Struct InputEventListener

Wraps around mechanisms for listening in on the InputEvent stream made available through onEvent.

Inherited Members

ValueType.Equals(Object)

ValueType.GetHashCode()

ValueType.ToString()

Namespace: UnityEngine.InputSystem.LowLevel

Syntax

public struct InputEventListener : IObservable<InputEventPtr>

Remarks

This struct can be used to add (Addition(InputEventListener, Action<InputEventPtr, InputDevice>)) or remove (Subtraction(InputEventListener, Action<InputEventPtr, InputDevice>)) callbacks directly to/from the event pipeline.

Alternatively, it can be used as an IObservable to Subscribe(IObserver<InputEventPtr>) observers to the event stream. See Observable for extension methods to set up various observer mechanisms.

InputSystem.onEvent
    .ForDevice(Mouse.current)
    .Call(evt =>
        {
            foreach (var control in evt.EnumerateChangedControls())
                Debug.Log($"Control {control} on mouse has changed value");
        });

Methods

Subscribe(IObserver<InputEventPtr>)

Subscribe an observer to the event pump.

Declaration

public IDisposable Subscribe(IObserver<InputEventPtr> observer)

Parameters

Type	Name	Description
IObserver<InputEventPtr>	observer	Observer to be notified for each event.

Returns

Type	Description
IDisposable	A handle to dispose of the subscription.

Implements

IObservable<T>.Subscribe(IObserver<T>)

Remarks

The easiest way to subscribe is via the extension methods in Observable.

// Subscribe.
var subscription = InputSystem.onEvent.Call(e => Debug.Log("Event"));

// Unsubscribe.
subscription.Dispose();

Operators

Addition(InputEventListener, Action<InputEventPtr, InputDevice>)

Add a delegate to be called for each InputEvent that is processed by the Input System.

Declaration

public static InputEventListener operator +(InputEventListener _, Action<InputEventPtr, InputDevice> callback)

Parameters

Type	Name	Description
InputEventListener	_
Action<InputEventPtr, InputDevice>	callback	A callback to call for each event.

Returns

Type	Description
InputEventListener	The same listener instance.

Remarks

InputSystem.onEvent +=
    (eventPtr, device) =>
    {
        Debug.Log($"Event for {device}");
    };

Exceptions

Type	Condition
ArgumentNullException	callback is null.

See Also

onEvent

Subtraction(InputEventListener, Action<InputEventPtr, InputDevice>)

Remove a delegate from InputEvent.

Declaration

public static InputEventListener operator -(InputEventListener _, Action<InputEventPtr, InputDevice> callback)

Parameters

Type	Name	Description
InputEventListener	_
Action<InputEventPtr, InputDevice>	callback	A callback that was previously installed on onEvent.

Returns

Type	Description
InputEventListener	The same listener instance.

Remarks

InputSystem.onEvent -= myDelegate;

Exceptions

Type	Condition
ArgumentNullException	callback is null.

See Also

onEvent

Extension Methods

Observable.Where<TValue>(IObservable<TValue>, Func<TValue, Boolean>)

Observable.Select<TSource, TResult>(IObservable<TSource>, Func<TSource, TResult>)

Observable.SelectMany<TSource, TResult>(IObservable<TSource>, Func<TSource, IEnumerable<TResult>>)

Observable.Take<TValue>(IObservable<TValue>, Int32)

Observable.ForDevice(IObservable<InputEventPtr>, InputDevice)

Observable.ForDevice<TDevice>(IObservable<InputEventPtr>)

Observable.CallOnce<TValue>(IObservable<TValue>, Action<TValue>)

Observable.Call<TValue>(IObservable<TValue>, Action<TValue>)

See Also

onEvent