import 'package:flutter/material.dart'; import 'navigation_observer.dart'; mixin RouteAwareState on State implements RouteAware { @override void didPopNext() { // When returning to this route, subclasses can override to refresh state. } void subscribeRouteAware() { WidgetsBinding.instance.addPostFrameCallback((_) { final route = ModalRoute.of(context); if (route != null) { routeObserver.subscribe(this, route); } }); } void unsubscribeRouteAware() { routeObserver.unsubscribe(this); } }