addObserver abstract method

NavigatorListenerRegistration addObserver({
  1. NavigatorObserverCallback? onPushed,
  2. NavigatorObserverCallback? onPopped,
  3. NavigatorObserverCallback? onRemoved,
  4. NavigatorObserverOnReplacedCallback? onReplaced,
  5. NavigatorObserverCallback? onStartUserGesture,
  6. VoidCallback? onStopUserGesture,
})

Adds a child observer to be notified of NavigatorObserver events.

Callers should only specify the callbacks that they're interested in.

The returned NavigatorListenerRegistration can be used to unregister the listener via NavigatorListenerRegistration.dispose.

Implementation

NavigatorListenerRegistration addObserver({
  NavigatorObserverCallback? onPushed,
  NavigatorObserverCallback? onPopped,
  NavigatorObserverCallback? onRemoved,
  NavigatorObserverOnReplacedCallback? onReplaced,
  NavigatorObserverCallback? onStartUserGesture,
  VoidCallback? onStopUserGesture,
});