Struct ValueNotifier 

pub struct ValueNotifier<T> { /* private fields */ }

A notifier that holds a value, and tells its listeners when the value changes.

Cloning gives another handle to the same value.

Implementations

impl<T> ValueNotifier<T>

where T: 'static,

pub fn new(value: T) -> ValueNotifier<T>

A notifier holding value.

pub fn get(&self) -> T

where T: Clone,

A copy of the value.

pub fn with<R>(&self, read: impl FnOnce(&T) -> R) -> R

Reads the value without copying it.

pub fn set(&self, value: T)

where T: PartialEq,

Replaces the value, and notifies — unless it is the value already there, in which case nothing changed and nobody is told.

pub fn update(&self, change: impl FnOnce(&mut T))

Changes the value in place, and notifies.

Trait Implementations

impl<T> Clone for ValueNotifier<T>

fn clone(&self) -> ValueNotifier<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T> Debug for ValueNotifier<T>

where T: Debug,

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<T> Default for ValueNotifier<T>

where T: Default + 'static,

fn default() -> ValueNotifier<T>

Returns the “default value” for a type.

impl<T> Listenable for ValueNotifier<T>

fn add_listener(&self, listener: impl Fn() + 'static) -> Subscription

Calls listener whenever this changes, until the returned Subscription is dropped.