MATLAB: Issue with GUI editbox callback

guisave

I need to save the text entered into two edit boxes so that I can concatenate them with other strings to create the name of a desired file. Example code below:

function subject_editbox_Callback(hObject, eventdata, handles)

% hObject handle to subject_editbox (see GCBO)

% eventdata reserved – to be defined in a future version of MATLAB

% handles structure with handles and user data (see GUIDATA)

input=get(hObject,'String');

display(input)

sub=input;

function trial_editbox_Callback(hObject, eventdata, handles)

% hObject handle to trial_editbox (see GCBO)

% eventdata reserved – to be defined in a future version of MATLAB

% handles structure with handles and user data (see GUIDATA)

input = get(hObject,'String');

display(input)

trial = num2str(input);

% — Executes on button press in createfile.

function createfile_Callback(hObject, eventdata, handles)

% hObject handle to createfile (see GCBO)

% eventdata reserved – to be defined in a future version of MATLAB

% handles structure with handles and user data (see GUIDATA)

Note: variables "displacement and "file_type" specified in individual button group SelectionChangeFcn callbacks

filed=strcat(sub,displacement);

filedesi=strcat(filed,trial);

filedesired=strcat(filedesi, file_type)

display(filedesired)

When I click on the pushbutton, it says:

"Undefined function or variable 'sub'.

Error in Vicon_GUI_Zeke>createfile_Callback (line 225) filed=strcat(sub,displacement);

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

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

Error in @(hObject,eventdata)Vicon_GUI_Zeke('createfile_Callback',hObject,eventdata,guidata(hObject))

Error while evaluating uicontrol Callback"

Best Answer

You need to save your variables (i.e. the strings from the editboxes) as fields of the structure handles. So correct your functions as the one below:

function subject_editbox_Callback(hObject, eventdata, handles)
input=get(hObject,'String');  
display(input)  
handles.sub=input;
guidata(hObject, handles);

Only then you can concatenate handles.sub with handles.displacement

Related Solutions

MATLAB: Project help, I need to submit the project a gui tommorow but i keep on getting errors

You have a uicontrol with tag 'mass1', so GUIDE automatically creates handles.mass1 as the handle of that uicontrol .

If you happen to go through mass1_Callback then you replace handles.mass1 with the str2double() of the string that was stored there, leaving handles.mass1 as a numeric value that can no longer be used to reference the uicontrol. For example, reset_Callback would fail as you would try to set() the String property of the double that you had stored in handles.mass1 . But we can prove that you did not go through that callback, because that callback contains

if isnan(mass)

and mass is undefined in that context so you would have failed in that callback.

If you do not happen to go through mass1_Callback (or you crashed in that callback) then in calculate_Callback then the first thing you do is

hoop=handles.mass1*(handles.radiusb.^2);

which would be an attempt to multiply the handle of the uicontrol for mass1 by something. That is going to fail.

Morals of the story:

do not store values into the handles structure using the same name as one of your graphics objects
you need to plan for the case where the flow of control is not what you expect -- so if you are using mass1_Callback to store the numeric equivalent of the mass1 uicontrol string into the handles structure, then you need to have stored the default numeric value for that into handles (in case the user did not happen to go through that callback) or you need to disable all callbacks that rely on the numeric mass1 value until you have gone through the mass1_Callback
for simple numeric values like you have for your variables, a more typical style would be to just validate in the edit callback like mass1_Callback, verifying that the string represents a number within bounds but not storing the numeric value inside the handles structure. Then when you need the numeric value in your other callbacks, fetch the string and convert it. This ensures synchronization (the stored numeric value cannot disagree with the string if there is no stored numeric value), and keeps you from having to update the handles structure all the time -- the fewer items you have stored in the handles structure, the more efficient using the handles structure is. This is not the only possible way to create a GUI, but it does have some advantages.

MATLAB: Help for batch selection in graphical window

There is information missing from this, such as what the object type and Style for CercaFile is, and the certainty that CercaFile_Callback is the callback for that object.

If we presume a listbox and presume that CercaFile_Callback is indeed its callback, then edit CercaFile_Callback so that instead of invoking guide() or open() on the chosen file, it records the file name in which-ever location is convenient for you.

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