创建自己的覆盖层

可以为场景视图窗口创建自定义面板覆盖层和工具栏覆盖层。

• 面板覆盖层
• 工具栏覆盖层

提示：有关创建 UIElement 的信息，请参阅 UI 元素开发者指南。

了解 EditorToolbarElement

工具栏元素可以包含文本、图标或两者的组合。

使用 EditorToolbarElement(Identifier, EditorWindowType) 注册工具栏元素以便在 ToolbarOverlay 实现中使用。

可以继承任何 VisualElement 类型并自行创建样式，但工具栏元素需要特定样式。最好继承自以下预定义 EditorToolbar 类型之一：

• EditorToolbarButton：基于 UnityEditor.UIElements.ToolbarButton
• EditorToolbarToggle：基于 UnityEditor.UIElements.ToolbarToggle
• EditorToolbarDropdown：基于 EditorToolbarButton
• EditorToolbarDropdownToggle：基于 UnityEngine.UIElements.BaseField

提示：如果工具栏水平或垂直停靠，则其文本可能不可见或被裁剪。可以为每个工具栏指定一个图标，避免文本裁剪。

创建面板覆盖层

所有覆盖层必须继承自 Overlay 基类并实现 CreatePanelContent 方法。这将创建一个基本面板，可以使用该面板并可向其添加工具栏元素。

要创建面板覆盖层，请执行以下操作：

1. 在 Editor 文件夹中创建一个新的 C# 脚本并为其命名。

2. 打开创建的脚本。

3. 从脚本中删除默认内容。

4. 从 UnityEditor.Overlays 命名空间实现 Overlay 类。

5. 覆盖 CreatePanelContent 函数，并将内容添加到视觉元素。

6. 将 OverlayAttribute 属性添加到类中。

7. 在 OverlayAttribute 中，指定希望此覆盖层位于哪种类型的窗口中：

   • 如果希望该覆盖层在所有编辑器窗口中可用，请将类型指定为 EditorWindow。
   • 如果希望该覆盖层仅在场景视图中可用，请将类型指定为 SceneView。

8. 在 OverlayAttribute 中，将名称、ID 和显示名称添加到该覆盖层。

9. 要添加在折叠覆盖层时显示的图标，请将 Icon 属性添加到 Overlay 类并指定一个图标。如果该覆盖层没有图标，则默认情况下，系统使用覆盖层名称的前两个字母或前两个单词的前两个首字母。

示例

using UnityEditor;
using UnityEditor.Overlays;
using UnityEngine.UIElements;
[Overlay(typeof(SceneView), "Panel Overlay Example", true)]
public class MyToolButtonOverlay : Overlay
{
    public override VisualElement CreatePanelContent()
    {
        var root = new VisualElement() { name = "My Toolbar Root" };
        root.Add(new Label() { text = "Hello" });
        return root;

    }
}

创建工具栏覆盖层

工具栏覆盖层是包含工具栏项的容器，由 EditorToolbarElement 的集合组成。

工具栏覆盖层具有内置的水平、垂直和面板布局。ToolbarOverlay 实现了一个传递 EditorToolbarElementAttribute ID 的无参数构造函数。与面板覆盖层不同，内容定义为独立部分，收集后形成元素条带。

创建工具栏覆盖层时，请执行以下操作：

• 使用 EditorToolbarElement(Identifier, EditorWindowType) 注册要在 ToolbarOverlay 实现中使用的工具栏元素。
• 使用 OverlayAttribute 标记所有覆盖层。
• 确保工具栏覆盖层继承 ToolbarOverlay 并实现无参数构造函数。
• 确保工具栏的内容填充了将传递给基构造函数的字符串 ID。
• 确保 ID 由 EditorToolbarElementAttribute 定义。
• 使用 Icon 属性可将图标添加到覆盖层。折叠覆盖层时，图标可见。如果覆盖层没有图标，则在折叠覆盖层时显示覆盖层名称的前两个字母（或前两个单词的前两个首字母）。

在覆盖层中实现特定于 ToolbarOverlay 的元素时：

• IAccessContainerWindow 界面仅适用于工具栏。元素不知道其上下文。在 DropdownToggleExample 中，如果切换元素，将不执行任何操作。
• 对视觉效果使用 UIElement 样式。工具栏元素在覆盖层中没有样式。

要创建工具栏覆盖层，请执行以下操作：

1. 在 Editor 文件夹中创建一个新的 C# 脚本并为其命名。
2. 打开创建的脚本。
3. 从脚本中删除默认内容。
4. 向脚本添加工具栏元素。
5. 将工具栏元素添加到覆盖层构造函数。
6. 添加面板覆盖层并实现工具栏元素。

