MATLAB Answers


How to pass a superclass method as a calback?

Asked by Mario Koddenbrock on 7 Dec 2017
Latest activity Commented on by Guillaume
on 7 Dec 2017
Does anybody know how to pass a superclass function as a calback?
For example a button callback:
btn = uicontrol('Style', 'pushbutton', 'String', 'Example',...
'Position', [20 20 50 20],...
'Callback', @(~, ~)methodFromSuperclass@superclass(obj));
But this one gives an error:
"@" Within a method, a superclass method of the same name is called by saying method@superclass. The left operand of "@" must be the method name.
Thanks, Mario


Sign in to comment.

1 Answer

Answer by Mario Koddenbrock on 7 Dec 2017
 Accepted Answer

Okay I found the solution:
btn = uicontrol('Style', 'pushbutton', 'String', 'Example',...
'Position', [20 20 50 20],...
'Callback', @(~, ~)obj.methodFromSuperclass());
if the methodFromSuperclass is not used in the subclass.

  1 Comment

Yes, the @ syntax is only used
  • in the constructor when you want to call the superclass constructor
  • in a class method when you want to invoke a superclass method that has been overriden in the class.
It is never used by a user of the class. The whole point of inheritance is that all methods from all superclasses appear as normal methods of the derived class, so from a user point of view, either
obj.inheritedmethod() %dot notation
inheritedmethod(obj) %functional notation

Sign in to comment.