Trait Event 

pub trait Event:
    Send
    + Sync
    + 'static {
    type Traversal: Traversal<Self>;

    const AUTO_PROPAGATE: bool = false;

    // Provided methods
    fn register_component_id(world: &mut World) -> ComponentId { ... }
    fn component_id(world: &World) -> Option<ComponentId> { ... }
}

Something that “happens” and might be read / observed by app logic.

Events can be stored in an Events<E> resource You can conveniently access events using the EventReader and EventWriter system parameter.

Events can also be “triggered” on a World, which will then cause any Observer of that trigger to run.

Events must be thread-safe.

Derive

This trait can be derived. Adding auto_propagate sets Self::AUTO_PROPAGATE to true. Adding traversal = "X" sets Self::Traversal to be of type “X”.

use bevy_ecs::prelude::*;

#[derive(Event)]
#[event(auto_propagate)]
struct MyEvent;

Provided Associated Constants

const AUTO_PROPAGATE: bool = false

When true, this event will always attempt to propagate when triggered, without requiring a call to Trigger::propagate.

Required Associated Types

type Traversal: Traversal<Self>

The component that describes which Entity to propagate this event to next, when propagation is enabled.

Provided Methods

fn register_component_id(world: &mut World) -> ComponentId

Generates the ComponentId for this event type.

If this type has already been registered, this will return the existing ComponentId.

This is used by various dynamically typed observer APIs, such as World::trigger_targets_dynamic.

Warning

This method should not be overridden by implementors, and should always correspond to the implementation of component_id.

fn component_id(world: &World) -> Option<ComponentId>

Fetches the ComponentId for this event type, if it has already been generated.

This is used by various dynamically typed observer APIs, such as World::trigger_targets_dynamic.

Warning

This method should not be overridden by implementors, and should always correspond to the implementation of register_component_id.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl Event for GamepadEvent

where GamepadEvent: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for GamepadRumbleRequest

where GamepadRumbleRequest: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for RawGamepadEvent

where RawGamepadEvent: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for AppLifecycle

where AppLifecycle: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for WindowEvent

where WindowEvent: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for ActionRequest

where ActionRequest: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for UntypedAssetLoadFailedEvent

where UntypedAssetLoadFailedEvent: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for GamepadAxisChangedEvent

where GamepadAxisChangedEvent: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for GamepadButtonChangedEvent

where GamepadButtonChangedEvent: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for GamepadButtonStateChangedEvent

where GamepadButtonStateChangedEvent: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for GamepadConnectionEvent

where GamepadConnectionEvent: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for RawGamepadAxisChangedEvent

where RawGamepadAxisChangedEvent: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for RawGamepadButtonChangedEvent

where RawGamepadButtonChangedEvent: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for DoubleTapGesture

where DoubleTapGesture: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for PanGesture

where PanGesture: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for PinchGesture

where PinchGesture: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for RotationGesture

where RotationGesture: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for KeyboardFocusLost

where KeyboardFocusLost: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for KeyboardInput

where KeyboardInput: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for MouseButtonInput

where MouseButtonInput: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for MouseMotion

where MouseMotion: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for MouseWheel

where MouseWheel: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for PointerHits

where PointerHits: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for PointerInput

where PointerInput: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for ReadbackComplete

where ReadbackComplete: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for ScreenshotCaptured

where ScreenshotCaptured: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for SceneInstanceReady

where SceneInstanceReady: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for RequestRedraw

where RequestRedraw: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for WindowBackendScaleFactorChanged

where WindowBackendScaleFactorChanged: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for WindowCloseRequested

where WindowCloseRequested: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for WindowClosed

where WindowClosed: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for WindowClosing

where WindowClosing: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for WindowCreated

where WindowCreated: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for WindowDestroyed

where WindowDestroyed: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for WindowFocused

where WindowFocused: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for WindowOccluded

where WindowOccluded: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for WindowResized

where WindowResized: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for WindowScaleFactorChanged

where WindowScaleFactorChanged: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for WindowThemeChanged

where WindowThemeChanged: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for RawWinitWindowEvent

where RawWinitWindowEvent: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for WakeUp

where WakeUp: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl<A> Event for AssetLoadFailedEvent<A>

where A: Asset, AssetLoadFailedEvent<A>: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl<E> Event for FocusedInput<E>

where E: Event + Clone,

const AUTO_PROPAGATE: bool = true

type Traversal = WindowTraversal

Implementors

impl Event for AppExit

where AppExit: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for FileDragAndDrop

where FileDragAndDrop: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for Ime

where Ime: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for DialogButtonEvent

where Self: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for FormSubmitEvent

where Self: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for RemovedComponentEntity

where RemovedComponentEntity: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for OnDespawn

where OnDespawn: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for CursorEntered

where CursorEntered: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for CursorLeft

where CursorLeft: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for CursorMoved

where CursorMoved: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for OnAdd

where OnAdd: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for OnInsert

where OnInsert: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for OnRemove

where OnRemove: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for OnReplace

where OnReplace: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for TouchInput

where TouchInput: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for WindowMoved

where WindowMoved: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for TextInputChangeEvent

where Self: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl Event for TextInputSubmitEvent

where Self: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl<A> Event for AssetEvent<A>

where A: Asset, AssetEvent<A>: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()

impl<E> Event for Pointer<E>

where E: Debug + Clone + Reflect,

const AUTO_PROPAGATE: bool = true

type Traversal = PointerTraversal

impl<S> Event for StateTransitionEvent<S>

where S: States, StateTransitionEvent<S>: Send + Sync + 'static,

const AUTO_PROPAGATE: bool = false

type Traversal = ()