RadioButtonGroup - Managing group value
When you click on one of the group's option, the onChange({checkedItemValue, checkedItemIndex}) callback will be called, having the selected item's value and index as arguments.
By default, the <RadioRadioButtonGroup /> is uncontrolled, changing the checked value when the user clicks on the radio buttons. If you don't specify a defaultRadioValue, no value will be initially selected.
You can also use the defaultRadioValue prop for uncontrolled behaviour, which will select the given value in the <RadioRadioButtonGroup />.
To have a controlled <RadioRadioButtonGroup />, use the radioValue prop in combination with onChange to react to changes.