Added a way to subscribe to input events from a poco class (#380)

XRTK-Core/Packages/com.xrtk.core/Interfaces/InputSystem/IMixedRealityInputSystem.cs

@@ -7,6 +7,7 @@
 using XRTK.Definitions.Devices;
 using XRTK.Definitions.InputSystem;
 using XRTK.Definitions.Utilities;
+using XRTK.EventDatum.Input;
 using XRTK.Interfaces.Providers.Controllers;
 using XRTK.Interfaces.Events;
 
@@ -122,6 +123,15 @@ public interface IMixedRealityInputSystem : IMixedRealityEventSystem
 
         #region Input Events
 
+        /// <summary>
+        /// Raised when an input event is triggered.
+        /// </summary>
+        /// <remarks>
+        /// WARNING: This event should not be subscribed to by MonoBehaviours!
+        /// Use the InputHandler interfaces instead.
+        /// </remarks>
+        event Action<BaseInputEventData> OnInputEvent;
+
         #region Input Source Events
 
         /// <summary>

XRTK-Core/Packages/com.xrtk.core/Services/InputSystem/MixedRealityInputSystem.cs

@@ -233,6 +233,11 @@ public override void HandleEvent<T>(BaseEventData eventData, ExecuteEvents.Event
                 return;
             }
 
+            // Sent the event to any POCO classes that have subscribed for events.
+            // WARNING: This event should not be subscribed to by MonoBehaviours!
+            // Use the InputHandler interfaces instead.
+            OnInputEvent?.Invoke(baseInputEventData);
+
             // Send the event to global listeners
             base.HandleEvent(eventData, eventHandler);
 
@@ -476,7 +481,7 @@ public void ClearFallbackInputStack()
         /// <inheritdoc />
         public bool TryGetController(IMixedRealityInputSource inputSource, out IMixedRealityController controller)
         {
-            foreach (IMixedRealityController mixedRealityController in DetectedControllers)
+            foreach (var mixedRealityController in DetectedControllers)
             {
                 if (inputSource.SourceId == mixedRealityController.InputSource.SourceId)
                 {
@@ -493,6 +498,9 @@ public bool TryGetController(IMixedRealityInputSource inputSource, out IMixedRea
 
         #region Input Events
 
+        /// <inheritdoc />
+        public event Action<BaseInputEventData> OnInputEvent;
+
         #region Input Source Events
 
         /// <inheritdoc />