How to get data from a variable number of Edit Text box in Matlab GUI ?

Hello everyone,

I am creating a GUI where a variable number of edit box is created based on the number entered from the user. Then I need to get the data written in each edit box. To do that I created a cycle for where N edit text boxes are generated using uicontrol.

for K=1:N
    edit(K) = uicontrol('Style', 'edit', 'String', '', 'Units', 'Pixels', 'Position', [175 ypos 110 30],'callback',@thickness); 
end

The problem is that I cannot get the values from each box because it gives me only the value written in the last box.

function pushbutton2_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
function []=thickness(hObject, eventdata, handles)

val=get(hObject,'string')
setappdata(0, 'value',val);

Do you have any suggestion how to save the data from all the boxes for example in a array? Thank you in advance

Answer 1

[Stephen23]

You will need to pass the array of handles edit to the callback/function where you want to access them all, and either:

• loop over the handles just like when creating the edit boxes, or
• simply get all values at once: get(edit,'String')

What you are doing now will only access one edit box, because when the callback thickness is called the input hObject only contains the handle for that one edit box that triggered the callback, not for all of the handles. Thus you need to pass all the handles yourself if you want to access them all at once.

[MDC]

Thank you Stephen for the fast reply. I tried to loop the handles but I got errors. Also If I simply use get(edit, 'string') it doesn't work. Can you please explain in more details how to get all the input please? Thank you very much

[Stephen23]

@MDC: please show the complete error message. This means all of the red text.

[MDC]

If I run this code (using get(edit, 'string'):

% --- Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

for K=1:2
    ypos=300-K*50;
 edit(K)= uicontrol('Style', 'edit', 'String', '', 'Units', 'Pixels', 'Position', [175 ypos 110 30],'callback',@thickness);
end

function edit2_Callback(hObject, eventdata, handles)
% hObject    handle to edit2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: get(hObject,'String') returns contents of edit2 as text
%        str2double(get(hObject,'String')) returns contents of edit2 as a double

% --- Executes during object creation, after setting all properties.
function edit2_CreateFcn(hObject, eventdata, handles)
% hObject    handle to edit2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% Hint: edit controls usually have a white background on Windows.
%       See ISPC and COMPUTER.
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
    set(hObject,'BackgroundColor','white');
end

% --- Executes on button press in pushbutton2.
function pushbutton2_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
 function []=thickness(hObject, eventdata, handles)

   val=get(edit,'value')
  setappdata(0, 'value',val);

% --- Executes on button press in pushbutton3.
function pushbutton3_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton3 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

a=getappdata(0,'value',val);

disp(a)

I got this error:

Error using get
Invalid handle

Error in tentativo>thickness (line 118)
 val=get(edit,'value')

Error while evaluating UIControl Callback

Error using get
Invalid handle

Error in tentativo>thickness (line 118)
 val=get(edit,'value')

Error while evaluating UIControl Callback

Undefined function or variable 'val'.

Error in tentativo>pushbutton3_Callback (line 129)
a=getappdata(0,'value',val);

Error in gui_mainfcn (line 95)
        feval(varargin{:});

Error in tentativo (line 42)
    gui_mainfcn(gui_State, varargin{:});

Error in @(hObject,eventdata)tentativo('pushbutton3_Callback',hObject,eventdata,guidata(hObject))

Error while evaluating UIControl Callback

[Stephen23]

@MDC: you forgot to pass the handles to the callback where you want to use them, just like I told you to do in my answer. Have a look at the callback thickness: where is edit defined? Answer: nowhere, thus the error. You will need to pass edit, e.g. using the handles structure:

for k = ...
    handles.edit(k) = ...
end
guidata(hObject,handles)

and in the callback where you want to use edit:

get(handles.edit,'String')

If you do not pass edit to the other callbacks, then it is not available in those other callbacks. You have to explicitly pass it in the code, because variables do not just magically jump from one callback to another (or from one workspace to another) (and nor should they).

[MDC]

You are completely right! Now everything works good! Thank you so much!

Answer 2

[Ahmed Anas]

Kindly send me the complete code for this, cant understand it well and have following error.

Error using My>thickness (line 135)
Not enough input arguments.
 
Error while evaluating UIControl Callback

Error using My>thickness (line 135)
Not enough input arguments.
 
Error while evaluating UIControl Callback