MATLAB: How to assign a class method as a ClickedCallback

clickedcallbackfunction handleobject-orientedoop

The class may change, but the method names are the same.
classdef BaseClass < handle
    properties
        p = []
    end
    methods
        function h = get_save_handle( obj )
            h = @obj.save;
        end
    end
end
classdef Class1 < BaseClass
    properties
        p1 = []
    end
    
    methods
        function save( obj )
            % ...

        end
    end
end
classdef Class2 < BaseClass
    properties
        p2 = []
    end
    
    methods
        function save( obj )
            % ...
        end
    end
end
I need to change the callback of a save button in my UI depending on the user's data, which will determine which class is used. So if I'm using class1, the ClickedCallback of my save button needs to be class1.save(), etc. Here is how I assign the callback:
switch data_type
    case 'Class1'
        save_data = Class1();
    case 'Class2'
        save_data = Class2();
end
saveUIButton.set( 'ClickedCallback', { save_data.get_save_handle(), f }, 'UserData', save_data ) % 'f' is my figure.
But when I click the save button, the varargin{:} causes an error because the 'save' function arguments aren't compatible:
Error using Class1/save
Too many input arguments.
Error in BaseClass>@(varargin)obj.save(varargin{:}) (line 82)
            h = @obj.save;
 
Error while evaluating PushTool ClickedCallback.

Best Answer

    methods
        function h = get_save_handle( obj )
            h = @obj.save;
        end
    end
The name of the method is save.
    methods
        function h = get_save_handle( obj )
            h = @save;
        end
    end
When that function handle gets executed, MATLAB will use the input arguments with which it was called to determine which function or method named save will be called. If the input isa Class1 the Class1 save method will be called. If it isa Class2 then Class2's save method will be called. If it's neither, the built-in save function will be called.
For example:
h = @plot; % No class information required to create h
% Sample data
g = graph(bucky);
x = 1:10;
figure
h(g) % the plot method for graph objects gets called
figure
h(x) % the built-in plot function (for double data) gets called
HOWEVER, I would be wary about overloading save for your objects, as it has kind of an important meaning already in MATLAB. If you're looking to customize what happens when you save your objects, you probably want to overload the saveobj and loadobj functions instead as described in this topic in the documentation. If your save method is intended to do something like writing the data to some other type of file rather than a MAT-file, I'd suggest a slightly longer and more descriptive name, something like saveTo<fileType>File (saveToTextFile or saveToTXTFile as an example.)
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