Beek]

Hi Adam, thanks for your answer! Do you mean hObject? Because I've tried that, but hObject seems to be empty in the last function, so I wasn't able to use that. And hGUI is an undefined function or variable when I try to use that.

[Adam]

If you haven't changed the tag then it should be:

handles.figure1

though I would always recommend to change the tag of the figure in GUIDE.

I just call it hGUI as a placeholder variable in the function where you would pass the above in rather than handles.

[Pascal van Beek]

I've tried using that, but that doesn't work quite as I expect it. I managed to get it to work, partly with your help, although I don't think it is the "correct" way to make it work. I now have this:

function bla_Callback(hObject, eventData, handles)

handles = guidata(gcf);

d = dialog(....)
listbox1 = uicontrol(...)
listbox2 = uicontrol(...)
pushbut1 = uicontrol(..., ...
'Callback', @burpButton_callback);

guidata(gcf, handles);

function burpButton_callback(hObject, eventdata, handles)

handles = guidata(gcf);

% Some random code
handles.thingIwantToStore = 42;
% More random code

guidata(gcf, handles);
guidata(handles.figure1, handles);

If I use handles.figure1 instead of gcf, then I get an empty handles structure when calling guidata(handles.figure1) inside burpButton_callback, so I needed to use gcf. But if I only used guidata(gcf, handles) within burpButton_callback, then the handles of my main GUI wouldn't be updated.

Now the guidata(gcf, handles) inside burpButton makes sure that all the list objects actually show up, and the guidata(handles.figure1, handles) makes sure that the objects actually get stored... So this cannot be the most elegant way of doing it, but at least it works.

[Adam]

Why are you still passing handles into this callback though? It doesn't do harm because you overwrite whatever it is you pass in there straight away anyway, but it adds confusion.

handles.figure1 should not have empty handles, assuming figure1 is actually the correct figure (well, if it is any GUIDE figure)