PrfJson<T> class

A cached preference object specialized for storing JSON-serializable objects.

This class provides type-safe access to complex objects stored in SharedPreferences by serializing them to JSON. It uses in-memory caching for improved performance and requires conversion functions to translate between the object type and JSON.

Example:

class User {
  final String name;
  final int age;

  User({required this.name, required this.age});

  factory User.fromJson(Map<String, dynamic> json) => User(
    name: json['name'],
    age: json['age'],
  );

  Map<String, dynamic> toJson() => {
    'name': name,
    'age': age,
  };
}

final userPreference = PrfJson<User>(
  'current_user',
  fromJson: User.fromJson,
  toJson: (user) => user.toJson(),
);

await userPreference.set(User(name: 'Alice', age: 30));
final user = await userPreference.get();
Inheritance
Available extensions

Constructors

PrfJson.new(String key, {required T fromJson(Map<String, dynamic> json), required Map<String, dynamic> toJson(T object), T? defaultValue})
Creates a new cached JSON preference.

Properties

adapter → PrfAdapter<T>
Gets the adapter used to convert between the object and its JSON representation.
no setteroverride
cachedValue → T?
Returns the currently cached value without accessing SharedPreferences.
no setterinherited
defaultValue → T?
Optional default value to use when no value exists for key.
finalinherited
hashCode → int
The hash code for this object.
no setterinherited
key → String
The key used to store this preference in SharedPreferences.
finalinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

existsOnPrefs() → Future<bool>

Available on BasePrfObject<T>, provided by the PrfOperationExtensions extension

Checks if the key exists in the default PrfService instance.
get() → Future<T?>

Available on BasePrfObject<T>, provided by the PrfOperationExtensions extension

Gets the value from the default PrfService instance.
getOrFallback(T fallback) → Future<T>

Available on BasePrfObject<T>, provided by the PrfOperationExtensions extension

Gets the value or returns the provided fallback if the value is null.
getValue(SharedPreferencesAsync prefs) → Future<T?>
Gets the value, using the cached value if available or reading from storage if not.
inherited
initCache(SharedPreferencesAsync prefs) → Future<void>
Initializes the cache by reading the current value from SharedPreferences.
inherited
isNull() → Future<bool>

Available on BasePrfObject<T>, provided by the PrfOperationExtensions extension

Checks if the value is null in the default PrfService instance.
isValueNull(SharedPreferencesAsync prefs) → Future<bool>
Checks if the stored value is null.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
remove() → Future<void>

Available on BasePrfObject<T>, provided by the PrfOperationExtensions extension

Removes the value from the default PrfService instance.
removeValue(SharedPreferencesAsync prefs) → Future<void>
Removes the value from SharedPreferences and clears the cached value.
inherited
set(T value) → Future<void>

Available on BasePrfObject<T>, provided by the PrfOperationExtensions extension

Sets the value using the default PrfService instance.
setValue(SharedPreferencesAsync prefs, T value) → Future<void>
Stores value in SharedPreferences and updates the cached value.
inherited
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited