Shared Preferences is a way to store data key-value pair in the Android and iOS.
Table of Contents
shared_preferences
The plugin wraps platform-specific persistent storage for simple data (NSUserDefaults on iOS and macOS, SharedPreferences on Android, etc.)
Example
import 'package:shared_preferences/shared_preferences.dart';
class SharedPrefs {
static Future<SharedPreferences> get prefs => SharedPreferences.getInstance();
static void saveUsername(String username) async{
final p = await prefs;
p.setString('USERNAME', username);
}
static Future<String> loadUsername() async{
final p = await prefs;
return p.getString('USERNAME') ?? 'demo';
}
}Store an object
class User {
final int id;
final String username;
final String fullname;
User(this.id, this.username, this.fullname);
User.fromJson(Map<String, dynamic> json)
: id = json['id'],
username = json['username'],
fullname = json['fullname'];
Map<String, dynamic> toJson() =>
{
'int': int,
'username': username,
'fullname': fullname,
};
}
class UserPrefs {
static Future<SharedPreferences> get prefs => SharedPreferences.getInstance();
static void setUser(User user) async {
final p = await prefs;
p.setString('USER', jsonEncode(user.toJson()));
}
static Future<User> getUser() async {
final p = await prefs;
String userString = p.getString('USER');
return User.fromJson(jsonDecode(userString));
}
}rx_shared_preferences
This is a stream based wrapper over shared_preferences, allowing reactive key-value storage with rxdart Stream observation.
final rxPrefs = RxSharedPreferences(await SharedPreferences.getInstance()); //methods supported to read and save data Future<bool> containsKey(String key); Future<dynamic> get(String key); Future<bool> getBool(String key); Future<double> getDouble(String key); Future<int> getInt(String key); Future<Set<String>> getKeys(); Future<String> getString(String key); Future<List<String>> getStringList(String key); Future<bool> clear(); Future<void> reload(); Future<bool> commit(); Future<bool> remove(String key); Future<bool> setBool(String key, bool value); Future<bool> setDouble(String key, double value); Future<bool> setInt(String key, int value); Future<bool> setString(String key, String value); Future<bool> setStringList(String key, List<String> value);
streaming_shared_preferences
streaming_shared_preferences adds reactive functionality on top of shared_preferences. It can do everything SharedPreferences can, while adding the function of listening to changes in keys.
final preferences = await StreamingSharedPreferences.instance;
// Get a reference to the counter value and provide a default value
// of 0 in case it is null.
Preference<int> counter = preferences.getInt('counter', defaultValue: 0);
// "counter" is a Preference<int> - it can do anything a Stream<int> can.
// We're just going to listen to it and print the value to console.
counter.listen((value) {
print(value);
});
// Somewhere else in your code, update the value.
counter.setValue(1);
// This is exactly same as above, but the above is more convenient.
preferences.setInt('counter', 2);encrypted_shared_preferences
This is the same as Shared Preferences but it saves data as encrypted values. Data is decrypted when retrieved.
EncryptedSharedPreferences encryptedSharedPreferences = EncryptedSharedPreferences();
//read data
encryptedSharedPreferences.getString('username').then((String value) {
print(value);
});
//save data
encryptedSharedPreferences.setString('username', 'admin').then((bool success) {
print(success);
});glutton
Glutton can save data as key-value securely. Stored data is also encrypted.
//save bool isSuccess = await Glutton.eat(key, data); //read dynamic data = await Glutton.vomit(key); //check if data exist bool isExist = await Glutton.have(key); //remove bool isSuccess = await Glutton.digest(key); //clear all await Glutton.flush();
