参数类型 'ModalRoute<Object?>?' 无法分配给参数类型 'PageRoute<dynamic>'

The argument type 'ModalRoute<Object?>?' can't be assigned to the parameter type 'PageRoute<dynamic>'

最近我正在迁移到空安全。更新了 firebase_analytics:^8.0.2.

this.observer.subscribe(this, ModalRoute.of(context)) 现在面临问题;有人可以帮助传递第二个参数吗?

class _BookedClassDetailsPageState extends 
State<BookedClassDetailsPage> with SingleTickerProviderStateMixin, RouteAware{

late FirebaseAnalyticsObserver observer;

@override
void initState() {
 super.initState();
 observer=widget.repository.analyticsService.getAnalyticsObserver();
 observer.analytics.setCurrentScreen(
     screenName: 'Booked Class Page',
     screenClassOverride: 'BookedClassPage'
 );

}

@override
void didChangeDependencies() {
  super.didChangeDependencies();
  observer.subscribe(this, ModalRoute.of(context));
}
 @override
 void dispose() {
    observer.unsubscribe(this);
    super.dispose();
 }
}

你可以通过关键词“as”将类型ModalRoute改为PageRoute,像这样:

observer.subscribe(this, ModalRoute.of(context) as PageRoute);