Struct bevy_ecs::event::ManualEventReader

source ·
pub struct ManualEventReader<E: Event> { /* private fields */ }
Expand description

Stores the state for an EventReader.

Access to the Events<E> resource is required to read any incoming events.

In almost all cases, you should just use an EventReader, which will automatically manage the state for you.

However, this type can be useful if you need to manually track events, such as when you’re attempting to send and receive events of the same type in the same system.

§Example

use bevy_ecs::prelude::*;
use bevy_ecs::event::{Event, Events, ManualEventReader};

#[derive(Event, Clone, Debug)]
struct MyEvent;

/// A system that both sends and receives events using a [`Local`] [`ManualEventReader`].
fn send_and_receive_manual_event_reader(
    // The `Local` `SystemParam` stores state inside the system itself, rather than in the world.
    // `ManualEventReader<T>` is the internal state of `EventReader<T>`, which tracks which events have been seen.
    mut local_event_reader: Local<ManualEventReader<MyEvent>>,
    // We can access the `Events` resource mutably, allowing us to both read and write its contents.
    mut events: ResMut<Events<MyEvent>>,
) {
    // We must collect the events to resend, because we can't mutate events while we're iterating over the events.
    let mut events_to_resend = Vec::new();

    for event in local_event_reader.read(&events) {
         events_to_resend.push(event.clone());
    }

    for event in events_to_resend {
        events.send(MyEvent);
    }
}

Implementations§

source§

impl<E: Event> ManualEventReader<E>

source

pub fn read<'a>(&'a mut self, events: &'a Events<E>) -> EventIterator<'a, E>

source

pub fn read_with_id<'a>( &'a mut self, events: &'a Events<E> ) -> EventIteratorWithId<'a, E>

source

pub fn len(&self, events: &Events<E>) -> usize

source

pub fn missed_events(&self, events: &Events<E>) -> usize

Amount of events we missed.

source

pub fn is_empty(&self, events: &Events<E>) -> bool

source

pub fn clear(&mut self, events: &Events<E>)

Trait Implementations§

source§

impl<E: Event> Clone for ManualEventReader<E>

source§

fn clone(&self) -> Self

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
source§

impl<E: Debug + Event> Debug for ManualEventReader<E>

source§

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

Formats the value using the given formatter. Read more
source§

impl<E: Event> Default for ManualEventReader<E>

source§

fn default() -> Self

Returns the “default value” for a type. Read more

Auto Trait Implementations§

§

impl<E> Freeze for ManualEventReader<E>

§

impl<E> RefUnwindSafe for ManualEventReader<E>
where E: RefUnwindSafe,

§

impl<E> Send for ManualEventReader<E>

§

impl<E> Sync for ManualEventReader<E>

§

impl<E> Unpin for ManualEventReader<E>
where E: Unpin,

§

impl<E> UnwindSafe for ManualEventReader<E>
where E: UnwindSafe,

Blanket Implementations§

source§

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

source§

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
source§

impl<T> Borrow<T> for T
where T: ?Sized,

source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
source§

impl<T> BorrowMut<T> for T
where T: ?Sized,

source§

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

Mutably borrows from an owned value. Read more
source§

impl<T> Downcast for T
where T: Any,

source§

fn into_any(self: Box<T>) -> Box<dyn Any>

Convert Box<dyn Trait> (where Trait: Downcast) to Box<dyn Any>. Box<dyn Any> can then be further downcast into Box<ConcreteType> where ConcreteType implements Trait.
source§

fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>

Convert Rc<Trait> (where Trait: Downcast) to Rc<Any>. Rc<Any> can then be further downcast into Rc<ConcreteType> where ConcreteType implements Trait.
source§

fn as_any(&self) -> &(dyn Any + 'static)

Convert &Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &Any’s vtable from &Trait’s.
source§

fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Convert &mut Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &mut Any’s vtable from &mut Trait’s.
source§

impl<T> DowncastSync for T
where T: Any + Send + Sync,

source§

fn into_any_arc(self: Arc<T>) -> Arc<dyn Any + Sync + Send>

Convert Arc<Trait> (where Trait: Downcast) to Arc<Any>. Arc<Any> can then be further downcast into Arc<ConcreteType> where ConcreteType implements Trait.
source§

impl<T> From<T> for T

source§

fn from(t: T) -> T

Returns the argument unchanged.

source§

impl<T> FromWorld for T
where T: Default,

source§

fn from_world(_world: &mut World) -> T

Creates Self using data from the given World.
source§

impl<T> Instrument for T

source§

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

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
source§

fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
source§

impl<T, U> Into<U> for T
where U: From<T>,

source§

fn into(self) -> U

Calls U::from(self).

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

source§

impl<T> ToOwned for T
where T: Clone,

§

type Owned = T

The resulting type after obtaining ownership.
source§

fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
source§

fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
source§

impl<T, U> TryFrom<U> for T
where U: Into<T>,

§

type Error = Infallible

The type returned in the event of a conversion error.
source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
source§

impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

§

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

The type returned in the event of a conversion error.
source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
source§

impl<T> TypeData for T
where T: 'static + Send + Sync + Clone,

source§

impl<T> WithSubscriber for T

source§

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
source§

fn with_current_subscriber(self) -> WithDispatch<Self>

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

impl<T> ConditionalSend for T
where T: Send,