Why buttondownfcn of pushbutton not work in a classdef file ??!!!

I just want to build a pushbutton in a class defintion with a buttondown callback. But there is no reaction if I click the button.

If I change the 'buttondownfcn' to 'callback'. Then it will work. But I indeed need 'buttondownfcn' for my function.

Is this a Matlab bug or I missed something? I am using matlab 2011b.

Thanks guys.

classdef testBtnCbk
    %TESTBTNCBK Summary of this class goes here
    %   Detailed explanation goes here

      properties
      end

      methods
          function obj = testBtnCbk()
              hfig = figure;
              oTab.hBtn = uicontrol('style', 'pushbutton',...
                                   'parent', hfig, ... 
                                   'backgroundcolor', [0 0 0], ...
                                   'foregroundcolor', [1 1 1], ...
                                   'string', 'hello', ...
                                   'Units', 'pixel', ...
                                   'buttondownfcn', @obj.pshbtnDwnCbk, ...
                                   'Position', [100 100 100 100]);        
          end

          function pshbtnDwnCbk(obj, ~, ~)
              msgbox('hello')
          end        
      end

end

Answer 1

[Song]

Ok, I find out why ... I have to set the property

'enable' -> 'inactive'

to invoke the callback.

[Adam]

Ah, I'd never really noticed that aspect of functionality. That will effectively disable its use as a pushbutton though so you would have to change enable back to 'on' at times you want it to actually behave as a pushbutton rather than having its buttondownfcn active.

Answer 2

[Adam]

Yes, I just did a test and ButtonDownFcn does appear not to work. This is independent of being in a class. It is the same on command line.

However, I can think of no possible reason why you would need to use ButtonDownFcn on a pushbutton given that 'Callback' does exactly that.

[Song]

I want to realize a function in GUI after pushing pushbutton then move the button if i hold the mouse left button and move. In this case, I need to address buttondown / buttonup function instead of click callback.