Flutter : sort multidimensional array List - arrays

Question

I'm trying to adapt some code to sort on a multidimensional array.
But I can't recreate the filtered array to retrieve the sets of elements.
Here is the original code:
import 'package:flutter/material.dart';
class TestPage extends StatefulWidget {
#override
_TestPageState createState() => _TestPageState();
}
class _TestPageState extends State<TestPage> {
TextEditingController _textController = TextEditingController();
List<String> initialList = ["Chat", "Chien", "Rat", "Cheval", "Ours"];
List<String> filteredList = List();
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text('Test search')),
body: Column(
children: <Widget>[
TextField(
controller: _textController,
onChanged: (text) {
text = text.toLowerCase();
setState(() {
filteredList = initialList
.where((element) => element.toLowerCase().contains(text))
.toList();
});
},
),
if (filteredList.length == 0 && _textController.text.isEmpty)
Expanded(
child: ListView.builder(
itemCount: initialList.length,
itemBuilder: (BuildContext context, index) {
return Container(
height: 50,
child: Text(initialList[index]),
);
}))
else if (filteredList.length==0 && _textController.text.isNotEmpty)
Expanded(
child: Container(
child: Text('Aucune donnée'),
),
)
else
Expanded(
child: ListView.builder(
itemCount: filteredList.length,
itemBuilder: (BuildContext context, index) {
return Container(
height: 50,
child: Text(filteredList[index]),
);
}),
),
],
));
}
}
And my modified code:
import 'package:flutter/material.dart';
class Houblons extends StatefulWidget {
#override
_HoublonsState createState() => _HoublonsState();
}
class _HoublonsState extends State<Houblons> {
TextEditingController _textController = TextEditingController();
//List<String> initialList = ["Chat", "Chien", "Rat", "Cheval", "Ours"];
List<ListeElements> initialList = [
new ListeElements (nom : "testa", lienp: 1),
new ListeElements (nom : "testaa", lienp: 2),
new ListeElements (nom : "testaa b", lienp: 2),
new ListeElements (nom : "testaa bb", lienp: 2),
new ListeElements (nom : "testaa bb c", lienp: 2),
];
List<ListeElements2> filteredList = List();
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text('Houblons')),
body: Column(
children: <Widget>[
TextField(
controller: _textController,
onChanged: (text) {
text = text.toLowerCase();
setState(() {
filteredList = initialList
.where((element) => element.nom.contains(text)).cast<String>()
.toList();
});
},
decoration: new InputDecoration(
labelText: "Champ de recherche",
),
),
if (filteredList.length == 0 && _textController.text.isEmpty)
Expanded(
child: ListView.builder(
itemCount: initialList.length,
itemBuilder: (BuildContext context, index) {
return Container(
height: 50,
child: Text(initialList[index].nom),
);
}))else if (filteredList.length==0 && _textController.text.isNotEmpty)
Expanded(
child: Container(
child: Text('Aucune donnée'),
),
)else
Expanded(
child: ListView.builder(
itemCount: filteredList.length,
itemBuilder: (BuildContext context, index) {
return Container(
height: 50,
child: Text(filteredList[index].nom),
);
}),
),
],
));
}
}
class ListeElements {
String nom;
int lienp;
ListeElements({String nom, int lienp}){
this.nom = nom;
this.lienp = lienp;
}
}
class ListeElements2 {
String nom;
int lienp;
ListeElements2({String nom, int lienp}){
this.nom = nom;
this.lienp = lienp;
}
}
I planned after to make a listview with a link on each element which will display an alert with elements coming from the multidimensional table.
Thank you for your help.
Thanks, but I can't.
I found some code that works with a json list from an online list, but when that created the list its not working.
I can't find the mistake I'm making,
Yet I think it's simple but I'm blocking.
I can't find an example code online
The original code:
a link!
here is my code:
import 'dart:async';
import 'dart:convert';
import 'package:http/http.dart' as http;
class TestFilter extends StatefulWidget {
TestFilter() : super();
final String title = "Filter List Demo";
#override
TestFilterState createState() => TestFilterState();
}
class Debouncer {
final int milliseconds;
VoidCallback action;
Timer _timer;
Debouncer({this.milliseconds});
run(VoidCallback action) {
if (null != _timer) {
_timer.cancel();
}
_timer = Timer(Duration(milliseconds: milliseconds), action);
}
}
class TestFilterState extends State<TestFilter> {
final _debouncer = Debouncer(milliseconds: 500);
List<User> filteredUsers = List();
List<User> users = [
{'id': 40, 'name': "moia", 'email': "test#1.com"},
{'id': 40, 'name': "moiaa", 'email': "test#2.com"},
{'id': 40, 'name': "moiab", 'email': "test#3.com"},
];
#override
void initState() {
super.initState();
setState(() {
users = filteredUsers;
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Column(
children: <Widget>[
TextField(
decoration: InputDecoration(
contentPadding: EdgeInsets.all(15.0),
hintText: 'Filter by name or email',
),
onChanged: (string) {
_debouncer.run(() {
setState(() {
filteredUsers = users
.where((u) => (u.name
.toLowerCase()
.contains(string.toLowerCase()) ||
u.email.toLowerCase().contains(string.toLowerCase())))
.toList();
});
});
},
),
Expanded(
child: ListView.builder(
padding: EdgeInsets.all(10.0),
itemCount: filteredUsers.length,
itemBuilder: (BuildContext context, int index) {
return Card(
child: Padding(
padding: EdgeInsets.all(10.0),
child: Column(
mainAxisAlignment: MainAxisAlignment.start,
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Text(
filteredUsers[index].name,
style: TextStyle(
fontSize: 16.0,
color: Colors.black,
),
),
SizedBox(
height: 5.0,
),
Text(
filteredUsers[index].email.toLowerCase(),
style: TextStyle(
fontSize: 14.0,
color: Colors.grey,
),
),
],
),
),
);
},
),
),
],
),
);
}
}
class User {
int id;
String name;
String email;
User({this.id, this.name, this.email});
factory User.fromJson(Map<String, dynamic> json) {
return User(
id: json["id"] as int,
name: json["name"] as String,
email: json["email"] as String,
);
}
}

