GUI listbox: problem to load/initialize the list from a data file?

Hello Everybody,

I would be very grateful to get your help... I'm trying to create (from an empty listbox UI) a list coming from an ascii file. It works ok, except that I have to click on the first empty line of the listbox UI to make appear my "new" string list in the listbox. I would like to have it appears straight after the data file opening.

Note that the line : "data=ImportTxtData_Function(filename)" is a function importing/storing a structure containing the "data.datasetNameFields" which is a cell containing the list of strings (to be displayed in the listbox UI).

I attached the main "simple_ListBox_Test_V2.m", the "ImportTxtData_Function.m" and an the txt file from where the data are imported...

Here is the main GUI code:

function simple_ListBox_Test()
% Click "Open file" to download the list from the ascii file, then
% the list of strings is supposed to appear in the listbox UI
clc
%clear all; close all;

     % Create and then hide the GUI as it is being constructed. Position
     % give the position and size of the GUI interface
     hFig = figure('Visible','off','Position',[560,800,300,600]);%, 'ToolBar', 'none');
    % create structure of handles
     myhandles = guihandles(hFig); % contains at this stage only the initial handles of the figure
    % Save the structure
     guidata(hFig,myhandles) ;
    %%%Create a new toolbar with factory icons
    hFig.ToolBar = 'none'; %%hide the standard toolbar

hNewToolbar = uitoolbar ('parent',hFig) ;
hButton=uitoolfactory(hNewToolbar,'Standard.EditPlot');
hButton=uitoolfactory(hNewToolbar,'Exploration.Rotate');
hButton=uitoolfactory(hNewToolbar,'Annotation.InsertColorbar');
set(hButton,'Separator','on');
hButton=uitoolfactory(hNewToolbar,'Exploration.ZoomIn');
hButton=uitoolfactory(hNewToolbar,'Exploration.ZoomOut');
set(hButton,'Separator','on');

% Assign the GUI a name to appear in the window title.
   hFig.Name = 'Simple GUI';
% Move the GUI to the center of the screen.
   movegui(hFig,'center')
% Make the GUI visible.
   hFig.Visible = 'on';

   %%%%%%%%%%%%%%%%%%%%%%%%%%%%
   % Construct the components.
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%
     OpenTifFile = uicontrol(hFig, 'Style','pushbutton',...
            'String','Open File',...
            'Position',[100,550,70,25],...
            'Callback',@OpenTifFilebutton_Callback);

     hVariableListBox = uicontrol(hFig, 'Style','listbox',...
             'String',{[]},...
             'Position',[50,50,200,450],...
             'Callback',@VariableListBox_menu_Callback);

      %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     % Callbacks for simple_gui.
     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

   function OpenTifFilebutton_Callback(hObject, eventdata, handles)
       % GUI file opening
  disp('File selection in progress')
  [filename, pathname] = uigetfile('*.txt', 'Select a .txt file');
  if isequal(filename,0)
     disp('File selection cancelled')
     return
  else
     disp(['User selected ', fullfile(pathname, filename)])
     filename=strcat(pathname, '\',filename);
  end

fid = fopen(filename);
if fid==-1
   error(['File ' filename ' not found']);
end

data=ImportTxtData_Function(filename);

% Get the structure using guidata in the local function
     myhandles = guidata(gcbo);
% Add my data to the current handle structure
     myhandles.data=data;
% Save the change made to the structure, i.e. adding data struct in myhandles
     guidata(gcbo, myhandles) ;

   end

function VariableListBox_menu_Callback(hObject, eventdata, handles)

% Get the structure using guidata in the local function
    myhandles = guidata(gcbo);
    VariableList= myhandles.data.datasetNameFields(1:end);
% update the list box with the new selection
    set(hVariableListBox,'String', VariableList)
% Get the number of the item which is click in the listbox
    SelectedVariableNo = get(hVariableListBox, 'value')
% Store the string name of the selected variable
    SelectedVariableName= VariableList(SelectedVariableNo)

end

end

[Jan]

The indenting in the forum is poor. Are the callbacks embedded functions?

Answer 1

[Jan]

All you have to do is updating the strings as in VariableListBox_menu_Callback:

data=ImportTxtData_Function(filename);
VariableList = data.datasetNameFields;   % Without the unneeded "(1:end)"
set(hVariableListBox, 'String', VariableList);

Updating the string in the callback of the listbox is not useful. So remove the code there.

Notes:

1. Better: Prefer fullfile in every case:

disp(['User selected ', fullfile(pathname, filename)])
filename=strcat(pathname, '\',filename);

==>

filename = fullfile(pathname, filename);
disp(['User selected ', filename])

Do not insert filenames in the error message directly:

error(['File ' filename ' not found']);

This will have unexpected results, if the name contains a '%' or other control sequences. Safe:

error('File %s not found', filename);

"1:end" wastes time only:

VariableList = myhandles.data.datasetNameFields(1:end)

==>

VariableList = myhandles.data.datasetNameFields;