initState method

@override void initState()

Called when the app creates a radio group. This needs to be called specifically to set default values in the RadioGroupController for this radio group.

Implementation

@override
void initState() {
  super.initState();

  if (widget.key != null) {
    if (widget.key is! GlobalKey<RadioGroupState>) {
      throw InvalidKeyTypeException();
    }

    // Let the controller know who its radio group is.
    widget._controller.myRadioGroupKey =
        widget.key as GlobalKey<RadioGroupState<T>>;
  }

  // Set default starting value.
  if (widget.indexOfDefault < 0) {
    _value = null;
  } else {
    _value = widget.values[widget.indexOfDefault];
  }
}