Problem accessing member in OOP

I am trying to write a custom login dialog UI as a class.

I have done all logins callbacks so far (or I think so) but if I press the login button the loginCallback gets executed.

My Problem is that I can not access any member inside of loginCallback ? Everything seems to be empty and I do not understand why.

Also tried it here with a test variable which is of an easy double type m_test is also empty but gets initialised correct by the constructor.

classdef LoginDialog
    %LOGINDIALOG Summary of this class goes here
    %   This class provides the login UI and backend for the 
    %   loginDialog 
    
    properties
        main_fig;%mainfigure
        m_login_btn;%login btn;
        m_login_dropDown;%displays previous logins
        m_login_chk;%gives ability to choose from previous logins
        m_serverIp_txt;%enter login ip
        m_serverUsr_txt;
        m_serverpw_txt;
        m_serverIp_lbl;%enter login ip
        m_serverUsr_lbl;
        m_serverpw_lbl;
        m_logins; % keeps all the past login fields
        m_test;
    end
    
    methods
        %default constructor
        function obj = LoginDialog()
            %% definde UI
            obj.main_fig = uifigure;
            obj.main_fig.Resize = 0; 
            %% define button
            obj.m_login_btn = uibutton(obj.main_fig);
            obj.m_login_btn.Text = "Login";
            obj.m_login_btn.Position = [obj.main_fig.Position(3)/2 - obj.m_login_btn.Position(3) / 2,...
                20,100,20];
            obj.m_login_btn.ButtonPushedFcn = @obj.loginCallback;
            %% define dropDown
            obj.m_login_dropDown = uidropdown(obj.main_fig);
            obj.m_login_dropDown.Position = [obj.main_fig.Position(3)-obj.m_login_dropDown.Position(3),...
                obj.main_fig.Position(4)-obj.m_login_dropDown.Position(4),100,20];
            obj.m_login_dropDown.Items = cell(1,0);
            obj.m_login_dropDown.Visible = 0; 
            %% define server ip
            obj.m_serverIp_lbl = uilabel(obj.main_fig);
            obj.m_serverIp_lbl.Text = "Server Ip:";
            obj.m_serverIp_lbl.Position = [obj.main_fig.Position(3)/2 - obj.m_login_btn.Position(3) / 2 - 60,...
                150,100,20];
            %edit field
            obj.m_serverIp_txt = uieditfield(obj.main_fig);
            obj.m_serverIp_txt.Position = [obj.main_fig.Position(3)/2 - obj.m_login_btn.Position(3) / 2,...
                150,100,20];
            %%define server username
            obj.m_serverUsr_lbl = uilabel(obj.main_fig);
            obj.m_serverUsr_lbl.Text = "Username:";
            obj.m_serverUsr_lbl.Position = [obj.main_fig.Position(3)/2 - obj.m_login_btn.Position(3) / 2 - 60,...
                125,100,20];
            % edit field
            obj.m_serverUsr_txt = uieditfield(obj.main_fig);
            obj.m_serverUsr_txt.Position = [obj.main_fig.Position(3)/2 - obj.m_login_btn.Position(3) / 2,...
                125,100,20];
            %% define server pw
            obj.m_serverpw_lbl = uilabel(obj.main_fig);
            obj.m_serverpw_lbl.Text = "Password:";
            obj.m_serverpw_lbl.Position = [obj.main_fig.Position(3)/2 - obj.m_login_btn.Position(3) / 2 - 60,...
                100,100,20];
            % edit field
            obj.m_serverpw_txt = uieditfield(obj.main_fig);
            obj.m_serverpw_txt.Position = [obj.main_fig.Position(3)/2 - obj.m_login_btn.Position(3) / 2,...
                100,100,20];
            %% define chk box 
            obj.m_login_chk = uicheckbox(obj.main_fig);
            obj.m_login_chk.Text = "Use existing login";
            obj.m_login_chk.Position = [obj.m_login_dropDown.Position(1) - obj.m_login_chk.Position(3)*1.5,obj.m_login_dropDown.Position(2)-5,120,30];
            obj.m_login_chk.ValueChangedFcn = @(cbx,event) cBoxChanged(obj,obj.m_login_chk);
            % chk box value    

            %% load logins
            if(exist('savedLogins.mat','file') ~= 0)
               obj.m_logins = load('savedLogins'); 
               if(~isempty(obj.m_logins.m_savedLogins))
                   identifiers = obj.m_logins.m_savedLogins{:,1};
                   obj.m_login_dropDown.Items = identifiers;
               end
            end
            obj.m_test = 33;
        end
        %% method which gets executed on checkbox changed
        function obj = cBoxChanged(obj,cbx)
            val = cbx.Value;
            if (val == 1)
                obj.m_login_dropDown.Visible = 'on';
                obj.m_serverIp_txt.Enable = 0;
                obj.m_serverUsr_txt.Enable = 0;
                obj.m_serverpw_txt.Enable = 0;
            else
                obj.m_login_dropDown.Visible = 'off';
                obj.m_serverIp_txt.Enable = 1;
                obj.m_serverUsr_txt.Enable = 1;
                obj.m_serverpw_txt.Enable = 1;
            end
        end
        function lastLogins = getLastLogin(obj)
            if(exist('savedLogins.mat','file') ~= 0)
               obj.m_logins = load('savedLogins'); 
               lastLogins = obj.m_logins;
            end
        end
        %% method which gets executed if login button gets pressed

         function [ip,usr,pw] = loginCallback(obj,src,~)
            
% % % %             can not access any members here??
% % % %     
         end
    
        
    end
end

Answer 1

[Mohammad Sami]

You need to change this to a handle class instead of a value class.

classdef LoginDialog < handle