GWT - GXT - How to get Radio Button Value ?

Create radio

Radio radio = new Radio();
radio.setBoxLabel("Si");
radio.setValue(true);
radio.setValueAttribute("true");

Radio radio2 = new Radio();
radio2.setBoxLabel("No");
radio2.setValueAttribute("false");

RadioGroup radioGroup = new RadioGroup();
radioGroup.setFieldLabel("Afecto");
radioGroup.add(radio);
radioGroup.add(radio2);

get selected value

Boolean b = Boolean.parseBoolean(radioGroup.getValue().getValueAttribute());