Base class for using shared/local preferences in Flutter

base_prefs.dart

abstract class BasePrefs {
  Future<void> initialise();

  //Getters
  bool getBool(String key);

  int getInt(String key);

  double getDouble(String key);

  String getString(String key);

  List<String> getStringList(String key);

  //Setters
  void setBool(String key, bool value);

  void setInt(String key, int value);

  void setDouble(String key, double value);

  void setString(String key, String value);

  void setStringList(String key, List<String> value);

  //MISC
  Future<void> reload();

  void remove(String key);

  void clear();
}

json_prefs.dart

import 'package:localstorage/localstorage.dart';
import 'package:workozy_app/data/local/prefs/base_prefs.dart';

class JsonPrefs extends BasePrefs {
  final _storage = LocalStorage('workozy_prefs');

  @override
  Future<void> initialise() async {
    print("Initialising Json Prefs...");
    var result = await _storage.ready;
    if (result != true) {
      throw Exception("Error in initialising json_prefs");
    }
  }

  @override
  bool getBool(String key) {
    return _storage.getItem(key) as bool;
  }

  @override
  double getDouble(String key) {
    return _storage.getItem(key) as double;
  }

  @override
  int getInt(String key) {
    return _storage.getItem(key) as int;
  }

  @override
  String getString(String key) {
    return _storage.getItem(key) as String;
  }

  @override
  List<String> getStringList(String key) {
    return ((_storage.getItem(key) as List) ?? []).cast<String>();
  }

  @override
  void clear() {
    _storage.clear();
  }

  @override
  Future<void> reload() async {
    // TODO: implement reload
  }

  @override
  void remove(String key) {
    _storage.deleteItem(key);
  }

  @override
  void setBool(String key, bool value) {
    _storage.setItem(key, value);
  }

  @override
  void setDouble(String key, double value) {
    _storage.setItem(key, value);
  }

  @override
  void setInt(String key, int value) {
    _storage.setItem(key, value);
  }

  @override
  void setString(String key, String value) {
    _storage.setItem(key, value);
  }

  @override
  void setStringList(String key, List<String> value) {
    _storage.setItem(key, value);
  }
}