plot excel file from listbox selection using GUIDE GUI

Hi,

I am trying to create a GUI using guide that has 1) a push button that loads multiple files into a 2) listbox, from which 3) you can select one or (ideally multiple) files to display on a plot (see screencap).

currently this code populates the listbox using the pushbutton (successful)

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

%GOALS: get file, set popup menus to reflect column names, update axes when
%popup selection is updated

% LOAD MULTIPLE FILES
[filename,pathname] = uigetfile('*.xlsx', 'Chose files to load:','MultiSelect','on');
nfiles = length(filename);
for k = 1:nfiles
  file = fullfile(filename,pathname(k));
end

%update master copy of handles information
guidata(hObject, handles);

% update listbox with the result from above 
set(handles.listbox2, 'String', fullfile(filename,pathname));
    
%set popup menus and update axes callbacks for dropdowns and radiobuttons 
setPopupmenuString(handles.popupmenuX,eventdata,handles)
setPopupmenuString(handles.popupmenuY,eventdata,handles)
set(handles.popupmenuX, 'callback', 'HarkerGuiMulti(''updateAxes'',gcbo, [], guidata(gcbo))');
set(handles.popupmenuY, 'callback', 'HarkerGuiMulti(''updateAxes'',gcbo, [], guidata(gcbo))');

but this code does not work for reading an excel file in when it is selected in the listbox,

% --- Executes on selection change in listbox2.
function listbox2_Callback(hObject, eventdata, handles)
% hObject    handle to listbox2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: contents = cellstr(get(hObject,'String')) returns listbox2 contents as cell array
%        contents{get(hObject,'Value')} returns selected item from listbox2

%SELECT FILE FROM LISTBOX 
% get(handles.figure1,'SelectionType')
% if strcmp(get(handles.figure1,'SelectionType'),'open')
    index_selected = get(handles.listbox2,'Value');
    file_list = get(handles.listbox2,'string');
    selected = file_list{index_selected};
    handles.data = xlsread(fullfile(selected));
    

the above code gives me the following error

    Error using xlsread (line 139)
XLSREAD unable to open file
'HAB20_liquid.xlsx\C:\Users\emily\Documents\UW
Madison Coursework\GEO537 Quant Methods
Matlab\project\test_data\'.
File
'HAB20_liquid.xlsx\C:\Users\emily\Documents\UW
Madison Coursework\GEO537 Quant Methods
Matlab\project\test_data\' not found.

Error in HarkerGuiMulti>listbox2_Callback (line
200)
    handles.data = xlsread(fullfile(selected));

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

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

Error in
matlab.graphics.internal.figfile.FigFile/read>@(hObject,eventdata)HarkerGuiMulti('listbox2_Callback',hObject,eventdata,guidata(hObject)) 
Error while evaluating UIControl Callback.

any help is much appreciated!

Answer 1

[Cris LaPierre]

You do populate the listbox, but your filenames are messed up (the filename comes first followed by the path name)

'HAB20_liquid.xlsx\C:\Users\emily\Documents\UW Madison Coursework\GEO537 Quant Methods Matlab\project\test_data\'

If you read the error message, you can see that you have placed the path information in the wrong place.

    Error using xlsread (line 139)
XLSREAD unable to open file
'HAB20_liquid.xlsx\C:\Users\emily\Documents\UW Madison Coursework\GEO537 Quant Methods Matlab\project\test_data\'

Your pushbutton code contains the following code:

for k = 1:nfiles
  file = fullfile(filename,pathname(k));
end

Note that fullfile puts things together in the order you place them, while uigetfile returns filename first, then pathname.

fullfile('part1','part2','part3')

ans =
    'part1\part2\part3'

[Emily Mixon]

Thanks--that did help, but I think there's still something off about how I am reading them using xlsread? I read them and then assign them handles.data, but then wherever I have data=handles.data, it tells me that 'data' is undefined...

    % --- Executes on selection change in listbox2.
function listbox2_Callback(hObject, eventdata, handles)
% hObject    handle to listbox2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: contents = cellstr(get(hObject,'String')) returns listbox2 contents as cell array
%        contents{get(hObject,'Value')} returns selected item from listbox2index_selected = get(handles.listbox2,'Value');
    file_list = get(handles.listbox2,'string');
    selected = file_list{index_selected};
    handles.data = xlsread(fullfile(selected));
    
 % Set popup menu string to be column names for a given file 
function setPopupmenuString(hObject,eventdata,handles)

data=handles.data;
[numbers,colNames]=xlsread(fullfile(selected));
set(hObject,'string',colNames);

[Cris LaPierre]

Ah yes. One more little trick to show you about guide. Remember, callbacks are functions, and variables created inside a function do not exist once the funcion has terminated (unless they are passed out). Each callback has handles as an input, but no outputs...

Guide has a little trick - saving the handles structure to the figure window itself. Yeah, don't worry about the details. What you need to do is, at the bottom of your function, if you've modified the handles structure, store the updated handles structure to the figure using guidata.

function listbox2_Callback(hObject, eventdata, handles)
...
    file_list = get(handles.listbox2,'string');
    selected = file_list{index_selected};
    handles.data = xlsread(fullfile(selected));
    
    % Update handles structure
    guidata(hObject, handles);