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());