Matlab - Funcion line visible

function ejemploweb_OpeningFcn(hObject, eventdata, handles, varargin)

% This function has no output args, see OutputFcn.

% hObject    handle to figure

% eventdata  reserved - to be defined in a future version of MATLAB

% handles    structure with handles and user data (see GUIDATA)

% varargin   command line arguments to ejemploweb (see VARARGIN)

% Choose default command line output for ejemploweb

handles.output = hObject;

handles.linea = [];

% Update handles structure

guidata(hObject, handles);

function checkbox1_Callback(hObject, eventdata, handles)

% hObject    handle to checkbox1 (see GCBO)

% eventdata  reserved - to be defined in a future version of MATLAB

% handles    structure with handles and user data (see GUIDATA)

grilla = get(hObject,'Value');

if isempty(handles.linea)

    handles.linea = line([1; 10],[2; 20],'LineStyle','-');

end

if grilla==1

    set(handles.linea,'Visible','on');

else

    set(handles.linea,'Visible','off');

end

guidata(hObject, handles);