single_item_shared_prefs

Description:

single item shared prefs

single_item_shared_prefs #
SharedPreferences/UserDefaults persistent Storage implementation.
This package is an addon to the single_item_storage package and offers
a Storage implementation using the shared_preferences package and dart
JSON converters, json.encode and json.decode, to store items.
Getting started #
Create a new instance by providing fromMap and toMap item
converters, itemKey as key for this item in shared preferences,
and an optional sharedPreferences instance.
Storage<User> storage = CachedStorage<User>(SharedPrefsStorage(
itemKey: 'model.user.key',
fromMap: (map) => User.fromMap(map),
toMap: (item) => item.toMap(),
));

@JsonSerializable()
class User {
final String id;
final String email;

factory User.fromMap(Map<String, dynamic> json) => _$UserFromJson(json);
Map<String, dynamic> toMap() => _$UserToJson(this);

User(this.id, this.email);
}
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To store primitive values that don't need a converter use the .primitive named constructor.
/* Supported primitive types:
- bool
- double
- int
- String
- List<String>
*/
SharedPrefsStorage<int>.primitive(itemKey: 'cow_counter')
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If the sharedPreferences is omitted, then SharedPreferences.getInstance is used.
Notice that the SharedPrefsStorage is wrapped in CachedStorage to add in-memory
caching for better performance.
When defining the to/from map converter mind that the map values can only be:
number, boolean, string, null, list or a map with string keys as defined in
json.encode and json.decode from the dart:convert package.
This example uses json_serializable as Map converter for convenience.