How to change an uitable from a listbox? (GUIDE)

Hello,

I'm doing a project with GUIDE and I have a problem. The programa have two EditText with one PushButton, one Listbox and one uitable. The user through the first EditText insert one variable to the listbox and with the second EditText the number of rows of the uitable (the columns are fixed) with the following code in the PushButton Callback:

variables = str2double(get(handles.Number,'String'));
columns = 4;
num_elem = cell(variables,columns);
num_elem(:,:)={''};
set(handles.uitable1,'Data',num_elem)
set(handles.uitable1,'ColumnEditable',true(1,columns))

a = get(handles.Name,'String');
str_part = a;
old_str = get(handles.listbox1,'String');
new_str = strvcat(old_str, str_part);
set(handles.listbox1,'String',new_str)

Till now all is correct, the problem commes when there are for instance 3 variables, with 4, 6 and 8 rows and I want to click in the first one and the rows must change to 4, and if a click in the third must change to 8. But I don't know how to do it, the rows keep without change. My code is the following in the Listbox Callback:

num = get(handles.listbox1,'Value');
variables = str2double(get(handles.Numero,'String'));

switch num
  case 1
      a = zeros(variables,4);
      a(:,2)=1;
      a(:,4)=1;
      set(handles.uitable1, 'Data', a);
  case 2
      a = zeros(variables,4);
      a(:,2)=1;
      a(:,4)=1;
      set(handles.uitable1, 'Data', a);
end

• The variable a is do to the uitable must be refill with 1 and 0.Other problem is that there will be as much variables as we want.

Thank you very much