What caused GUI problem after Push Button is pressed and any recommended solution?

Hi. I have a GUI problem.

Here is code for the Push Button.

function runButton_Callback(hObject, eventdata, handles)
% selects graph1 as the current axes, so that
% Matlab knows where to plot the data
axes(handles.graph1)
range_find(pt, tau, fr, time_ti, gt, gr, freq, ...
 sigma, te, nf, loss, snro, range, out_option);
guidata(hObject, handles); % updates the handles

This is the code for the edit text for Pt

function ptEdit_Callback(hObject, eventdata, handles)
pt = str2num(get(hObject,'String'));
% checks to see if input is empty. if so, default input1_editText to 100
if (isempty(pt))
   set(hObject,'String','100')
   pt = str2num(get(hObject,'String'));
   msgbox('Please enter number only')
end
guidata(hObject, handles);

function ptEdit_CreateFcn(hObject, eventdata, handles)
% 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

When I run the GUI, I have the following error message ??? Undefined function or variable 'pt'.

Error in ==> mark_v1>runButton_Callback at 86 range_find(pt, tau, fr, time_ti, gt, gr, freq, ...

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

Error in ==> mark_v1 at 42 gui_mainfcn(gui_State, varargin{:});

Error in ==> @(hObject,eventdata)mark_v1('runButton_Callback',hObject,eventdata,guidata(hObject))

??? Error while evaluating uicontrol Callback

What can I do to overcome this problem? Any advice regarding this matter is highly appreciated. Thanks.

Answer 1

[Walter Roberson]

http://matlab.wikia.com/wiki/FAQ#How_can_I_share_data_between_callback_functions_in_my_GUI.3F

[Eric]

Thank you for your reply. From the explanation, I need to pass other variables (pt, tau, etc) to the runButton_Callback function. I decided to use the method 1: Using the handles structure.

I have tried it, but still it failed. Here is how I add the brand new variable on the handles structure.

function runButton_Callback(hObject, eventdata, handles)

% selects graph1 as the current axes, so that

% Matlab knows where to plot the data

axes(handles.graph1)

% Add a brand new variable on to the handles structure.

handles.pt = pt;

range_find(handles.pt, tau, fr, time_ti, gt, gr, freq, sigma, te, nf, loss,... snro, range, out_option);

guidata(hObject, handles); % updates the handles

The error message is

??? Undefined function or variable 'pt'.

Error in ==> mark_v1>runButton_Callback at 86

handles.pt = pt;

Error in ==> gui_mainfcn at 96

feval(varargin{:});

Error in ==> mark_v1 at 42

gui_mainfcn(gui_State, varargin{:});

Error in ==> @(hObject,eventdata)mark_v1('runButton_Callback',hObject,eventdata,guidata(hObject))

??? Error while evaluating uicontrol Callback

Can you guide me where should I add the brand new variables? Or perhaps this method is not effective? Any feedback is greatly appreciated. Thanks.

[Walter Roberson]

In which function *is* pt defined ? How is it defined there?

[Eric]

The function below is where the pt function is defined:

function runButton_Callback(hObject, eventdata, handles)

...

handles.pt = pt;

range_find(handles.pt, ...);

guidata(hObject, handles); % updates the handles

At which function callback should I declare pt variable?

Is it at

function ptEdit_Callback(hObject, eventdata, handles)

handles.pt = str2num(get(hObject,'String'));

...

guidata(hObject, handles);

or

function mark_v1_OpeningFcn(hObject, eventdata, handles, varargin)

% Choose default command line output for mark_v1

handles.pt;

guidata(hObject, handles);

Thanks

[Walter Roberson]

If you already assign to handles.pt in ptEdit_Callback then you do not need to assign pt to handles.pt in runButton_Callback -- but you do need to ensure that runButton_Callback is not called until after ptEdit_Callback, such as by setting runButton to 'Enable', 'off' at the beginning of the program, and only setting it to 'Enable' 'on' after ptEdit_Callback has checked the data and verified that the user-entered pt value is valid. (You should be checking for bad data in ptEdit_Callback; at minimum you should check that the str2num did not return [] or NaN. And it is better and much more secure to use str2double() than str2num