onStateChange method

void Function() onStateChange(
  1. void listener(
    1. LifecycleState from,
    2. LifecycleState to
    )
)

Implementation

void Function() onStateChange(
    void Function(LifecycleState from, LifecycleState to) listener) {
  _stateListeners.add(listener);
  return () => _stateListeners.remove(listener);
}