GUI stops working after pushbutton function has completed

I have created a GUI (called GNgui) using GUIDE that runs a function when a 'Scan' button is pressed. It disables all the other buttons/fields in the GUI until it stops running, where it enables all the buttons again.

After the function runs (successfully), I'd like to be able to hit the 'Scan' button again to repeat the process, but every time I do, I get the following error message:

Undefined function 'GNgui' for input arguments of type 'struct'.

 Error in
@(hObject,eventdata)GNgui('fileName_Callback',hObject,eventdata,guidata(hObject))

 Error while evaluating uicontrol Callback

This isn't mutually exclusive to that push button either. When I try to press any other button (or even try to close the GUI window), I get a very similar error.

Any ideas? I've attached my .m file.

PS: I realise the code is a little messy, I'm trying to update and improve on some code someone else wrote.

[Image Analyst]

We'd need the .fig file also.

[Oscar Knights]

Apologies... I've attached the .fig file.

Answer 1

[Meade]

I believe that the call back is written incorrectly. Your anonymous function syntax is telling the callback function that the second input is "evt" which is a struct by default. However, you're passing "hObj" as the second input.

try this:

@(hObject,eventdata)GNgui(hObject,eventdata,guidata(hObject))

[Oscar Knights]

Sorry, I'm new to GUI's. Which callback should I replace?

[Meade]

Remove 'fileName_Callback' and then put your debug stop inside the callback function (the little red dot to the left of the line).

What does it report?

[Oscar Knights]

Okay, so I removed the 'filename_callback' from the 'Filename' textbox callback function, and ran the code but the problem persists.

When I placed the debug stop in the 'fileName' function, it did not display anything and allowed me to 'continue'.

I don't think it's a problem with the fileName function though, since after hitting the 'Scan' button, and allowing it to complete its process, I can't then click on any of the other buttons (or even close the window). I got this error message when trying to run the scan again...

 Undefined function or variable 'hObject'.

 Error while evaluating uicontrol Callback

 Undefined function 'GNgui' for input arguments of type 'struct'.

 Error in
 @(hObject,eventdata)GNgui('scanButton_Callback',hObject,eventdata,guidata(hObject))

 Error while evaluating uicontrol Callback

Thanks for your help so far.

[Meade]

Can you post the code for your 'scan button'?

[Oscar Knights]

% --- Executes on button press in scanButton.
function scanButton_Callback(hObject, eventdata, handles)
% hObject    handle to scanButton (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
set(handles.scanButton, 'String', 'Scanning...', 'Enable', 'Inactive')
set(handles.cancelButton, 'Enable', 'On', 'UserData', 'START')
set(handles.saveLocation, 'Enable', 'Off')
set(handles.modeSelect, 'Enable', 'Off')
set(handles.sampleNo, 'Enable', 'Off')
set(handles.changeSamplesBetween, 'Enable', 'Off')
set(handles.KeepBlankData, 'Enable', 'Off')
set(handles.stWave, 'Enable', 'Off')
set(handles.enWave, 'Enable', 'Off')
set(handles.stepValue, 'Enable', 'Off')
set(handles.width_of_sample, 'Enable', 'Off')

 global KeepBlank

 NoSamples = str2double(get(handles.sampleNo,'String'));
 StartWave = str2double(get(handles.stWave,'String'));
 EndWave   = str2double(get(handles.enWave,'String'));
 StepSize  = str2double(get(handles.stepValue,'String'));
 Mode      = get(handles.modeSelect,'Value');
 flag      = get(handles.changeSamplesBetween,'Value');
 maxVal    = get(handles.changeSamplesBetween,'Max');
 KeepBlank = get(handles.KeepBlankData, 'String');
 cancel    = get(handles.cancelButton, 'UserData');

 cTime = clock;

 h2 = warndlg({['No of Repeats: ' num2str(NoSamples)];['Start Wavelength: ' num2str(StartWave)];['End Wavelength: ' num2str(EndWave)];['Step Size: ' num2str(StepSize)]},'Scan Settings');
uiwait(h2);

    pauseVal = 0.01*StepSize;

    global GN

    %mode select
    if Mode == 2
        fprintf(GN,'CON');fscanf(GN);fscanf(GN); % select Concentration mode
        Type = 'C';
    else
        fprintf(GN,'ABS');fscanf(GN);fscanf(GN); % select Absorbance mode
        Type = 'ABS';
    end

