how to update data in flutter using provider?

Question

I'm using Provider to receive data to a screen and i have a function with not required parameters in my provider class and the data came normally. I have an icon in the appbar to open a bottomsheet, which i gave a parameter to the function so i press a button in the bottomsheet to update the existing data with the new data. I tried many times but it did not work with me because i still learning state management using provider. Can any one tell me how to it programmaticallye?

Here's the code..

     import 'package:conditional_builder_null_safety/conditional_builder_null_safety.dart';
      import 'package:flutter/cupertino.dart';
     import 'package:flutter/material.dart';
     import 'package:provider/provider.dart';
     import 'package:rick_and_morty/pages/character_details.dart';
       import 'package:rick_and_morty/pages/widgets/character_item.dart';
      import 'package:rick_and_morty/pages/widgets/chip_choice.dart';
      import 'package:rick_and_morty/providers/my_provides.dart';

       import '../models/users.dart';

         class HomeLayout extends StatefulWidget {
         const HomeLayout({Key? key}) : super(key: key);
  
        @override
         State<HomeLayout> createState() => _HomeLayoutState();
       }

        class _HomeLayoutState extends State<HomeLayout> {


       @override
       Widget build(BuildContext context) {
       return Scaffold(
          appBar: AppBar(
            title: const Center(child: Text('Users')),
            actions: [
              IconButton(
                  padding: const EdgeInsets.only(right: 25),
                  onPressed: (){
                    showModalBottomSheet(
                        context: context,
                        builder: (context) =>
                            Column(
                              children:  [
                                Container(
                                  alignment: Alignment.center,
                                  color: Colors.black,
                                  width: double.infinity,
                                  height: 50,
                                  child: const Text('Filter  Characters',
          style:TextStyle(
          color:Colors.white
           ,fontSize: 22),),
                                ),
                                const ChoiceChipWidget(),
                              ],
                            )
                    );

                  },
                  icon: const Icon(Icons.filter_list_sharp,size: 40,)),

            ],
          ),

          body: FutureBuilder(
                future: Provider.of<MyProvider>(context).getAllCharacters(),
                  builder: (context, snapshot){
                    if(snapshot.hasData){
                      List<RickModel> users = snapshot.data!;
                      return GridView.builder(
                          gridDelegate:  const SliverGridDelegateWithFixedCrossAxisCount(
                            crossAxisCount: 2,
                            childAspectRatio: 2 / 3,
                            crossAxisSpacing: 1,
                            mainAxisSpacing: 1,
                          ),
                          itemCount: users.length,
                          itemBuilder: (context,index) =>
                              CharacterItem(
                                rickModel: users[index],
                                widget:CharacterDetails(rickModel: users[index]),
                              )
                      );
                    } else{
                      return Center(child: CircularProgressIndicator());
                    }
                  }
              )

      );


        }
        }

      import 'package:flutter/material.dart';

      import '../models/users.dart';
        import '../repository/my_repository.dart';

      class MyProvider extends ChangeNotifier{
       MyProvider(this._myRepository);

        final MyRepository _myRepository;


        List<RickModel> _allRickCharacters =[];

        List<RickModel> get allRickCharacters => _allRickCharacters;

        Future<List<RickModel>> getAllCharacters({String? species, String? gender, String? status }) async{
        await _myRepository.getAllCharacters(species: species, gender: gender, status: status)
        .then((allRickCharacters){
       _allRickCharacters = allRickCharacters;
       });
        return _allRickCharacters;

      }


       }

any one can help me in this issue?

Answer 1

I think it just missing notifyListeners . Also you dont need to use await and .then at the same time. I will prefer await

  Future<List<RickModel>> getAllCharacters({
    String? species,
    String? gender,
    String? status,
  }) async {
    final allRickCharacters = await _myRepository.getAllCharacters(
        species: species, gender: gender, status: status);
    _allRickCharacters = allRickCharacters;
    notifyListeners(); //this
    return _allRickCharacters; // we may can skip return
  }