Answer 1

Are you sorting the List ascending/descending? List.sort() can be applied to multidimensional array/List.
This sorts the name in ascending order
filteredUsers = users.sort((a, b) =>
a.name.toLowerCase().compareTo(b.name.toLowerCase()));
For descending, you just need to swap a and b
filteredUsers = users.sort((b, a) =>
a.name.toLowerCase().compareTo(b.name.toLowerCase()));
I've also tested out the filter that you've applied on the List. The filter works without issues. The issue here is that you're adding incompatible type to List<User>. Changing it to List works without issues.
List users = [
{'id': 40, 'name': "moia", 'email': "test#1.com"},
{'id': 40, 'name': "moiaa", 'email': "test#2.com"},
{'id': 40, 'name': "moiab", 'email': "test#3.com"},
];
String keyword = 'moiaa';
filtered = users.where((a) => a['name'].contains(keyword.toLowerCase()) ||
a['email'].toLowerCase().contains(keyword.toLowerCase())).toList();
print(filtered);
The output should print [{id: 40, name: moiaa, email: test#2.com}]
If you'd like to use the User object in the List as List<User>. The List items should be added using the constructor.
List<User> users = [
User(id: 40, name: "moia", email: "test#1.com"),
User(id: 40, name: "moiaa", email: "test#2.com"),
User(id: 40, name: "moiab", email: "test#3.com"),
];
String keyword = 'moiaa';
filtered = users.where((a) => a.name.contains(keyword.toLowerCase()) ||
a.email.toLowerCase().contains(keyword.toLowerCase())).toList();
for(User user in filtered){
print('id: ${user.id} name: ${user.name} email: ${user.email}');
}
The output should print: id: 40 name: moiaa email: test#2.com