    Wavelength = StartWave:StepSize:EndWave;
    si         = length(Wavelength);

    %    disp(KeepBlank)
    %while strcmp(cancel, 'START')
        if strcmp(KeepBlank, 'No')

            %cancel    = get(handles.cancelButton, 'UserData');

            h3 = warndlg('Please Insert Blank, then click OK');
            uiwait(h3);

 %           hw = waitbar(0,'Scanning Blank..');

            blank = NaN(si,1);

            for i = 1:si
                fprintf(GN,['GTO ' num2str(Wavelength(i))]);pause(pauseVal);fscanf(GN);fscanf(GN); 
                if i == 1
                    pause(2); %give extra time to change WaveLength at start of scan
                end
                fprintf(GN,'SND');pause(pauseVal);fscanf(GN);
                blank(i,1) = str2double(fscanf(GN));pause(pauseVal);fscanf(GN);
                %waitbar(i/si);

                axes(handles.axes5)
                cla
                rectangle('Position',[0,0,(round(1000*i/si))+1,20],'FaceColor','b'); 
                text(480,10,['Scanning Blank...', num2str(round(100*i/si)),'%'], 'FontSize', 16);
                pause(0.01)          

              axes(handles.axes1)

              plot(Wavelength,blank,'-','linewidth',2);
              title('Blank')
              xlabel('Wavelength (nm)');ylabel(Type);
              grid on

                 cancel = get(handles.cancelButton, 'UserData');
                    if strcmp(cancel, 'STOP')
                       error('Operation Aborted!')
                    end
            end

            %close(hw)

        elseif strcmp(KeepBlank, 'Yes') && exist('blank', 'var') == 0

            h3 = warndlg('Please Insert Blank, then click OK');
            uiwait(h3);

            %cancel    = get(handles.cancelButton, 'UserData');
            %hw = waitbar(0,'Scanning Blank..');

            blank = NaN(si,1);

            for i = 1:si
                fprintf(GN,['GTO ' num2str(Wavelength(i))]);pause(pauseVal);fscanf(GN);fscanf(GN); 
                if i == 1
                    pause(2); %give extra time to change WaveLength at start of scan
                end
                fprintf(GN,'SND');pause(pauseVal);fscanf(GN);
                blank(i,1) = str2double(fscanf(GN));pause(pauseVal);fscanf(GN);
                %waitbar(i/si);

                axes(handles.axes5)
                cla
                rectangle('Position',[0,0,(round(1000*i/si))+1,20],'FaceColor','b'); 
                text(480,10,['Scanning Blank...', num2str(round(100*i/si)),'%'], 'FontSize', 16);
                pause(0.01)       

              axes(handles.axes1)

              plot(Wavelength,blank,'-','linewidth',2);
              title('Blank')
              xlabel('Wavelength (nm)');ylabel(Type);
              grid on

             cancel = get(handles.cancelButton, 'UserData');
                if strcmp(cancel, 'STOP')
                   error('Operation Aborted!')
                end
            end

            %close(hw) 
        end

        sample = NaN(si,NoSamples);
        VAL    = NaN(si,NoSamples);
        Abs    = NaN(si,NoSamples);

        %cancel    = get(handles.cancelButton, 'UserData');

        for j = 1:NoSamples

            if j == 1    
            h4 = warndlg('Please Insert Sample, then press enter');
            uiwait(h4)
            elseif flag == maxVal
            h4 = warndlg('Please Insert Next Sample, then press enter');
            uiwait(h4)
    %         else
            end

            %hw = waitbar(0,['Scanning Sample number ' num2str(j) ' out of ' num2str(NoSamples) '.']);

            for i = 1:si
                fprintf(GN,['GTO ' num2str(Wavelength(i))]);pause(pauseVal);fscanf(GN);fscanf(GN);

                if i == 1
                    pause(2); %give extra time to change WaveLength at start of scan
                end
                fprintf(GN,'SND');pause(pauseVal);fscanf(GN);
                sample(i,j) = str2double(fscanf(GN));pause(pauseVal);fscanf(GN);
                %waitbar(i/si);
                VAL(i,j) = sample(i,j) - blank(i,1);

                axes(handles.axes5)
                cla
                rectangle('Position',[0,0,(round(1000*i/si))+1,20],'FaceColor','b'); 
                text(480,10,['Scanning Sample Number ', num2str(j), '/', num2str(NoSamples), '...', num2str(round(100*i/si)),'%'], 'FontSize', 14);
                %title(['Scanning Sample Number ', num2str(j), '/', num2str(NoSamples)])
                pause(0.01)       

