Using functions on callbacks of a GUI - function

Question

I'm using GUIDE to create an interface where a function [x,y]=function(a,b,c,d) will be executed when the button is clicked. Im having problems to get this to work. GUIDE creates an autogenerated function with the syntax varargout = LineasA(varargin).
I'm calling the GUI using this syntax [x,y]=LineasA(a,b,c,d).
Errors I get are:
Error in ==> LineasA>LineasA_OutputFcn at 73
varargout{1} = handles.output;
??? Error using ==> feval
Output argument "varargout{2}" (and maybe others) not assigned during call to
"C:\Users\ZeTa\Documents\MATLAB\ImagenB\LineasA.m>LineasA_OutputFcn".
Error in ==> gui_mainfcn at 263
[varargout{1:nargout}] = feval(gui_State.gui_OutputFcn, gui_hFigure, [],
gui_Handles);
Error in ==> LineasA at 40
[varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});
Error in ==> ImagenB at 17
[MatrizB,Cuenta]=LineasA(Cuenta,waveformObj,channelObj,MatrizB);

Answer 1

You have to be clear where you are getting the inputs to this function, and where you want the outputs to go. It is proper coding to store the inputs and outputs in the handles struct that is passed into the callback. Also, the proper callback structure is:
LineasA(hObject, eventdata, handles)
However, if you insist on calling and storing from the base workspace, you can do as follows:
LineasA(hObject, eventdata, handles)
% grab values from base workspace
Cuenta = evalin('base', 'Cuenta');
waveformObj = evalin('base', 'waveformObj');
channelObj = evalin('base', 'channelObj');
MatrizB = evalin('base', 'MatrizB');
% the rest of your code
% assign outputs
assignin('base', 'MatrizB', matrizB);
assignin('base', 'Cuenta', Cuenta);
end
However I recommend getting those values in the handles structure and not to use evalin and assignin, they are usually bad coding techniques.