Configure for app fails with "Too many input arguments" when component has an empty constructor

I created the default custome component in the appdesigner. Added an empty constructor and tried to "configure for apps". If fails with "Too many input arguments". I tried adding if nargin > 0, end; Still get the error.

classdef comp1 < matlab.ui.componentcontainer.ComponentContainer

    % Properties that correspond to underlying components
    properties (Access = private, Transient, NonCopyable)
    end

    
    methods 
        %ctor - if I remove this, I can register without errors
        function comp = comp1
            
        end
    end
    

    methods (Access = protected)
        
        % Code that executes when the value of a public property is changed
        function update(comp)
            % Use this function to update the underlying components
            
        end

        % Create the underlying components
        function setup(comp)

            comp.Position = [1 1 320 240];
            comp.BackgroundColor = [0.94 0.94 0.94];
        end
    end
end

Answer 1

[Lokesh]

Hello Mark,

I understand that you are experiencing "Too many input arguments" error when trying to configure your custom component in App Designer.

This issue arises because the constructor in the custom component class is not handling input arguments properly.

The constructor should be designed to accept a variable number of input arguments using 'varargin'. This ensures that it can handle any arguments MATLAB might pass during the configuration process. Here's a modified version of the class:

classdef comp1 < matlab.ui.componentcontainer.ComponentContainer
    % Properties that correspond to underlying components
    properties (Access = private, Transient, NonCopyable)        
    end   
    
    methods 
        % Constructor - handle variable input arguments
        function comp = comp1(varargin)         
            if nargin > 0            
                % Handle constructor input arguments if necessary           
                % Example: Set properties based on input arguments             
            end            
        end        
    end    
    
    methods (Access = protected)              
        % Code that executes when the value of a public property is changed       
        function update(comp)           
            % Use this function to update the underlying components           
        end
              
        % Create the underlying components       
        function setup(comp)          
            comp.Position = [1 1 320 240];        
            comp.BackgroundColor = [0.94 0.94 0.94];            
        end        
    end    
end

By using 'varargin', the constructor can now accept any number of arguments, preventing the "Too many input arguments" error during registration. This approach maintains flexibility in handling inputs as needed.

Hope this helps!