    %              figure(2);
    %              plot(Wavelength,VAL,'.','linewidth',2);
    %              xlabel('Wavelength (nm)');ylabel(Type);  
                 axes(handles.axes2)

                 plot(Wavelength,sample,'-r','linewidth',2);
                 title('Sample')
                 xlabel('Wavelength (nm)');ylabel(Type);
                 grid on

                 axes(handles.axes3)

                 plot(Wavelength,VAL,'-','linewidth',2);
                 title(Type)
                 xlabel('Wavelength (nm)');ylabel(Type);
                 grid on

                 if strcmp(Type, 'ABS')
                     ww=str2double(get(handles.width_of_sample,'String'));
                     Abs(i,j)=VAL(i,j)/ww;

                     axes(handles.axes4)

                 plot(Wavelength,Abs,'-r','linewidth',2);
                 title('Absorption Coefficent')
                 xlabel('Wavelength (nm)');ylabel('Absorpation coefficent(mm^1)');
                 grid on

                 cancel = get(handles.cancelButton, 'UserData');
                    if strcmp(cancel, 'STOP')
                       error('Operation Aborted!')
                    end
                 end       
            end    
            %close(hw)
        end
    %     blankgvbblankblankcvblankvblankblankblankblankblank
      % save file

     name = get(handles.fileName,'String');
     DIR  = get(handles.saveLocation, 'UserData');

     filename = [name, '_', date];
     cd(DIR);

     save([filename,  '.mat'],'Wavelength','VAL','NoSamples','sample','blank','Abs');

 set(handles.scanButton, 'String', 'Scan', 'Enable', 'On')
 set(handles.cancelButton, 'Enable', 'Off', 'UserData', 'STOP')
 set(handles.saveLocation, 'Enable', 'On')
 set(handles.modeSelect, 'Enable', 'On')
 set(handles.sampleNo, 'Enable', 'On')
 set(handles.changeSamplesBetween, 'Enable', 'On')
 set(handles.KeepBlankData, 'Enable', 'On')
 set(handles.stWave, 'Enable', 'On')
 set(handles.enWave, 'Enable', 'On')
 set(handles.stepValue, 'Enable', 'On')
 set(handles.width_of_sample, 'Enable', 'On')

    %end

 if strcmp(KeepBlank, 'Yes')
    assignin('base', 'blank', blank)
 elseif strcmp(KeepBlank, 'No')
    clear blank
 end

 guidata(hObject, handles);
  end

[Meade]

Ok, so the problem seems to be that the 'handles' argument that is being passed to ALL your callbacks is empty.

I can't run the full gui since it's looking for some sort of COM connection, but you need to get all the handles for all the things you created in the GUIDE creator.

As a start, swap lines 41:45 with these

hFig = ancestor(hObject,'figure');
handles = guihandles(hFig);

% Choose default command line output for GNgui
handles.output = hObject;

% Update handles structure
guidata(hFig, handles);

This adds the structure 'handles' as guidata to the figure. Then, whenever a callback has the 'handles' arument, it should get this list of items.

[Oscar Knights]

I updated lines 41:45 with the code you provided but I still receive the following error:

 Undefined function 'GNgui' for input arguments of type 'struct'.

 Error in
 @(hObject,eventdata)GNgui('fileName_Callback',hObject,eventdata,guidata(hObject))

 Error while evaluating uicontrol Callback

 Undefined function 'GNgui' for input arguments of type 'struct'.

 Error in
@(hObject,eventdata)GNgui('scanButton_Callback',hObject,eventdata,guidata(hObject))

 Error while evaluating uicontrol Callback

When you say I need to 'get all the handles', what should I do with them? Again, sorry about being a bit of a novice when it comes to these things.