示例

以下示例是名为 Element Toolbars Example 的覆盖层，演示了以下工具栏元素：

• EditorToolbarButton
• EditorToolbarToggle
• EditorToolbarDropdown
• EditorToolbarDropdownToggle

每个工具栏元素都创建为独立类，然后添加到覆盖层面板。

此覆盖层：

• 可以水平和垂直排列为面板。
• 具有包含文本和工具提示的按钮。
• 具有由 Icon 属性定义的工具栏图标。折叠覆盖层时显示此图标。

    using System.Collections;
    using System.Collections.Generic;
    using System.Text;
    using UnityEngine;
    using UnityEditor.EditorTools;
    using UnityEditor.Toolbars;
    using UnityEditor.Overlays;
    using UnityEngine.UIElements;
    using UnityEditor;

    // Use [EditorToolbarElement(Identifier, EditorWindowType)] to register toolbar elements for use in ToolbarOverlay implementation.

    [EditorToolbarElement(id, typeof(SceneView))]
    class DropdownExample : EditorToolbarDropdown
    {
        public const string id = "ExampleToolbar/Dropdown";

        static string dropChoice = null;

        public DropdownExample()
        {
            text = "Axis";
            clicked += ShowDropdown;
        }

        void ShowDropdown()
        {
            var menu = new GenericMenu();
            menu.AddItem(new GUIContent("X"), dropChoice == "X", () => { text = "X"; dropChoice = "X"; });
            menu.AddItem(new GUIContent("Y"), dropChoice == "Y", () => { text = "Y"; dropChoice = "Y"; });
            menu.AddItem(new GUIContent("Z"), dropChoice == "Z", () => { text = "Z"; dropChoice = "Z"; });
            menu.ShowAsContext();
        }
    }
    [EditorToolbarElement(id, typeof(SceneView))]
    class ToggleExample : EditorToolbarToggle
    {
        public const string id = "ExampleToolbar/Toggle";
        public ToggleExample()
        {
            text = "Toggle OFF";
            this.RegisterValueChangedCallback(Test);
        }

        void Test(ChangeEvent<bool> evt)
        {
            if (evt.newValue)
            {
                Debug.Log("ON");
                text = "Toggle ON";
            }
            else
            {
                Debug.Log("OFF");
                text = "Toggle OFF";
            }
        }
    }

    [EditorToolbarElement(id, typeof(SceneView))]
    class DropdownToggleExample : EditorToolbarDropdownToggle, IAccessContainerWindow
    {
        public const string id = "ExampleToolbar/DropdownToggle";

        // This property is specified by IAccessContainerWindow and is used to access the Overlay's EditorWindow.

        public EditorWindow containerWindow { get; set; }
        static int colorIndex = 0;
        static readonly Color[] colors = new Color[] { Color.red, Color.green, Color.cyan };
        public DropdownToggleExample()
        {
            text = "Color Bar";
            tooltip = "Display a color rectangle in the top left of the Scene view. Toggle on or off, and open the dropdown" +
                      "to change the color.";

        // When the dropdown is opened, ShowColorMenu is invoked and we can create a popup menu.

            dropdownClicked += ShowColorMenu;

        // Subscribe to the Scene view OnGUI callback so that we can draw our color swatch.

            SceneView.duringSceneGui += DrawColorSwatch;
        }

        void DrawColorSwatch(SceneView view)
        {

         // Test that this callback is for the Scene View that we're interested in, and also check if the toggle is on
        // or off (value).

            if (view != containerWindow || !value)
            {
                return;
            }

            Handles.BeginGUI();
            GUI.color = colors[colorIndex];
            GUI.DrawTexture(new Rect(8, 8, 120, 24), Texture2D.whiteTexture);
            GUI.color = Color.white;
            Handles.EndGUI();
        }

        // When the dropdown button is clicked, this method will create a popup menu at the mouse cursor position.

        void ShowColorMenu()
        {
            var menu = new GenericMenu();
            menu.AddItem(new GUIContent("Red"), colorIndex == 0, () => colorIndex = 0);
            menu.AddItem(new GUIContent("Green"), colorIndex == 1, () => colorIndex = 1);
            menu.AddItem(new GUIContent("Blue"), colorIndex == 2, () => colorIndex = 2);
            menu.ShowAsContext();
        }
    }

    [EditorToolbarElement(id, typeof(SceneView))]
    class CreateCube : EditorToolbarButton//, IAccessContainerWindow
    {
        // This ID is used to populate toolbar elements.

        public const string id = "ExampleToolbar/Button";

