MATLAB: Problem with listbox in Matlab GUI.

guidelistboxMATLAB

Warning: single-selection listbox control requires that Value be an integer within String range Control will not be rendered until all of its parameter values are valid

I have 2 listbox. First listbox is show X coordinates and second one show the correspondind Y values for each X. eg. When I press X = 100 on the second listbox I see e.g Y = 100,101,102 ect. Sometimes when I press some values on Y listbox, and after that I change value on X listbox the Y listbox disappear and the error above shows.

Picture shows how it should work

Picture shows how it work when I press value higher than 100 on Y then when I press 442 X the Y listbox disappear.

I didn'y show the code because it's a lot of code and I think it's something wrong with listbox by itself. This is working properly. When I press 442 X it's working well but the error happens under specific conditions.

Any idea what might go wrong ?

Best Answer

Nothing is wrong with the listbox itself. There is something wrong in the callback for the X listbox, which you didn't want to show us. So you're either going to have to figure it out yourself of show us your code. In your callback for the X listbox, you're either

(A) doing something like loading the listbox for Y without the same number of entries it used to have like Y used to have 20 items in it and the selection was 18 and then you load it up with a cell array of 17 strings.

set(handles.listboxY, 'String', cellArrayOf17Strings);

Since the old (and current) value of 18 is more than the number of items now in the listbox (17), it won't be shown.

(B) You're setting a value for the listbox for Y that is greater than the number of strings in it. For example Y has 20 items and then in your X callback you do

set(handles.listboxY, 'Value', 21);

Since 21 is more than the number of items in the Y listbox (20), it won't be drawn.

Bottom line, look for where you reference handles.listboxY in your callback for listboxX.

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function upload_Callback(hObject, eventdata, handles)
    [filenamesCell, pathname] = uigetfile({'*.jpg'},'Select file(s)','MultiSelect');
    if ~isnumeric(filenamesCell)
      oldlist = cellstr( get(handles.listbox1, 'String') );
      set(handles.listbox1, 'String', [oldlist; fullfile(pathname, filenamesCell)]);
    end
function listbox1_Callback(hObject, eventdata, handles)
  choices = cellstr( get(hObject, 'String') );
  idx_chosen = get(hObject, 'Value');
  if ~isempty(idx_chosen)
    chosen_file = choices{idx_chosen);
    do something with chosen_file
  end

MATLAB: How to Add Element/Item to Listbox in Matlab GUI (push button, listbox)

Thomas - perhaps the condition

~strcmpi(Items_2, Item_1)

is never evaluating to true and so you never enter the body of the while loop. Part of the problem may be because Items_2 is always initialized to an empty cell array (is this intentional?) and is never set to what is currently in your list. Note that if I try the above, with

g = {};
strcmpi(g, 'hello')

then an empty array is returned...so I suspect that is the real problem. The condition is never satisfied. Try doing something like the following instead

function pushbutton2_Callback(hObject, eventdata, handles)
selectedString = handles.selectedItemStr; % assumed to be a string
listBox2Data = get(handles.listbox2,'String');
if isempty(listBox2Data) || ~any(strcmpi(listBox2Data, selectedString))
    listBox2Data = [selectedString, listBox2Data];
    set(handles.listbox2,'String',listBox2Data);
end

No need for a while loop in this case. Note that we use the call to any since the strcmpi may return an array of 0 or 1s for each element in the list box. any will return true if at least one of these elements is a one (indicating that the selected string is already in the list). If the call returns 0 (i.e. no element in list matches the selected string) then we add the item to the list.

Best Answer

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