Flutter list, chips and MultiSelect - flutter

Question

I am trying to transfer the result of a query to a list but it is not working properly.
Below you will find the source code, it will be more clear.
I'm getting this error "type 'List' is not a subtype of type 'List'"
if the error is clear, I do not understand how to fix that.
I would like to get _allResults (contextName) into the list _context.
Many thanks for your help.
import 'package:flutter/material.dart';
import 'package:flutter/cupertino.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:gtd_official_sharped_focused/models/context.dart';
import 'package:multi_select_flutter/multi_select_flutter.dart';
String taskImportant;
String taskUrgent;
class EngagePage_Sept_2021 extends StatefulWidget {
EngagePage_Sept_2021({Key key, }):super(key:key);//this.title}) : super(key: key);
// final String title;
#override
_EngagePage_Sept_2021State createState() => _EngagePage_Sept_2021State();
}
class _EngagePage_Sept_2021State extends State<EngagePage_Sept_2021> {
TextEditingController _searchController = TextEditingController();
Future resultsLoaded;
List _allResults = [];
List _resultsList = [];
#override
void initState() {
super.initState();
_selectedContext = _allResults;//_context;
_searchController.addListener(_onSearchChanged);
}
#override
void dispose(){
_searchController.removeListener(_onSearchChanged);
_searchController.dispose();
super.dispose();
}
#override
void didChangeDependencies() {
super.didChangeDependencies();
resultsLoaded = getUsersListOfTasksStreamSnapshots();
}
_onSearchChanged() {
searchResultsList();
}
/*static List<Contexts> _monTest = [
Contexts(contextName: ),
];
*/
static List<Contexts> _context = [. //Here, I would prefer to store the data.docs
Contexts(id: '1', contextName: "name 1"),
Contexts(id: '2', contextName: "name 2"),
Contexts(id: '3', contextName: "name 3"),
];
// static List<Contexts> _test = _allResults;
final _itemsContext = _context
.map((context) => MultiSelectItem<Contexts>(context, context.contextName))
.toList();
List<Contexts> _selectedContext = [];
final _multiSelectKeyContext = GlobalKey<FormFieldState>();
final _multiSelectKeyStatus = GlobalKey<FormFieldState>();
final _multiSelectKey4 = GlobalKey<FormFieldState>();
final _multiSelectKeyTime = GlobalKey<FormFieldState>();
searchResultsList() {
var showResults = [];
if(_searchController.text != "") {
for(var taskSnapshot in _allResults){
var title = Contexts.fromSnapshot(taskSnapshot).contextName.toLowerCase();
if(title.contains(_searchController.text.toLowerCase())) {
showResults.add(taskSnapshot);
}
}
} else {
showResults = List.from(_allResults);
}
setState(() {
_resultsList = showResults;
});
}
getUsersListOfTasksStreamSnapshots() async {
var data = await FirebaseFirestore.instance
.collection('Users')
.doc(FirebaseAuth.instance.currentUser.uid)
.collection('contexts')
.get();
setState(() {
_allResults = data.docs;
print(_allResults);
});
searchResultsList();
return 'complete';
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('TEST CHIP'),
),
drawer: MyMenu(),
backgroundColor: Colors.white,
body: SingleChildScrollView(
child: Container(
alignment: Alignment.center,
padding: EdgeInsets.all(20),
child: Column(
children: <Widget>[
//################################################################################################
// CONTEXT - MultiSelectBottomSheetField with validators
//################################################################################################
MultiSelectBottomSheetField<Contexts>(
key: _multiSelectKeyContext,
initialChildSize: 0.7,
maxChildSize: 0.95,
title: Text("Context"),
buttonText: Text("Context",style: TextStyle(fontSize: 18),),
items: _itemsContext,
searchable: true,
validator: (values) {
if (values == null || values.isEmpty) {
return "";
}
List<String> names = values.map((e) => e.contextName).toList();
return null;
},
onConfirm: (values) {
setState(() {
_selectedContext = values;
});
_multiSelectKeyContext.currentState.validate();
},
chipDisplay: MultiSelectChipDisplay(
onTap: (item) {
setState(() {
_selectedContext.remove(item);
});
_multiSelectKeyContext.currentState.validate();
},
),
),
SizedBox(height: 40),
//################################################################################################
// STATUS - MultiSelectBottomSheetField with validators
//################################################################################################
],
),
],
),
),
),
);
}
}
Model context
import 'package:cloud_firestore/cloud_firestore.dart';
class Contexts {
String id;
String contextName;
Contexts({
this.id,
this.contextName,
});
// formatting for upload to Firebase when creating the trip
Map<String, dynamic> toJson() =>
{
'context_Name': contextName,
};
//creating a Task object from a firebase snapshot
Contexts.fromSnapshot(DocumentSnapshot snapshot) :
id = snapshot.id,
contextName = snapshot['context_Name'];
}