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Unity Engine


OverlayIcon

Gets the VisualElement that represents an icon that overlays over the icon of the item. This element is hidden by default.
Read time 3 minutesLast updated 10 days ago

Definition

  • Type: Property
  • Namespace: Unity.Hierarchy
  • Assembly: UnityEngine.HierarchyModule
public VisualElement OverlayIcon { get; }

Remarks

Typically used to add an icon that indicates the state of the item. For example, you can use this to display an icon over a GameObject's icon that indicates a prefab has a broken reference.
The following example adds a custom tooltip that displays in the Hierarchy window when you hover over any GameObject that has a custom component named
Notes
attached to it. It uses
OverlayIcon
to add the custom overlay indicator to the icon of the GameObject.
The example requires a USS file called
CustomTooltip.uss
and a custom MonoBehaviour script called
Notes.cs
.
To use this example:
  1. Save the script in a folder called
    Assets/Editor/CustomTooltip
    . Scripts in an
    Editor
    folder can use the Hierarchy module API without additional setup. If you save the script outside of an
    Editor
    folder, you must enable the Hierarchy built-in module in the Package Manager window, which also adds the module to your Player builds.
  2. Copy the styles from the USS example on this page. Save them in a USS file called
    CustomTooltip.uss
    in the same
    Assets/Editor/CustomTooltip
    folder.
  3. Save the
    Notes.cs
    script outside of an
    Editor
    folder, because MonoBehaviour scripts in an
    Editor
    folder can't be attached to GameObjects.
  4. Add the
    Notes
    component to a GameObject.
  5. In the Inspector window, enter text in the Note field of the
    Notes
    component.
  6. In the Hierarchy window, hover over the name of the GameObject to display the text as a tooltip. A small overlay indicator also displays in the corner of the icon of any GameObject that has a note.
using System.Text; using Unity.Hierarchy; using Unity.Hierarchy.Editor; using UnityEditor; using UnityEngine; using UnityEngine.UIElements; namespace Unity.HierarchySamples.Editor { class CustomTooltip { const string k_NotesOverlayUssClassName = "hierarchy-item__notes-overlay"; [InitializeOnLoadMethod] static void Initialize() { HierarchyWindow.BindView += OnBindView; HierarchyWindow.BindViewItem += OnBindViewItem; HierarchyWindow.GetTooltip += OnGetTooltip; } static void OnBindView(HierarchyWindow window, HierarchyView view) => view.styleSheets.Add(AssetDatabase.LoadAssetAtPath<StyleSheet>("Assets/Editor/CustomTooltip/CustomTooltip.uss")); static void OnBindViewItem(HierarchyWindow window, HierarchyView view, HierarchyViewItem item) { if (item.Handler is not HierarchyGameObjectHandler handler) return; GameObject gameObject = handler.GetGameObject(item.Node); bool hasNotes = gameObject.TryGetComponent<Notes>(out Notes notes) && !string.IsNullOrWhiteSpace(notes.note); VisualElement notesOverlay = item.OverlayIcon.Q(className: k_NotesOverlayUssClassName); if (hasNotes) { if (notesOverlay == null) { notesOverlay = new VisualElement(); notesOverlay.AddToClassList(k_NotesOverlayUssClassName); item.OverlayIcon.Add(notesOverlay); } } else if (notesOverlay != null) { notesOverlay.RemoveFromHierarchy(); } } static void OnGetTooltip(HierarchyWindow window, HierarchyView view, HierarchyViewItem item, StringBuilder tooltip, bool filtering) { if (item.Handler is not HierarchyGameObjectHandler handler) return; GameObject gameObject = handler.GetGameObject(item.Node); if (!gameObject.TryGetComponent<Notes>(out Notes notes) || string.IsNullOrWhiteSpace(notes.note)) return; if (filtering) { // When filtering, append the note to the existing tooltip. tooltip.Append("\nNote: "); tooltip.Append(notes.note); } else { // When not filtering, fully override the tooltip. tooltip.Clear(); tooltip.Append("Note: "); tooltip.Append(notes.note); } } } }
The following example shows how to style
CustomTooltip.uss
.
.hierarchy-item__notes-overlay { position: absolute; width: 100%; height: 100%; background-size: 8px 8px; background-position: top left; background-repeat: no-repeat; background-image: var(--unity-icons-console_entry_info_small); }
The following example shows the
Notes
component that the CustomTooltip example uses.
using UnityEngine; namespace Unity.HierarchySamples { // Simple component that allows attaching notes to GameObjects for display in custom tooltips. public class Notes : MonoBehaviour { [TextArea(3, 10)] public string note; } }