        // IAccessContainerWindow provides a way for toolbar elements to access the `EditorWindow` in which they exist.
        // Here we use `containerWindow` to focus the camera on our newly instantiated objects after creation.
        //public EditorWindow containerWindow { get; set; }

        // Because this is a VisualElement, it is appropriate to place initialization logic in the constructor.
        // In this method you can also register to any additional events as required. In this example there is a tooltip, an icon, and an action.

        public CreateCube()
        {

    // A toolbar element can be either text, icon, or a combination of the two. Keep in mind that if a toolbar is
        // docked horizontally the text will be clipped, so usually it's a good idea to specify an icon.

            text = "Create Cube";
            icon = AssetDatabase.LoadAssetAtPath<Texture2D>("Assets/CreateCubeIcon.png");
            tooltip = "Instantiate a cube in the scene.";
            clicked += OnClick;
        }

        // This method will be invoked when the `Create Cube` button is clicked.

        void OnClick()
        {
            var newObj = GameObject.CreatePrimitive(PrimitiveType.Cube).transform;

        // When writing editor tools don't forget to be a good citizen and implement Undo!

            Undo.RegisterCreatedObjectUndo(newObj.gameObject, "Create Cube");

        //if (containerWindow is SceneView view)
        //    view.FrameSelected();

        }

    }

    // All Overlays must be tagged with the OverlayAttribute

    [Overlay(typeof(SceneView), "ElementToolbars Example")]

        // IconAttribute provides a way to define an icon for when an Overlay is in collapsed form. If not provided, the name initials are used.

    [Icon("Assets/unity.png")]

    // Toolbar Overlays must inherit `ToolbarOverlay` and implement a parameter-less constructor. The contents of a toolbar are populated with string IDs, which are passed to the base constructor. IDs are defined by EditorToolbarElementAttribute.

    public class EditorToolbarExample : ToolbarOverlay
    {

     // ToolbarOverlay implements a parameterless constructor, passing the EditorToolbarElementAttribute ID.
    // This is the only code required to implement a toolbar Overlay. Unlike panel Overlays, the contents are defined
    // as standalone pieces that will be collected to form a strip of elements.

        EditorToolbarExample() : base(
            CreateCube.id,
            ToggleExample.id,
            DropdownExample.id,
            DropdownToggleExample.id
            )
        { }
    }

工具栏元素实现

工具栏元素的控件与 UIToolkit 中的控件相同，但它们继承了一些工具栏功能和特定样式。

本节包含以下工具栏元素的示例：

• EditorToolbarButton
• EditorToolbarToggle
• EditorToolbarDropdown
• EditorToolbarDropdownToggle

EditorToolbarButton

EditorToolbarButton 是一个包含元素逻辑的独立类。以下示例创建了一个按钮，在单击立方体时会生成一个立方体：

[EditorToolbarElement(id, typeof(SceneView))]
class CreateCube : EditorToolbarButton
{
// This ID is used to populate toolbar elements.

public const string id = "ExampleToolbar/Button";

// Because this is a VisualElement, it is appropriate to place initialization logic in the constructor.

// In this method you can also register to any additional events as required. In this example there is a tooltip, an icon, and an action.

    public CreateCube()
       {

// A toolbar element can be either text, icon, or a combination of the two. Keep in mind that if a toolbar is docked horizontally the text will be clipped, so it's a good idea to specify an icon.

            text = "Create Cube";
            icon = AssetDatabase.LoadAssetAtPath<Texture2D>("Assets/CreateCubeIcon.png");
            tooltip = "Instantiate a cube in the scene.";
            clicked += OnClick;
}

void OnClick()
{
    var newObj = GameObject.CreatePrimitive(PrimitiveType.Cube).transform;

    // When writing editor tools, don't forget to be a good citizen and implement Undo.

    Undo.RegisterCreatedObjectUndo(newObj.gameObject, "Create Cube");

// Note: Using ObjectFactory class instead of GameObject(like in this example) will register the undo entry automatically removing the need to register manually.

}
}

将元素的 ID 添加到 Overlay 构造函数：

[Overlay(typeof(SceneView), "ElementToolbar Example")]
[Icon("Assets/unity.png")]
public class EditorToolbarExample : ToolbarOverlay
{
    EditorToolbarExample() : base(CreateCube.id) { }

}

EditorToolbarToggle

创建一个包含元素所有逻辑的独立类。以下示例创建了一个开关，用于在控制台中打印其状态并在元素中更新其文本：

[EditorToolbarElement(id, typeof(SceneView))]
class ToggleExample : EditorToolbarToggle
{
    public const string id = "ExampleToolbar/Toggle";
    public ToggleExample()
    {
        text = "Toggle OFF";

