Why TrackAsset.CreateMark not trigger MarkEditor.OnCreate?

Unity Engine
, , , ,
1

I’m learning about Unity’s custom timeline markers using the official samples. I discovered that when I use the TrackAsset.CreateMark method to create a custom marker, the MarkEditor.OnCreate method is not called. However, if I create a custom marker by right-clicking on a track and selecting “Add Annotation,” the OnCreate method is called as expected.

After reviewing part of the timeline code, I found that the OnCreate method is triggered by the following line: CustomTimelineEditorCache.GetMarkerEditor(newMarker).OnCreate(newMarker, null);. Unfortunately, since CustomTimelineEditorCache is an internal class, I cannot call it directly.

How can I trigger the OnCreate method after using a custom CreateMark function?

Part of code:


namespace Timeline.Samples {
    [MenuEntry("Create Annotation from clipboard contents")]
    public class CreateAnnotationAction : TimelineAction {
        // *** other methods *** //
        public override bool Execute(ActionContext context) {
            double time;
            if (context.invocationTime.HasValue) {
                time = context.invocationTime.Value;
            } else {
                time = TimelineEditor.inspectedDirector.time;
            }

            if (time < 0f) {
                return false;
            }

            string clipboardTextContent = EditorGUIUtility.systemCopyBuffer;

            IEnumerable<TrackAsset> selectedTracks = context.tracks;
            foreach (TrackAsset track in selectedTracks) {
                GroupTrack groupTrack = track as GroupTrack;
                if (!ReferenceEquals(groupTrack, null)) {
                    continue;
                }

                AnnotationMarker annotation = track.CreateMarker<AnnotationMarker>(time); // not call OnCreate
                annotation.description = clipboardTextContent;
                annotation.title = "Annotation from clipboard";
                annotation.name = "Annotation";
            }

            return true;
        }
    }
}

namespace Timeline.Samples {
    [CustomTimelineEditor(typeof(AnnotationMarker))]
    public class AnnotationMarkerMarkerEditor : MarkerEditor {
        private const float k_LineOverlayWidth = 3.0f;

        private const string k_OverlayPath = "timeline_annotation_overlay";
        private const string k_OverlaySelectedPath = "timeline_annotation_overlay_selected";
        private const string k_OverlayCollapsedPath = "timeline_annotation_overlay_collapsed";

        private static readonly Texture2D s_OverlayTexture;
        private static readonly Texture2D s_OverlaySelectedTexture;
        private static readonly Texture2D s_OverlayCollapsedTexture;

        private const string IconName = "AnnotationMarkerIcon";
        private static Texture2D s_Icon;

        [InitializeOnLoadMethod]
        private static void InitializeOnLoad() {
            s_Icon = Resources.Load<Texture2D>(IconName);
        }

        public override void OnCreate(IMarker marker, IMarker clonedFrom) {
            base.OnCreate(marker, clonedFrom);
            if (marker is not AnnotationMarker annotation) {
                return;
            }

            EditorGUIUtility.SetIconForObject(annotation, s_Icon);
        }
    }
}