How to create a minus counter

on the code above i created a add counter

function patient_Callback(hObject, eventdata, handles)
counter2 = get(hObject, 'UserData') + 1;
set(hObject, 'UserData', counter2);
set(handles.Impt, 'String', sprintf('Number of Patients currently: %d\n', counter2));

but the minus code doesnt work

function patients_Callback(hObject, eventdata, handles)
counter2 = get(hObject, 'UserData') - 1;
set(hObject, 'UserData', counter2);
set(handles.Impt, 'String', sprintf('Number of Patients currently: %d\n', counter2));
guidata(hObject , handles);

What should i change to the minus code.

[Walter Roberson]

What difficulty do you observe?

The guidata call is not necessary there but should not hurt.

[Kwan Zhao Jie]

the counter does not minus 1 when i press the button. The adding works fine.

[Walter Roberson]

Is it certain that the function is the callback for a uicontrol with tag 'patients'? If you put in a breakpoint is the function run at all?

[Kwan Zhao Jie]

Yes the tag i placed for the second button is patients. if i placed end at the end of the function, it doesn't run.

[Walter Roberson]

Have you tried using the debugger to see if the function is being called?

[Kwan Zhao Jie]

the function was not called. only the function for the addition was called. the function for addition is nurse and patient. Attached is the results.

[Walter Roberson]

Please attach your code and the fig file.

[Kwan Zhao Jie]

Attached is the Fig file and the code. Thank you in advance!

[Walter Roberson]

Impt_CreateFcn is missing.

For both patient_Callback and patients_Callback, you use

counter2 = get(hObject, 'UserData')

but notice that for patient_Callback, hObject is data attached to handles.patient, and for patients_Callback, hObject is data attached to handles.patients . You are not using the same data.

You should change patients_Callback to access handles.patient rather than hObject .

[Kwan Zhao Jie]

Thanks! It works now!

Answer 1

[Santosh Prasad Choudhury]

Please try to check the user data deafult value and how you validate them for value less than 0? please let me know