Flutter/外部ライブラリ/shared preferences

shared_preferencesをインストール

pubspec.yaml

dependencies:
  flutter:
    sdk: flutter
  shared_preferences: ^0.5.2

flutter packages get

サンプル

import 'package:shared_preferences/shared_preferences.dart';
_incrementCounter() async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  int counter = (prefs.getInt('counter') ?? 0) + 1;
  print('Pressed $counter times.');
  await prefs.setInt('counter', counter);
}

参考

公式：https://pub.dartlang.org/packages/shared_preferences

https://qiita.com/superman9387/items/4786ba4208a546842176