addListener method

RemoveListener addListener(
  1. ListenerCallback<State> listener
)

Subscribes to this object.

The listener callback will be called whenever state changes.

To remove this listener, call the function returned by addListener

final removeListener = example.addListener((value) => ...);
removeListener();

Implementation

RemoveListener addListener(ListenerCallback<State> listener) {
  final listenerEntry = _ListenerEntry(listener);
  _listeners.add(listenerEntry);
  return () {
    if (listenerEntry.list != null) {
      listenerEntry.unlink();
    }
  };
}