callback function handle syntax inside objects?

I have an object that generates a gui and controls some external equipment. I am trying to set things up so that a particular button press on the gui sends a particular command to the external equipment (without success). The command is sent using one of the object methods.

Example:
cg=CCUCGUI('10.0.1.1');
cg.navi('up');

The above code works, but my numerous attempts to create a callback inside the object contructor have failed miserably.

I have tried the following and more, but my understanding of callback function handle syntax is clearly insufficient to the task.

set(obj.guiobj.buttonup,'Callback','obj.navi(''up'');');
%Note the above executes, but 'obj' does not exist in main MATLAB workspace
set(obj.guiobj.buttonup,'Callback',@() obj.navi('up'));
set(obj.guiobj.buttonup,'Callback',{@() obj.navi('up')});
set(obj.guiobj.buttonup,'Callback',{@('up') obj.navi});
set(obj.guiobj.buttonup,'Callback'{@obj.navi,'up'});
tmp='up';set(obj.guiobj.buttonup,'Callback',@(tmp) obj.navi);
tmp='up';set(obj.guiobj.buttonup,'Callback',{@(tmp), obj.navi});

Any help would be appreciated, Thanks, Sean

[Jan]

A very nice collection!

Answer 1

[Sean]

I have found a way to accomplish what I was trying to accomplish, although it isn't by using function handles. In case anyone else is trying to do something similar, here is the method I used:

1) Get the output object instance name as soon as the constructor starts running by:

cvh=cellstr(char(com.mathworks.mlservices.MLCommandHistoryServices.getSessionHistory));
objname=strtok(char(cvh(end)),'=');         
clear cvh

2) Use the output object instance name in setting the callback:

set(obj.guiobj.buttonup,'Callback',strcat(objname,'.navi(''up'');'));

Since string based callback assignment executes in the base workspace, this directly simulates the equivalent command line action (and thus works).

Credit for the solution idea to Brad Stiritz: http://www.mathworks.com/matlabcentral/answers/16693-within-a-function-get-complete-command-line-calling-text-a-la-dbstack

If anyone can answer the question as asked (i.e. about function handles), I am still interested for future reference though. :)