type 'List<Animal?>' is not a subtype of type 'List<Animal>?' of 'value'

[ElixirMike]

I am trying to get your simple example code working. When i select an animal an click "ok",
it throws the error:

type 'List<Animal?>' is not a subtype of type 'List?' of 'value'

using this code

static List<Animal> _animals = [
    Animal(id: 1, name: "Lion"),
    Animal(id: 2, name: "Flamingo"),
    Animal(id: 3, name: "Hippo"),
    Animal(id: 4, name: "Horse"),
    Animal(id: 5, name: "Tiger"),
    Animal(id: 6, name: "Penguin"),
    Animal(id: 7, name: "Spider"),
    Animal(id: 8, name: "Snake"),
    Animal(id: 9, name: "Bear"),
    Animal(id: 10, name: "Beaver"),
    Animal(id: 11, name: "Cat"),
    Animal(id: 12, name: "Fish"),
    Animal(id: 13, name: "Rabbit"),
    Animal(id: 14, name: "Mouse"),
    Animal(id: 15, name: "Dog"),
    Animal(id: 16, name: "Zebra"),
    Animal(id: 17, name: "Cow"),
    Animal(id: 18, name: "Frog"),
    Animal(id: 19, name: "Blue Jay"),
    Animal(id: 20, name: "Moose"),
    Animal(id: 21, name: "Gecko"),
    Animal(id: 22, name: "Kangaroo"),
    Animal(id: 23, name: "Shark"),
    Animal(id: 24, name: "Crocodile"),
    Animal(id: 25, name: "Owl"),
    Animal(id: 26, name: "Dragonfly"),
    Animal(id: 27, name: "Dolphin"),
  ];

 final _items = _animals
      .map((animal) => MultiSelectItem<Animal>(animal, animal.name))
      .toList();

MultiSelectDialogField(
                items: _items,
                title: Text("Animals"),
                selectedColor: Colors.blue,
                decoration: BoxDecoration(
                  color: Colors.blue.withOpacity(0.1),
                  borderRadius: BorderRadius.all(Radius.circular(40)),
                  border: Border.all(
                    color: Colors.blue,
                    width: 2,
                  ),
                ),
                buttonIcon: Icon(
                  Icons.pets,
                  color: Colors.blue,
                ),
                buttonText: Text(
                  "Favorite Animals",
                  style: TextStyle(
                    color: Colors.blue[800],
                    fontSize: 16,
                  ),
                ),
                onConfirm: (results) {
                  //_selectedAnimals = results;
                },
              ),

[johandavidcm]

final _items = _animals
      .map((animal) => MultiSelectItem<Animal?>(animal, animal.name))
      .toList();

Try this

[ElixirMike]

I'm really struggling to get this to work where I have a component that loads the data via async through initState() . Probably the most common way people are getting data for a list.

Do you have a small sample of code that shows how to load data, as well as define initialValues through initState and get the list to work properly?

[ElixirMike]

As an example, here is code which successfully loads data and it properly generates the list. But I cannot get the iniitialValues to work at all. In this example , I explicitly set the _selectedOptions to the first one of the list in the setState which is what initialValues is set to, but it doesn't load the option.

What am I missing?

import 'package:flutter/material.dart';
import 'package:multiselect_formfield/multiselect_formfield.dart';
import 'package:multi_select_flutter/multi_select_flutter.dart';
import '../../api/api_manager.dart';
import '../../utils/getFilterMap.dart';


class GBSelectCustomFilter extends StatefulWidget {
  final Map filter;
  final Map column;
  final int tableId;
  final Function removeFilter;
  final Function updateFilter;

  const GBSelectCustomFilter(
      {Key? key,
      required this.filter,
      required this.removeFilter,
      required this.updateFilter,
      required this.column,
      required this.tableId})
      : super(key: key);

  @override
  _GBSelectCustomFilterState createState() => _GBSelectCustomFilterState();
}

class _GBSelectCustomFilterState extends State<GBSelectCustomFilter> {
  List<MultiSelectItem<dynamic>> _items =[];
  List<dynamic> _selectedOptions = [];
  final _multiSelectKey = GlobalKey<FormFieldState>();

  @override
  void initState() {
    getListData();
    super.initState();
  }

  Future<void> getListData() async {
    List<dynamic> data =
        await ApiManager.getListData(widget.tableId, widget.column);

    this.setState(() {
      _items =data
      .map((e) => MultiSelectItem<dynamic>(e, e['option']))
      .toList();
       _selectedOptions = [data[0]];
    });
  }

  @override
  Widget build(BuildContext context) {
    Map localFilter = widget.filter;
    return Container(
      margin: EdgeInsets.only(left: 20, right: 20, top: 10),
      child: Column(
        children: [
          MultiSelectDialogField(
              key: _multiSelectKey,
              items: _items,
              initialValue: _selectedOptions,
              title: Text("Colors"),
              selectedColor: Colors.blue,
              decoration: BoxDecoration(
                color: Colors.blue.withOpacity(0.1),
                borderRadius: BorderRadius.all(Radius.circular(40)),
                border: Border.all(
                  color: Colors.blue,
                  width: 2,
                ),
              ),
              buttonIcon: Icon(
                Icons.pets,
                color: Colors.blue,
              ),
              buttonText: Text(
                "Favorite Animals",
                style: TextStyle(
                  color: Colors.blue[800],
                  fontSize: 16,
                ),
              ),
              onConfirm: (results) {
                //_selectedAnimals = results;
              },
            ),
        ],
      ),
    );
  }
}

[UMUTARPT]

@johandavidcm can't assign list to items this way. It gives an error like this:
The argument type 'List<MultiSelectItem<CompanyIntegration?>>' can't be assigned to the parameter type 'List<MultiSelectItem<Object>>'.

[tmsbrndz]

So how do we set the value of initialValue? I tried it like @ElixirMike does.

[pankti16]

Same problem here.

[pankti16]

Trying @johandavidcm helped me

[adamsfru]

Try changing these lines in the example.

MultiSelectChipField<Animal?>(

List<Animal?> _selectedAnimals = [_animals[4], _animals[7], _animals[9]];

initialValue: _selectedAnimals,