Handles not getting updated from pushbutton using GUIDE

Question

Pratik Chachad 2021-8-10

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/895852-handles-not-getting-updated-from-pushbutton-using-guide

评论： Pratik Chachad 2021-8-10

Hello Everyone,

For my own understanding, I am trying to create a simple counter GUI with 2 pushbuttons namely 'Start counting' and 'Stop counting'

Start counting - Starts the counter

Stop counting - Stops the counter

I am having troubles to Stop the running counter using the Stop pushbutton. For some reason the handles.stop which gets set to 1 in the StopCounter_Callback does not reflect in the StartCounter_Callback.

Here is the piece of code.

Any help will be much appreciated. Thanks in advance.

function StartCounter_Callback(hObject, eventdata, handles)

counter = 0;

handles.start = 1;

while (1)

guidata(hObject, handles);

if (handles.stop == 0)

counter = counter + 1;

myString = sprintf('Value is %d', counter);

set(handles.text1, 'String', myString);

drawnow;

pause(0.1);

else

% Reset the Start & Stop button

handles.stop = 0;

handles.start = 0;

return;

end

% --- Executes on button press in StopCounter.

function StopCounter_Callback(hObject, eventdata, handles)

if(handles.start == 1)

handles.stop = 1;

end

guidata(hObject, handles);

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Answer 1

Rik 2021-8-10

1
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/895852-handles-not-getting-updated-from-pushbutton-using-guide#answer_764397

Your looping function doesn't store the modified handle struct.

guidata(hObject, handles);
%put this before your return statement

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Pratik Chachad 2021-8-10

在 MATLAB Online 中打开

Hello @Rik Thanks for your response. I think I found the answer. The issue was that I was not retriving the updated elements from handles structure.

"handles = guidata(handles.figure1);"

My updated code is here. Everything works now as expected. Thanks.

function StartCounter_Callback(hObject, eventdata, handles)
% Run the loop once, if start is already running do nothing
if(handles.start == 0)
    handles.start = 1;
    %save the data
    guidata(hObject, handles);
    
    counter = 0;
   
    while (handles.start)
    
        handles = guidata(handles.figure1);
    
        if (handles.stop == 0)
            counter = counter + 1;
            myString = sprintf('Value is %d', counter);
            set(handles.text1, 'String', myString);
            drawnow;
        else 
            % Reset the Start & Stop button
            handles.stop = 0;
            handles.start = 0;
        
            %save the data
            guidata(hObject, handles);
        end
    end
end
function StopCounter_Callback(hObject, eventdata, handles)
% hObject    handle to StopCounter (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
if(handles.start == 1)
    handles.stop = 1;
end
guidata(hObject, handles);