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>
impl<E: Event> ManualEventReader<E>
sourcepub fn read<'a>(&'a mut self, events: &'a Events<E>) -> EventIterator<'a, E> ⓘ
pub fn read<'a>(&'a mut self, events: &'a Events<E>) -> EventIterator<'a, E> ⓘ
sourcepub fn read_with_id<'a>(
&'a mut self,
events: &'a Events<E>
) -> EventIteratorWithId<'a, E> ⓘ
pub fn read_with_id<'a>( &'a mut self, events: &'a Events<E> ) -> EventIteratorWithId<'a, E> ⓘ
sourcepub fn len(&self, events: &Events<E>) -> usize
pub fn len(&self, events: &Events<E>) -> usize
See EventReader::len
sourcepub fn missed_events(&self, events: &Events<E>) -> usize
pub fn missed_events(&self, events: &Events<E>) -> usize
Amount of events we missed.
Trait Implementations§
source§impl<E: Event> Clone for ManualEventReader<E>
impl<E: Event> Clone for ManualEventReader<E>
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> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
source§impl<T> Downcast for Twhere
T: Any,
impl<T> Downcast for Twhere
T: Any,
source§fn into_any(self: Box<T>) -> Box<dyn Any>
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>
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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)
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)
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
impl<T> DowncastSync for T
source§impl<T> FromWorld for Twhere
T: Default,
impl<T> FromWorld for Twhere
T: Default,
source§fn from_world(_world: &mut World) -> T
fn from_world(_world: &mut World) -> T
Creates
Self
using data from the given World
.