Shared Preferences is a key-value store that is used to persist data in a Flutter application between app launches. To use Shared Preferences in Flutter, you need to use the shared_preferences
package.
Here’s an example of how you could use Shared Preferences to keep a user logged in:
- Add the
shared_preferences
package to yourpubspec.yaml
file:
dependencies:
shared_preferences: ^0.5.12
2. Import the shared_preferences
package in your Dart code:
import 'package:shared_preferences/shared_preferences.dart';
3. To store the user’s login state, you could use the setBool
method to set a value of true
or false
in Shared Preferences:
Future<void> setUserLoggedIn(bool value) async {
final prefs = await SharedPreferences.getInstance();
prefs.setBool('loggedIn', value);
}
4. To retrieve the user’s login state, you could use the getBool
method to retrieve the value of 'loggedIn'
from Shared Preferences:
Future<bool> isUserLoggedIn() async {
final prefs = await SharedPreferences.getInstance();
return prefs.getBool('loggedIn') ?? false;
}
5. Finally, you can use these methods in your Flutter app to keep the user logged in. For example, when the user logs in, you can call the setUserLoggedIn
method with a value of true
, and when the user logs out, you can call it with a value of false
. When your app starts, you can call the isUserLoggedIn
method to check if the user is logged in, and if so, redirect them to the appropriate page.