pub struct Notification { /* private fields */ }
Expand description

A message passed up the tree from a Widget to its ancestors.

In the course of handling an event, a Widget may change some internal state that is of interest to one of its ancestors. In this case, the widget may submit a Notification.

In practice, a Notification is very similar to a Command; the main distinction relates to delivery. Commands are delivered from the root of the tree down towards the target, and this delivery occurs after the originating event call has returned. Notifications are delivered up the tree, and this occurs during event handling; immediately after the child widget’s event method returns, the notification will be delivered to the child’s parent, and then the parent’s parent, until the notification is handled.

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impl Notification

pub fn is<T>(&self, selector: Selector<T>) -> bool

Returns true if self matches this Selector.

pub fn get<T>(&self, selector: Selector<T>) -> Option<&T>where T: Any,

Returns the payload for this Selector, if the selector matches.

Panics

Panics when the payload has a different type, than what the selector is supposed to carry. This can happen when two selectors with different types but the same key are used.

pub fn source(&self) -> WidgetId

The WidgetId of the Widget that sent this Notification.

pub fn warn_if_unused(self, warn_if_unused: bool) -> Notification

Builder-style method to set warn_if_unused.

The default is true.

pub fn warn_if_unused_set(&self) -> bool

Returns whether there should be a warning when no widget handles this notification.

pub fn route(&self) -> WidgetId

The WidgetId of the last Widget that this Notification was passed through.

Example
fn event(&mut self, ctx: &mut EventCtx, event: &Event, data: &mut (), env: &Env) {
    if let Event::Notification(notification) = event {
        if notification.route() == self.widget1.id() {
            // the notification came from inside of widget1
        }
        if notification.route() == self.widget2.id() {
            // the notification came from inside of widget2
        }
    }
}

Trait Implementations§

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impl Clone for Notification

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fn clone(&self) -> Notification

Returns a copy of the value. Read more
1.0.0 · source§

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

Performs copy-assignment from source. Read more
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impl Debug for Notification

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

Formats the value using the given formatter. Read more

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for Twhere T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for Twhere T: ?Sized,

const: unstable · source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided [Span], returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for Twhere U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> Pointable for T

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const ALIGN: usize = mem::align_of::<T>()

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<T> RoundFrom<T> for T

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fn round_from(x: T) -> T

Performs the conversion.
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impl<T, U> RoundInto<U> for Twhere U: RoundFrom<T>,

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fn round_into(self) -> U

Performs the conversion.
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impl<T> Same<T> for T

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type Output = T

Should always be Self
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impl<T> ToOwned for Twhere T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<V, T> VZip<V> for Twhere V: MultiLane<T>,

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fn vzip(self) -> V

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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self> where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a [WithDispatch] wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a [WithDispatch] wrapper. Read more