MATLAB: Handles problem

Question

Greetings.

I am trying to add a user defined variable to the "hObject" Handles via two radio buttons.

The radio button calling is here:

      set(handles.boardsize,'SelectionChangeFcn',@boardsize_SelectionChangeFcn);

The actual code that uses "setappdata is here:

function boardsize_SelectionChangeFcn(hObject, eventdata)
%retrieve GUI data, i.e. the handles structure
handles = guidata(hObject); 
switch get(eventdata.NewValue,'Tag')   % Get Tag of selected object
    case 'button5800'
      %execute this code when 5800 is selected
      setappdata(hObject,'boardtype',0)
      disp('this is working')
    case 'button9800'
      %execute this code when 9800 is selected
      setappdata(hObject,'boardtype',1)
      disp('this is working')
    otherwise    
        % Code for when there is no match.
end
%updates the handles structure
guidata(hObject, handles);

Then later on I try and get the add data within the main function

boardsize = getappdata(hObject,'boardtype')

But the board type variable is always empty "[]" Am I updating the wrong handles? This one has had me for a while. Thanks to all who look at it.

Answer 1

setappdata() and getappdata() do not take the handles structure as their first argument. They take the handle of a single graphics object, and they act with respect to that exact graphics object.

This differs from guidata() in that guidata climbs the hierarchy of the object given to it in order to find the ancestor figure and attaches the app data to that figure.

If you want to attach app data to your figure, find the figure first. For example,

setappdata(ancestor(hObject,'figure'),'boardtype',1);