
This article is about making a filter/search ListView in Flutter. We will take a quick look at the approach to get the job done and then go through a concrete and complete example of applying that approach. No third-party packages are required.
Overview
We will create a function to filter the results, and this function will be called when the text field changes (onChanged). The search algorithm can be different on a case-by-case basis, but the simplest and most popular is to use the following Dart methods:
- where(): Returns a new lazy Iterable with all elements that satisfy one or many conditions.
- contains(): Used to determine whether a string contains another string (you can try other string methods like startsWith(), endsWith(), etc.)
- toLowerCase(): This string method will convert all characters in this string to lowercase so that it doesn’t matter whether the search keyword is uppercase or lowercase.
These words can be confusing. See the example for more clarity.
Example
Let’s say we have a list of users with some information, including id, name, and age. In the beginning, all of these users are shown in a ListView. If you type something into the search field, only users whose names match the keyword will be displayed. If you clear the search field, the full list of users will appear again.
Preview
The Code
The full source code in lib/main.dart with explanations in the comments (this code was updated to work properly with the latest version of Flutter):
// main.dart
import 'package:flutter/material.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
return const MaterialApp(
// Remove the debug banner
debugShowCheckedModeBanner: false,
title: 'Kindacode.com',
home: HomePage(),
);
}
}
class HomePage extends StatefulWidget {
const HomePage({Key? key}) : super(key: key);
@override
State<HomePage> createState() => _HomePageState();
}
class _HomePageState extends State<HomePage> {
// This holds a list of fiction users
// You can use data fetched from a database or a server as well
final List<Map<String, dynamic>> _allUsers = [
{"id": 1, "name": "Andy", "age": 29},
{"id": 2, "name": "Aragon", "age": 40},
{"id": 3, "name": "Bob", "age": 5},
{"id": 4, "name": "Barbara", "age": 35},
{"id": 5, "name": "Candy", "age": 21},
{"id": 6, "name": "Colin", "age": 55},
{"id": 7, "name": "Audra", "age": 30},
{"id": 8, "name": "Banana", "age": 14},
{"id": 9, "name": "Caversky", "age": 100},
{"id": 10, "name": "Becky", "age": 32},
];
// This list holds the data for the list view
List<Map<String, dynamic>> _foundUsers = [];
@override
initState() {
// at the beginning, all users are shown
_foundUsers = _allUsers;
super.initState();
}
// This function is called whenever the text field changes
void _runFilter(String enteredKeyword) {
List<Map<String, dynamic>> results = [];
if (enteredKeyword.isEmpty) {
// if the search field is empty or only contains white-space, we'll display all users
results = _allUsers;
} else {
results = _allUsers
.where((user) =>
user["name"].toLowerCase().contains(enteredKeyword.toLowerCase()))
.toList();
// we use the toLowerCase() method to make it case-insensitive
}
// Refresh the UI
setState(() {
_foundUsers = results;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Kindacode.com'),
),
body: Padding(
padding: const EdgeInsets.all(10),
child: Column(
children: [
const SizedBox(
height: 20,
),
TextField(
onChanged: (value) => _runFilter(value),
decoration: const InputDecoration(
labelText: 'Search', suffixIcon: Icon(Icons.search)),
),
const SizedBox(
height: 20,
),
Expanded(
child: _foundUsers.isNotEmpty
? ListView.builder(
itemCount: _foundUsers.length,
itemBuilder: (context, index) => Card(
key: ValueKey(_foundUsers[index]["id"]),
color: Colors.amberAccent,
elevation: 4,
margin: const EdgeInsets.symmetric(vertical: 10),
child: ListTile(
leading: Text(
_foundUsers[index]["id"].toString(),
style: const TextStyle(fontSize: 24),
),
title: Text(_foundUsers[index]['name']),
subtitle: Text(
'${_foundUsers[index]["age"].toString()} years old'),
),
),
)
: const Text(
'No results found',
style: TextStyle(fontSize: 24),
),
),
],
),
),
);
}
}
Actually, we don’t need a TextEditingController in this case.
Conclusion
You’ve learned how to create a filter/search ListView in Flutter. At this point, you should get a better understanding and become more comfortable when dealing with this task or something similar to it. Continue exploring list view and other interesting stuff by taking a look at the following articles:
- Working with ReorderableListView in Flutter
- Flutter SliverList – Tutorial and Example
- Flutter AnimatedList – Tutorial and Examples
- Flutter & Hive Database: CRUD Example
- Flutter and Firestore Database: CRUD example
- Flutter + Firebase Storage: Upload, Retrieve, and Delete files
- Flutter: Creating a Fullscreen Modal with Search Form
You can also check out our Flutter topic page or Dart topic page for the latest tutorials and examples.
Schön, aber wie integriere ich meine sqflite Datenbank?
You can see this article: Flutter & SQLite: CRUD Example (updated).
how to add mysql database
Schön, aber wie integriere ich meine sqflite Datenbank?
Thanks
great
i want to add filter in tab bar view.how it is possible
hello, Thanks for your tutorial, it’s great! I tried by creating a Map like: (word) – (translated word) and an option button to display the list either (word – translated word) or (translated word – word) but in the display (translated word – word) the result is no longer sorted… Read more »
Hi, Good Man: Flutter Hive CRUD should go one more step to include Search, making it CRUDS, which I have just done with your guide, and happy with it.
Great! Good Man. Thanks for your kindness.
Happy coding, man
source code please
How do we apply to Api
There are 2 common approaches:
+ Load all data and filter them in your Flutter app (if you have a limited amount of data)
+ Send search params to your backend and filter the results on your sever-side
gracias
eres bienvenido
Sir, can I ask you this one question? Ummm is there any way that I can add the filter to this searching system?
Do you mean a detailed search system? Yes, you can, but it may need some extra work.
Спасибо!
You’re welcome
tank you bro
Genial..!!!
Thank you
you are the best <3
Thank you! I am a beginner and have looked for this example.
As always, thank you.