How I can call setState() of class A from Class B - flutter

Question

when I click on IconButton() to delete All items from the list movies I can't see that change until I reopen the page again...
anyone know how I could fix
this my infoPage(("class B")):
class InfoPage extends StatefulWidget {
int id;
int pageId;
InfoPage(this.id,this.pageId);
#override
_InfoPageState createState() => _InfoPageState(id,pageId);
}
class _InfoPageState extends State<InfoPage> {
var db = DatabaseHelper();
String title = "";
String about = "";
String rate = "";
String date = "";
int id;
int pageId;
_InfoPageState(this.id,this.pageId);
#override
void initState() {
super.initState();
if(pageId == 1){
_getMovie();
}
}
void _getMovie() async {
Movie thisMovie = await db.getMovie(id);
setState(() {
title = thisMovie.name;
about = thisMovie.description;
rate = thisMovie.rate;
date = thisMovie.date;
});
}
_deleteMovie() async{
await db.deleteMovie(id);
Navigator.pop(context);
setState(() {
CardsListViewState(pageId).deleteAllList();
});
}
#override
Widget build(BuildContext context) {
Navigator.canPop(context);
return Scaffold(
body: Container(
child: Column(
children: <Widget>[
Container(
margin: EdgeInsets.only(bottom: 10),
child:Row(
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Expanded(
child: Container(),
),
Container(
margin: EdgeInsets.only(right: 10),
child: IconButton(
icon: Icon(Icons.delete,color: Color(0xffFC4D4D),),
onPressed: (){
_deleteMovie();
}
)
)
],
),
)
],
),
),
);
}
}
and this my CardsListView(("class A"))
class CardsListView extends StatefulWidget {
int whereComeFrom;
CardsListView(this.whereComeFrom);
#override
CardsListViewState createState() => CardsListViewState(whereComeFrom);
}
class CardsListViewState extends State<CardsListView> {
int whereComeFrom;
CardsListViewState(this.whereComeFrom);
var db = DatabaseHelper();
List mainList = [];
final List<Movie> movies = <Movie>[];
deleteAllList() async{
await db.deleteMovies();
setState(() {
movies.clear();
});
}
#override
void initState() {
super.initState();
_readUnites();
if(whereComeFrom == 1){
mainList = movies;
}
}
#override
Widget build(BuildContext context) {
return Scaffold(
body:
GridView.count(
crossAxisCount: 3,
addAutomaticKeepAlives: true,
childAspectRatio: (1/1.5),
children: List.generate(mainList.length, (index){
return CardUnite(mainList[index].name,mainList[index].id,whereComeFrom);
})
),
);
}

Answer 1

You can use a callback function from the parent class supplied to the child class.
Remember that functions are first class objects in Dart.
Just pass in a function that calls setState to the child and have the child call that function.