flutter: doesn't embed data from function to list - list

Question

I want to create a list, those people location = "Barishal". That's why, I created a function and try to push data ( which data I obtained from getSpecific() function ) to a new list ( myList ). But It created a problem ....
here is my code-
class BookData extends ChangeNotifier {
List<MyModel> data = [
MyModel(name: "Abir", location: "Dhaka"),
MyModel(name: "Shuvro", location: "Barishal"),
MyModel(name: "Anik", location: "Barishal")
];
List<MyModel> get getMydata{
return data;
}
getSpecific (){
for(int i=0;i<data.length;i++){
if(data[i].location=="Barishal"){
print(data[i]);
return data[i];
}
}
}
List myList = getSpecific();
}
How can I fix this problem ?

Answer 1

You can copy paste run full code below
You can provide search string and use UnmodifiableListView<MyModel> and filter with _myData.where
code snippet
class BookData extends ChangeNotifier {
final List<MyModel> _myData = [
MyModel(name: "Abir", location: "Dhaka"),
MyModel(name: "Shuvro", location: "Barishal"),
MyModel(name: "Anik", location: "Barishal")
];
String _searchString = "";
UnmodifiableListView<MyModel> get books => _searchString.isEmpty
? UnmodifiableListView(_myData)
: UnmodifiableListView(
_myData.where((dog) => dog.location.contains(_searchString)));
void getSpecific(String searchString) {
_searchString = searchString;
print(_searchString);
notifyListeners();
}
}
working demo
full code
import 'package:flutter/material.dart';
import 'package:flutter/cupertino.dart';
import 'dart:collection';
import 'package:provider/provider.dart';
class BookData extends ChangeNotifier {
final List<MyModel> _myData = [
MyModel(name: "Abir", location: "Dhaka"),
MyModel(name: "Shuvro", location: "Barishal"),
MyModel(name: "Anik", location: "Barishal")
];
String _searchString = "";
UnmodifiableListView<MyModel> get books => _searchString.isEmpty
? UnmodifiableListView(_myData)
: UnmodifiableListView(
_myData.where((dog) => dog.location.contains(_searchString)));
void getSpecific(String searchString) {
_searchString = searchString;
print(_searchString);
notifyListeners();
}
}
class MyModel {
final String name;
final String location;
MyModel({this.name, this.location});
}
void main() {
runApp(
ChangeNotifierProvider(
create: (context) => BookData(),
child: MyApp(),
),
);
}
class MyApp extends StatefulWidget {
#override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
final _controller = TextEditingController();
String _searchText;
#override
void initState() {
_controller.addListener(
() {
setState(() {
_searchText = _controller.text;
});
},
);
super.initState();
}
#override
void dispose() {
_controller.dispose();
super.dispose();
}
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Example',
home: Scaffold(
appBar: AppBar(
title: Text('Example'),
),
body: Column(
mainAxisAlignment: MainAxisAlignment.start,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
TextField(
controller: _controller,
decoration: InputDecoration(
hintText: "Search",
prefixIcon: Icon(Icons.search),
border: OutlineInputBorder(
borderRadius: BorderRadius.all(
Radius.circular(4.0),
),
),
),
onChanged: (value) {
Provider.of<BookData>(context, listen: false)
.getSpecific(value);
},
),
Consumer<BookData>(builder: (context, bookData, child) {
print(bookData.books.toString());
return Expanded(
child: ListView.builder(
shrinkWrap: true,
itemCount: bookData.books.length,
itemBuilder: (context, index) => Card(
elevation: 3,
child: ListTile(
title: Text(bookData.books[index].name),
),
)),
);
}),
],
),
),
);
}
}

Answer 2

When you need to filter a list, you can use the where method.
Here's a simple example.
List<MyModel> myNewList = data.where((item) => item.location == "Barishal").toList();
Anyway, your code seems to be returning just the first item, not a list.

Answer 3

I fixed your code like below
List<MyModel> getSpecific (){
List<MyModel> result = [];
for(int i=0;i<data.length;i++){
if(data[i].location=="Barishal"){
print(data[i]);
result.add(data[i]);
}
}
return result;
}