Flutter Local Storage

tip

Package: https://pub.dev/packages/shared_preferences

note

Implementation Date: Jul/23

Version: 2.2.0

Description Methods

• Load an item;
• Save an item;
• Remove an item;
• Load Many items;
• Save Many items;

Abstract Class

abstract class ILocalStorage {
  Future<dynamic> load({required String key});
  Future<bool> save({required String key, required value});
  Future<bool> remove({required String key});
  Future<List<String>?> loadMany({required String infoKey});
  Future<bool> saveMany(
      {required String infoKey, required List<String> dataList});
}

Implementation Class

class LocalSharedPreferences implements ILocalStorage {
  const LocalSharedPreferences();
  @override
  Future<dynamic> load({required String key}) async {
    final sharedPreferences = await SharedPreferences.getInstance();
    if (sharedPreferences.containsKey(key)) {
      final doc = sharedPreferences.get(key);
      return doc;
    } else {
      return null;
    }
  }

  @override
  Future<List<String>?> loadMany({required String infoKey}) async {
    final sharedPreferences = await SharedPreferences.getInstance();

    List<dynamic>? list = sharedPreferences.getStringList(infoKey);
    if (list != null && list is List<String>) {
      list = list.cast<String>().toList();
      return list.toList();
    } else {
      return null;
    }
  }

  @override
  Future<bool> save({required String key, required value}) async {
    final sharedPreferences = await SharedPreferences.getInstance();
    if (value is String) {
      return sharedPreferences.setString(key, value);
    } else if (value is bool) {
      return sharedPreferences.setBool(key, value);
    } else if (value is int) {
      return sharedPreferences.setInt(key, value);
    } else if (value is double) {
      return sharedPreferences.setDouble(key, value);
    } else if (value is List<String>) {
      return sharedPreferences.setStringList(key, value);
    }
    throw Exception('Value type (${value.runtimeType}) not valid');
  }

  @override
  Future<bool> saveMany({required String infoKey, required List<String> dataList}) async {
    final sharedPreferences = await SharedPreferences.getInstance();
    return sharedPreferences.setStringList(infoKey, dataList);
  }

  @override
  Future<bool> remove({required String key}) async {
    try {
      final sharedPreferences = await SharedPreferences.getInstance();
      sharedPreferences.remove(key);
      return true;
    } catch (e) {
      log(e.toString());
      log(StackTrace.current.toString());
      return false;
    }
  }
}

danger

Contributor: BrAcInhO