List data Disappears after pressing back Flutter - list

Question

Whenever I add an item to my least it adds to the list at the current state but when I reopen after pop context the item is no more there
*How can I have the items in list permanently *enter image description hereenter image description hereenter image description hereenter image description hereenter image description here
class Prabesh extends StatefulWidget {
#override
_PrabeshState createState() => _PrabeshState();
}
class _PrabeshState extends State<Prabesh> {
final List users = [
'Ram',
'Shyam',
'Hari',
'Paudel',
'Pandey',
'Sashwat',
'Kismat',
];
// ondlt(Key key) {
// for (int i = 0; i <= users.length; i++) {
// var a = users.elementAt(i);
// if (key == a.key) {
// users.removeAt(i);
// }
// }
// }
void onClk() {
myDialog(BuildContext, context);
}
final myUser = TextEditingController();
myDialog(BuildContext, context) {
showDialog(
barrierDismissible: false,
context: context,
builder: (context) {
return AlertDialog(
title: Text('Add a user'),
content: TextFormField(
controller: myUser,
maxLength: 20,
decoration: InputDecoration(
hintText: 'Enter Username',
),
),
actions: [
ElevatedButton(
onPressed: () => Navigator.pop(context),
child: Text('Cancel')),
ElevatedButton(
onPressed: () {
setState(() {
if (myUser.text.isEmpty) {
return Navigator.pop(context);
} else {
users.add(myUser.text);
return Navigator.pop(context);
}
});
},
child: Text('Add'),
),
],
);
});
}
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: Text('Prabesh'),
leading: BackButton(
onPressed: () => Navigator.pop(context),
),
),
body: ListView.builder(
itemCount: users.length,
itemBuilder: (context, index) {
return Card(
elevation: 10,
child: ListTile(
// key: Key(users[index]),
//onLongPress: () => ondlt(key),
onTap: () {},
title: Text(users[index]),
trailing: Icon(Icons.menu),
leading: CircleAvatar(
child: Text(users[index].substring(0, 1)),
),
),
);
},
),
floatingActionButton: FloatingActionButton(
onPressed: () => onClk(),
child: Icon(Icons.add),
),
),
);
}
}

Answer 1

You must save your data locally or on an online database.
For saving data on mobile storage you can use this package.
But for saving data on an online database you can use Firebase or you must develop a web server.