In Android, If I have the information I want to persist across sessions I know I can use SharedPreferences or create a SQLite database or even write a file to the device and read it in later.
Is there a way to save and restore data like this just using Flutter? Or would I need to write device-specific code for Android and iOS like in the services example?
There are a few options:
If you are in a situation where you wanna save a small value that you wanna refer later, then you should store your data as key-value data using shared_preferences
but if you want to store large data you should go with SQLITE
however you can always use firebase database which is available offline
Since we are talking about local storage you can always read and write files to the disk
Other solutions :
A late answer but I hope it will help anyone visiting here later too..
I will provide categories to save and their respective best methods...
You can use shared preferences from flutter's official plugins. https://github.com/flutter/plugins/tree/master/packages/shared_preferences
It uses Shared Preferences for Android, NSUserDefaults for iOS.
You can use Localstorage
flutter pub add localstorage
1- Add dependency to pubspec.yaml (Change the version based on the last)
dependencies:
...
localstorage: ^4.0.0+1
2- Then run the following command
flutter packages get
3- import the localstorage :
import 'package:localstorage/localstorage.dart';
4- create an instance
class MainApp extends StatelessWidget {
final LocalStorage storage = new LocalStorage('localstorage_app');
...
}
Add item to lcoalstorage :
void addItemsToLocalStorage() {
storage.setItem('name', 'Abolfazl');
storage.setItem('family', 'Roshanzamir');
final info = json.encode({'name': 'Darush', 'family': 'Roshanzami'});
storage.setItem('info', info);
}
Get an item from lcoalstorage:
void getitemFromLocalStorage() {
final name = storage.getItem('name'); // Abolfazl
final family = storage.getItem('family'); // Roshanzamir
Map<String, dynamic> info = json.decode(storage.getItem('info'));
final info_name=info['name'];
final info_family=info['family'];
}
Delete an item from localstorage :
void removeItemFromLocalStorage() {
storage.deleteItem('name');
storage.deleteItem('family');
storage.deleteItem('info');
}
If you need to store just simple values like API token or login data (not passwords!), here is what I used:
import 'package:shared_preferences/shared_preferences.dart';
asyncFunc() async { // Async func to handle Futures easier; or use Future.then
SharedPreferences prefs = await SharedPreferences.getInstance();
}
...
// Set
prefs.setString('apiToken', token);
// Get
String token = prefs.getString('apiToken');
// Remove
prefs.remove('apiToken');
Don't forget to add shared_preferences dependency in your pubspec.yaml (preserve spacing format):
dependencies:
shared_preferences: any
I was looking for the same, simple local storage but also with a reasonable level of security. The two solutions I've found that make the most sense are flutter_secure_storage (as mentioned by Raouf) for the small stuff, and hive for larger datasets.
I think If you are going to store large amount of data in local storage you can use sqflite library. It is very easy to setup and I have personally used for some test project and it works fine.
https://github.com/tekartik/sqflite This a tutorial - https://proandroiddev.com/flutter-bookshelf-app-part-2-personal-notes-and-database-integration-a3b47a84c57
If you want to store data in cloud you can use firebase. It is solid service provide by google.
Hive (https://pub.dev/packages/hive) is very fast and flexible solution. But if you have experience with SQL; you can use SqfLite packages (https://pub.dev/packages/sqflite)
