OverlayCanvas.Add(Overlay,bool)

参数

描述

将一个 Overlay 添加到此画布。添加的 Overlay 将在关联的 EditorWindow 中显示，直到它们被移除。

在大多数情况下，Overlay 使用 OverlayAttribute 自动实例化。但是，也可以直接从 OverlayCanvas 添加和移除 Overlay。这对于需要某些上下文的短暂 Overlay 很有用。例如，作为编辑器的扩展。

使用此方法添加的 Overlay 必须实现 ITransientOverlay。一个 Overlay 只能属于一个 OverlayCanvas。要在多个窗口中显示一个 Overlay，您必须为每个窗口实例化一个 Overlay。

using UnityEditor;
using UnityEngine;
using UnityEditor.Overlays;
using UnityEngine.UIElements;

// Attach this MonoBehaviour to a GameObject to view the example Overlay in the last active Scene View
class OverlayCanvasExample : MonoBehaviour {}

// An Editor for our OverlayCanvasExample MonoBehaviour. This will show and hide the example Overlay when a GameObject
// with the OverlayCanvasExample component is selected and deselected.
[CustomEditor(typeof(OverlayCanvasExample))]
class OverlayCanvasExampleEditor : UnityEditor.Editor
{
    ExampleEditorOverlay m_Overlay;

    void OnEnable()
    {
        // Create a new Overlay with a label indicating the selected GameObject name.
        m_Overlay = new ExampleEditorOverlay(name);
        SceneView.lastActiveSceneView.overlayCanvas.Add(m_Overlay);
    }

    void OnDisable()
    {
        // If the Overlay has not already been closed, close it when this editor is disabled. Added Overlays will
        // persist until they are closed.
        m_Overlay?.Close();
    }
}

class ExampleEditorOverlay : Overlay, ITransientOverlay
{
    // Overlays added directly to the canvas must implement ITransientOverlay, meaning they control their own lifecycle.
    public bool visible => true;

    string m_Message;

    public ExampleEditorOverlay(string message)
    {
        m_Message = message;
    }

    public override VisualElement CreatePanelContent()
    {
        var root = new VisualElement();
        root.Add(new Label(m_Message));
        root.Add(new Button(Close) { text = "Close" });
        return root;
    }
}