Can I give input arguments while referencing a callback function?

I'm new to object oriented MATLAB so bear with me.

I am plotting some data from my class S, as

 Plot(s.X{i},s.Y{i},s.Data{i},...
    set(gcf,'Name','Data1');
    filepath = s.DirPath{1,i}); 
    set(gca,'ButtonDownFcn',@mycallback);

Now I want to give this 'filepath' as one of the input argument for my callback function. But when I try to use filepath, it doesn't recognize it.

I also tried

 set(gcf,'Tag',s.DirPath{1,i}); 
 set(gca,'ButtonDownFcn',@mycallback);

and

 get('Tag');

within my callback function.

Any help?

Answer 1

[Geoff Hayes]

Soumyatha - I don't think that it is a good idea to overwrite the Tag property of your figure with

 set(gcf,'Tag',s.DirPath{1,i});

This would (to my understanding) change the name of the figure and would make it difficult to reference if you needed to elsewhere in the app.

So to pass in this file path parameter, you would do something like

 set(gca,'ButtonDownFcn',{@mycallback, filepath});

and your callback signature would become

 function mycallback(source, eventdata, filepath)

This should work, but you have to remember that the filepath will always have the value that was set to this variable when the callback was assigned. So if this variable ever gets modified, the callback will not see the change.

An alternative, is to nest your callback within the parent function which allows the nested function to access the variables defined within its parent. For example,

 function myMainFunc

     % some code here

     Plot(s.X{i},s.Y{i},s.Data{i},...
     set(gcf,'Name','Data1');
     filepath = s.DirPath{1,i}); 
     set(gca,'ButtonDownFcn',@mycallback);

     function mycallback(source, eventdata)

         % some code here

         % use filepath
         save(filepath,....);
     end
 end

Try nesting your callback. That way, if filepath is changed by some other callback, then mycallback will be able to access the changed variable.

[Soumyatha Gavvala]

I have a fixed filepath that only changes on different runs. This worked for me, thanks a lot!