    // Register the class to a callback for when the toggle’s state changes

        this.RegisterValueChangedCallback(OnStateChange);
    }

    void OnStateChange(ChangeEvent<bool> evt)
    {
        if (evt.newValue)
        {

    // Put logic for when the state is ON here

                Debug.Log("Toggle State -> ON");
        text = "Toggle ON";
        }
        else
        {

    // Put logic for when the state is OFF here

                Debug.Log("Toggle State -> OFF");
        text = "Toggle OFF";
        }
    }
}

将元素的 ID 添加到 Overlay 构造函数：

[Overlay(typeof(SceneView), "ElementToolbar Example")]
[Icon("Assets/unity.png")]
public class EditorToolbarExample : ToolbarOverlay
{
    EditorToolbarExample() : base(
ToggleExample.id
) { }

}

EditorToolbarDropdown

创建一个包含元素所有逻辑的独立类。下面是一个使用下拉选单调整其文本的简单下拉选单示例。

[EditorToolbarElement(id, typeof(SceneView))]
class DropdownExample : EditorToolbarDropdown
{
    public const string id = "ExampleToolbar/Dropdown";

    static string dropChoice = null;

    public DropdownExample()
    {
        text = "Axis";
        clicked += ShowDropdown;
    }

    void ShowDropdown()
    {

// A simple GenericMenu to populate the dropdown content

        var menu = new GenericMenu();
        menu.AddItem(new GUIContent("X"), dropChoice == "X", () => { text = "X"; dropChoice = "X"; });
        menu.AddItem(new GUIContent("Y"), dropChoice == "Y", () => { text = "Y"; dropChoice = "Y"; });
        menu.AddItem(new GUIContent("Z"), dropChoice == "Z", () => { text = "Z"; dropChoice = "Z"; });
        menu.ShowAsContext();
    }
}

将元素的 ID 添加到 Overlay 构造函数：

[Overlay(typeof(SceneView), "ElementToolbar Example")]
[Icon("Assets/unity.png")]
public class EditorToolbarExample : ToolbarOverlay
{
    EditorToolbarExample() : base(
DropdownExample.id
) { }

}

EditorToolbarDropdownToggle

创建一个包含元素所有逻辑的独立类。下拉选单切换是指可以像场景视图中的辅助图标菜单一样切换的下拉选单。此示例在场景视图的一角创建了一个矩形，可从覆盖层的下拉选单中选择其颜色。

[EditorToolbarElement(id, typeof(SceneView))]
class DropdownToggleExample : EditorToolbarDropdownToggle, IAccessContainerWindow
{
    public const string id = "ExampleToolbar/DropdownToggle";


    // This property is specified by IAccessContainerWindow and is used to access the Overlay's EditorWindow.

    public EditorWindow containerWindow { get; set; }
    static int colorIndex = 0;
    static readonly Color[] colors = new Color[] { Color.red, Color.green, Color.cyan };
    public DropdownToggleExample()
    {
        text = "Color Bar";
        tooltip = "Display a color rectangle in the top left of the Scene view. Toggle on or off, and open the dropdown" +
                "to change the color.";


   // When the dropdown is opened, ShowColorMenu is invoked and you can create a pop-up menu.

        dropdownClicked += ShowColorMenu;


    // Subscribe to the Scene view OnGUI callback to draw a color swatch.

        SceneView.duringSceneGui += DrawColorSwatch;
    }


    void DrawColorSwatch(SceneView view)
    {

        // Test that this callback is for the correct Scene view, and check if the toggle is on
     // or off (value).

        if (view != containerWindow || !value)
        {
            return;
        }


        Handles.BeginGUI();
            GUI.color = colors[colorIndex];
        GUI.DrawTexture(new Rect(8, 8, 120, 24), Texture2D.whiteTexture);
        GUI.color = Color.white;
        Handles.EndGUI();
    }


    // When the drop-down button is clicked, this method creates a pop-up menu at the mouse cursor position.

    void ShowColorMenu()
    {
        var menu = new GenericMenu();
        menu.AddItem(new GUIContent("Red"), colorIndex == 0, () => colorIndex = 0);
        menu.AddItem(new GUIContent("Green"), colorIndex == 1, () => colorIndex = 1);
        menu.AddItem(new GUIContent("Blue"), colorIndex == 2, () => colorIndex = 2);
        menu.ShowAsContext();
    }
}

将元素的 ID 添加到 Overlay 构造函数：

[Overlay(typeof(SceneView), "ElementToolbar Example")]
[Icon("Assets/unity.png")]
public class EditorToolbarExample : ToolbarOverlay
{
    EditorToolbarExample() : base(
DropdownToggleExample.id
) { }


}