Best regards,

Cemil.

I created a GUI using guide with two sliders to adjust image window and level. When I use setappdata to my slider object a new figure is created when I started to use the slider. My image is displayed in the new figure instead of my current GUI figure. Any idea why this is happening. Your help is appreciated. Thanks.

Cemil

Positive feedback such as yours is very important for me when I have to explain to my family why I spend so much time on this website, for no apparent benefit…

The most difficult questions sometimes have very simple solutions, as in this case

hListener=handle.listener(handles.slider1,'ActionEvent',@updatetextbox);
setappdata(handles.slider1,'myListener',hListener);

You can do this in your main code – no need to use the Command Window. The reason it worked for you in the Command Window is that the handle.listener result was kept in the ans variable, so as long as ans was not changed the listener worked.

 
>> ni=untitled
 
ni =
 
  173.0035
 
>> handles=guidata(ni)
 
handles = 
 
    figure1: 173.0035
      text1: 1.0059
    slider1: 174.0031
     output: 173.0035
 
>> handle.listener(handles.slider1,'ActionEvent',@updatetextbox);
 
% *** Now try moving the slider ***
% YES, IT WORKS, we get to updatetextbox...
% So what arguments did updatetextbox get?
 
K>> varargin
 
varargin = 
 
    [1x1 uicontrol]    [1x1 handle.EventData]

Right, great news. So to do this, now I need a callback function of this form:

function updatetextbox(hObject, eventdata, handles)
handles=guidata(hObject);
slidval=get(handles.slider1,'Value');
set(handles.text1,'String',num2str(slidval));

And this finally works!!

Phew. Now, on to the “interesting” question. How can I “package” this up into the GUI itself (which was, as said, created by GUIDE, so I can’t just put the listener line after the creation of a uicontrol object. Using a script, which launches the GUI, then contains the above commands in chronographical order?

In fact, question no. 2:
I chose GUIDE because the fact of not having to set uicontrol object positions and sizes by coding but graphically is very easy and fast for me. Was that silly, and is that the reason for all the above suffering? (i.e. once one needs something past very basic funtionality – e.g. continuous slider callback – GUIDE is NOT the way to go?

In case there WAS anyone who followed through my “troubleshooting”, thanks, any further advice for a noob like me highly welcome.

Cheers,
Janos
Last bit of info:
I based this on the function untitled.m (and the associated saved untitled.fig) from here:
http://www.mathworks.com/support/solutions/en/data/1-3SR0YI/index.html?product=ML&solution=1-3SR0YI

Which is supposed to be a solution for exactly this problem. On its own, it did not work, and that is when I tried implementing your solutions (though it is supposed to be what I am looking for, i.e. continuous slider callback from within a GUIDE-created GUI)

 
function untitled_OpeningFcn(hObject, eventdata, handles, varargin)
 
% Choose default command line output for untitled
handles.output = hObject;
 
% Update handles structure
guidata(hObject, handles);
 
set(handles.text1,'String',get(handles.slider1,'Value'))
 
handle.listener(handles.slider1,'ActionEvent',@updatetextbox);
%addlistener(handles.slider1,'ActionEvent',@updatetextbox); %using this variation does not work, either

And updatetextbox looks like this in a separate file (i.e. once it registers a slide movement, execution should jump inside updatetextbox and give me keyboard access, so I can at least see what inputs it got – but it does not happen (probably because I defined the listener inside, at the OpeningFcn level?).

function updatetextbox(varargin)
keyboard
slidval=get(handles.slider1,'Value');
set(handles.text1,'String',num2str(slidval));

If I define the listener in the main function, then there is a problem – it runs through a lot of times. I can catch one where the figure is plotted already (where varargout already exists), grab the handle, add the listener… and nothing happens (sigh).:

 
function varargout = untitled(varargin)
% UNTITLED M-file for untitled.fig
%  *** standard comment section ***
% See also: GUIDE, GUIDATA, GUIHANDLES
 
% Edit the above text to modify the response to help untitled
% Last Modified by GUIDE v2.5 11-Apr-2010 01:31:27
 
% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name',       mfilename, ...
                   'gui_Singleton',  gui_Singleton, ...
                   'gui_OpeningFcn', @untitled_OpeningFcn, ...
                   'gui_OutputFcn',  @untitled_OutputFcn, ...
                   'gui_LayoutFcn',  [] , ...
                   'gui_Callback',   []);
if nargin && ischar(varargin{1})
    gui_State.gui_Callback = str2func(varargin{1});
end
 
if nargout
    [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});
else
    gui_mainfcn(gui_State, varargin{:});
end
% End initialization code - DO NOT EDIT
 
% *** ADDED MY BIT HERE!!! ***
if exist('varargout')==1       %stopping main function once figure is up
   handles=guidata(varargout{1});      %grabbing the handles structure
   handle.listener(handles.slider1,'ActionEvent',@updatetextbox);  %adding listener
end

In this case, I think as the whole namespace disappears once this instance of the function runs through, the listener disappears with it, too.
(I’ll post this now, and continue in the next)