Enum yew::callback::Callback

pub enum Callback<IN> {
    Callback(Rc<dyn Fn(IN)>),
    CallbackOnce(Rc<RefCell<Option<Box<dyn FnOnce(IN)>>>>),
}

Universal callback wrapper.

Use callbacks carefully, because if you call one from the `update` loop of a `Component` (even from JS) it will delay a message until next. Callbacks should be used from JS callbacks or `setTimeout` calls.

An `Rc` wrapper is used to make it cloneable.

Variants

Callback(Rc<dyn Fn(IN)>)

A callback which can be called multiple times

CallbackOnce(Rc<RefCell<Option<Box<dyn FnOnce(IN)>>>>)

A callback which can only be called once. The callback will panic if it is called more than once.

Implementations

impl<IN> Callback<IN>

pub fn emit(&self, value: IN)

This method calls the callback’s function.

pub fn once<F>(func: F) -> Self where
    F: FnOnce(IN) + 'static, 

Creates a callback from an FnOnce. The programmer is responsible for ensuring that the callback is only called once. If it is called more than once, the callback will panic.

pub fn noop() -> Self

Creates a “no-op” callback which can be used when it is not suitable to use an Option<Callback>.

impl<IN: 'static> Callback<IN>

pub fn reform<F, T>(&self, func: F) -> Callback<T> where
    F: Fn(T) -> IN + 'static, 

Changes the input type of the callback to another. Works like the map method but in the opposite direction.

Trait Implementations

impl<IN> Clone for Callback<IN>

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<IN> Debug for Callback<IN>

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

Formats the value using the given formatter.

impl<IN> Default for Callback<IN>

fn default() -> Self

Returns the “default value” for a type.

impl<IN, F: Fn(IN) + 'static> From<F> for Callback<IN>

fn from(func: F) -> Self

Performs the conversion.

impl<IN> PartialEq<Callback<IN>> for Callback<IN>

fn eq(&self, other: &Callback<IN>) -> bool

This method tests for self and other values to be equal, and is used by ==.

#[must_use]

fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl<T> ImplicitClone for Callback<T>