Attempt to reference field of non-structure array

I am using GUIDE to create a nifty tool. Originally I would open the ".fig" file in GUIDE, as you right-click it. Then run the program from there. Today I decided to 'OPEN' it directly when I right-click the ".fig" file. Here is the error:

??? Attempt to reference field of non-structure array.

Error in ==> Cable_Sizing_Rev3>choose_resistance_data_source_popup_Callback at 1569
relevant_handles = [ handles.resistivity_edit, handles.resistivity_text, handles.unit_resistivity_text, ...

Error in ==> gui_mainfcn at 96
        feval(varargin{:});

Error in ==> Cable_Sizing_Rev3 at 53
    gui_mainfcn(gui_State, varargin{:});

Error in ==>
@(hObject,eventdata)Cable_Sizing_Rev3('choose_resistance_data_source_popup_Callback',hObject,eventdata,guidata(hObject))

??? Error while evaluating uicontrol Callback

I have checked other soluctions and it didn't quite help solve the problem.

Answer 1

[Image Analyst]

You are referencing three fields of handles: resistivity_edit, resistivity_text, and unit_resistivity_text. handles does not have at least one of those fields . Put handles with no semicolon right before you call the line:

handles
relevant_handles = [ handles.resistivity_edit, ............

That will cause all the fields of handles to be sent to the command window so you can determine which one field is missing.

EDIT: On second thought, you can't run the fig file from the current folder panel like you tried. You have to either type F5 or click the green triangle if you're in the editor, or click the green triangle in GUIDE. That's why handles is undefined.

[tuyen]

Thanks for your time to answer this. I will compile this into .exe file very soon.

Answer 2

[Matt J]

Doesn't sound like a problem. The initial way you were running the GUI is the right one. You can also run the mfile that GUIDE produces to launch the GUI.

[tuyen]

Do you think that by opening ".fig" file directly, doesn't read (if thats the correct term) the OpeningFcn section of the m-file? Unless I misunderstood the difference of how MatLab initializes the run process of GUI. Thanks

[Matt J]

Yes. The primary execution functionality of the GUI is managed by the mfile, not the .fig file, so launching the latter doesn't do much. When you launch the GUI from the GUIDE toolbar, it is basically invoking the mfile as well.

[tuyen]

Very good, thanks very much for your input and support, I really am. I am still curious to why my other GUI's did not have the same error of "Attempt to reference field of non-structure array." I will dig into this when there is time, even though opening it directly have the errors, while it still functions by opening through Mfile or GUIDE.

[Matt J]

Are you sure the above errors are generated immediately just by opening the .fig? Or, is it possible that you opened the .fig and then started pressing buttons and uicontrols? I can imagine the later triggering the errors you see. Your callbacks would then be launched without the gui's data first being properly initialized by your OpeningFcn.

[tuyen]

That is correct, it does not show the error immediately, only when I make this one particular selection. Does make sense to have it run (green play button) from the Mfile or GUI figure first. Thanks J.

[tuyen]

Wow, I can't accept TWO answers?! I am sorry Matt J., you definitely deserve a reputation as well.