Matlab slider pass value to event handler

I am new of Matlab GUI and i have the following problem. I have declared a slider control and his properties, and i have added a listerner to the callback and to the PostSet event handler (i think that it is tecnically called event handler) as you can see below:

function [] = HandlerSlide()
%HANDLERSLIDE Summary of this function goes here
%   Detailed explanation goes here
clf;
due = '2';
hSlider = uicontrol(                ...
    'Style','slider',               ...
    'Callback',@(s,e) disp(['hello ',num2str(due),' asdad']),...
    'Position', [400 30 200 20]     ... %[x,y, widht, height]
);
hListener = addlistener(hSlider,'Value','PostSet',@pippo);

end

function [] = pippo(s,e)

disp('ciao');

end

As you can see i have used parameter "due" in the Callback handler (the anonymous function). Now i would like to pass parameter to use in the "pippo" function without declare it as anonymous function. Is it possible? In other words i would like to declare "hListerner" like this:

hListener = addlistener(hSlider,'Value','PostSet',@pippo{parameter1,parameter2, etc ...});

function[] = pippo(s,e, parameter1, parameter2, etc ...)

Beside how can i use in the main the value returned by "pippo"?

thank you in advance :D

Answer 1

[Anthony Poulin]

Hi,

If you want to pass parameter with your callback you can do like this:

 hListener = addlistener(hSlider,'Value','PostSet',@{pippo,parameter1,parameter2, etc ...});

Then the declaration of your function is like you said:

function pippo(src,event,parameter1, parameter2, etc...)

For the second question, I'm not sure to ask correctly. Because it is a function the variable you create executing your callback are in your function workspace and be destroyed at the end of the callback execution.

But if you want to pass a value (or many) to your main workspase (the 'base' workspace), you can use the matlab function "assignin", (look also to evalin which is helpful to catch a value from a worskpace to your function worksspace)

Answer 2

[Duccio Mugnaini]

Thank you for answer, but if i write:

hListener = addlistener(hSlider,'Value','PostSet',@{pippo,var1,var2});

Matlab underline '{' '}' and give the following parse error: usage might be invalid MATLAB syntax.

Answer 3

[Anthony Poulin]

OK, you're right is see my mistake: I worte "@{pippo...", but it's "{@pippo..." the correct syntax.

I never used the addlistener fonction, so I don't know if it's work well with this function but I have allready do thing like this:

hSlider = uicontrol(                ...
  'Style','slider',               ...
  'Callback',{@pippo,parameter1,parameter2, etc ...},...
  'Position', [400 30 200 20]     ... %[x,y, widht, height]);

Is it helpfull?

Answer 4

[Duccio Mugnaini]

Yes that is helpfull to pass parameter to Callback method :D But if i use the same style to set the listener as you suggest

hListener = addlistener(hSlider,'Value','PostSet',{@pippo,var1,var2});

then the error is disappeared but when i run the function there is the following error:

Error using HandlerSlide (line 56)
No method 'addlistener' with matching signature found. Callback must be a function handle.

:(