Saving the data to a dynamic list on another screen based on previous selection in flutter

Question

Am a completely new flutter dev. I am trying to save a document from a queried firestore list on another saved documents page like an add to cart functionality. Am passing doc id as arguments to another page from firestore so that I get data based on the previous selection. Now how can I send the firestore reference and save it to the other screen without navigating to it so that users are able to save their favorite docs on another page and access them? Here is my Assignment page that lists the docs based on the previous selection.

         class Assignments extends StatelessWidget {
                       final String programId;
                       final String yearId;
                       final String semesterId;
                       final String courseId;
                      const Assignments(
                   {Key key, this.programId, this.yearId, this.semesterId, 
                 this.courseId})
                       : super(key: key);

                          @override
                    Widget build(BuildContext context) {
                    return Scaffold(
                        appBar: CustomAppBar2(title: 'Assigment'.toUpperCase(),  ),
  body: Column(
    children: [
      Expanded(
        child: ContentArea(
            addPadding: false,
            child: StreamBuilder(
                stream:
                    getAssignment(programId, yearId, semesterId, courseId),
                builder: (context, snapshot) {
                  if (!snapshot.hasData) {
                    return const Center(
                      child: CircularProgressIndicator(
                          color: kOnSurfaceTextColorYellow),
                    );
                  }

                  return ListView.separated(
                    padding: UIParameters.screenPadding,
                    shrinkWrap: true,
                    itemCount: snapshot.data.docs.length,
                    itemBuilder: (BuildContext context, int index) {
                      final data = snapshot.data.docs[index];
                      return DisplayCard(
                        title: data['nameOfAssignment'],
                        icon: Icons.add, 
                     // Here is the action i want that should save the documment to 
                     // the SavedPage empty list without navigating to it
                         onTapIconSave: (){}
                        onTap: () => Get.to(Pdf(
                          nameOfAssignment: data['nameOfAssignment'],
                          pdfUrl: data['pdfUrl'],
                        )),
                      );
                    },
                    separatorBuilder: (BuildContext context, int index) {
                      return const SizedBox(
                        height: 10,
                      );
                    },
                  );
                })),
      ),
    ],
  ),
);

} }

Here is the SavedPage which may be similar to the cart page. Am not sure what to do in order to save the Document from the Assignment Page in a Dynamic growable list

                     class Saved extends StatefulWidget {
                       const Saved({ Key key }) : super(key: key);

                           @override
                           State<Saved> createState() => _SavedState();
                              }

                               class _SavedState extends State<Saved> {

                           @override
                             Widget build(BuildContext context) {
                return Scaffold(
                appBar: const CustomAppBar2(title: 'Saved'),
                body: Column(
                  children:  [],
  ),
);

} }

Answer 1

You can add a state management package like Provider or Bloc, also you could save your data in your local database and access them from there. I recommend Provider, easy to use, and its what you need.