Cacher is the code snippet organizer for pro developers

rb=rg.getCheckedRadioButtonId(); //get checked radiobutton id in a radiogroup
selectedradioButton=findViewById(rb);        
String s=selectedradioButton.getText().toString();

//check if anything is selected in a radiogroup or not

if (rg.getCheckedRadioButtonId() == -1){
    //Nothing is selected
}

//to select a radioButton programmatically
radioButton.setChecked(true);