What is SharedPreferences in Flutter?

SharedPreferences is a simple plugin for storing small amounts of data in key-value format on the user's device. It is based on NSUserDefaults in iOS and SharedPreferences in Android.

It is used for storing:

• User settings (e.g., theme, language)
• Small session data (e.g., login status)

Pros:

• Easy to use
• Suitable for small data

Cons:

• Inefficient for large data volumes
• Not suitable for storing structured data (e.g., databases)

Example usage:

import 'package:shared_preferences/shared_preferences.dart';

Future<void> saveData() async {
  final prefs = await SharedPreferences.getInstance();
  await prefs.setInt('counter', 10);
  await prefs.setString('username', 'FlutterUser');
}

Future<int?> readIntData() async {
  final prefs = await SharedPreferences.getInstance();
  return prefs.getInt('counter');
}