需求

想拓展一下UGUI的Button,找了几个帖子，只是能实现功能，但是用起来总有些不尽人意的地方，想办法处理一下

实现

1.创建继承自Button的类

using UnityEngine;
using UnityEngine.UI;

public class CustomButton : Button
{
    [SerializeField] public int audioKey = -1;
    
    protected override void Start()
    {
        base.Start();
        onClick.AddListener(PlaySound);
    }
    
    private void PlaySound()
    {
        if (audioKey != -1)
        {
            // AudioManager.Instance.PlaySound(audioKey);
        }
    }
}

这里只临时做一丢丢功能示例，我们预期的是上面代码中的属性在Inspector中显示出来，然而并没有

2.处理Inspector 显示问题

using UnityEditor;
[CustomEditor(typeof(CustomButton))]
public class CustomButtonEditor : UnityEditor.UI.ButtonEditor
{
    public override void OnInspectorGUI()
    {
        var btn = (CustomButton)target;
        btn.audioKey = EditorGUILayout.IntField("Audio Key", btn.audioKey);
        base.OnInspectorGUI();
    }
}

如图，属性已经能正确显示

目前只能通过AddComponent的方式创建，我们预期的是和unity 自带的Button一样的创建方式
注意：editor脚本继承自对应组件的Editor,如上面Button的，继承自 UnityEditor.UI.ButtonEditor，否则Inspector显示可能出现问题

3.处理在prafab中和hierarchy中创建按钮

• 整理一下Button的使用体验
• 1. 右键创建
• 2. 自动挂载Image,用于接收raycast
• 3. 自动挂载text显示文案
• 4. 创建节点时，需要区分是否是编辑prefab模式，是否有选中的父节点,确定生成节点的位置
• 5. 创建节点时，需要区分是否在canvas下等情况，是否需要生成canvas

using System.Collections;
using System.Collections.Generic;
using TMPro;
using UnityEditor;
using UnityEngine;
using UnityEngine.UI;

public class CustomUI : Editor
{
    [MenuItem("GameObject/UI/CustomButton")]
    public static void CreateCustomButton()
    {
        //创建按钮
        var btn = ObjectFactory.CreateGameObject("CustomButton");
        ObjectFactory.AddComponent<RectTransform>(btn);
        var img = ObjectFactory.AddComponent<Image>(btn);
        img.raycastTarget = true;
        img.type = Image.Type.Sliced;
        img.sprite = AssetDatabase.GetBuiltinExtraResource<Sprite>("UI/Skin/UISprite.psd");
        ObjectFactory.AddComponent<CustomButton>(btn);
        if (!UnityEditor.SceneManagement.EditorSceneManager.IsPreviewSceneObject(btn))
        {
            //非prefab编辑模式下，需要找父节点canvas
            if (Selection.activeObject != null && Selection.activeObject is GameObject)
            {
                var go = (GameObject)Selection.activeObject;
                if (go.GetComponentInParent<Canvas>(true))
                {
                    btn.transform.SetParent(go.transform);
                }
                else
                {
                    var canvas = CreateCanvas();
                    canvas.transform.SetParent(go.transform);
                    btn.transform.SetParent(canvas.transform);
                }
            }
            else
            {
                var canvas = FindFirstObjectByType<Canvas>();
                if(canvas == null)
                {
                    canvas = CreateCanvas();
                }
                btn.transform.SetParent(canvas.transform);
            }
            
        }
        else
        {
            //prefab编辑模式下，直接添加到选中的物体下
            if (Selection.activeObject != null && Selection.activeObject is GameObject)
            {
                var go = (GameObject)Selection.activeObject;
                btn.transform.SetParent(go.transform);
            }
        }
        btn.GetComponent<RectTransform>().sizeDelta = new Vector2(160, 50);
        btn.transform.localPosition = Vector3.zero;
        //选中按钮节点
        Selection.activeObject = btn;
        //展开到当前节点
        Expend(btn.transform.parent,true);
        //文本
        var txt = ObjectFactory.CreateGameObject("Text");
        ObjectFactory.AddComponent<RectTransform>(txt);
        ObjectFactory.AddComponent<TextMeshProUGUI>(txt);
        txt.transform.SetParent(btn.transform);
        txt.transform.localPosition = Vector3.zero;
        txt.GetComponent<RectTransform>().sizeDelta = new Vector2(160, 50);
        
        //tmp
        var tmp = txt.GetComponent<TextMeshProUGUI>();
        tmp.alignment = TextAlignmentOptions.Center;
        tmp.raycastTarget = false;
        tmp.text = "button";
    }
    /// <summary>
    /// 创建Canvas
    /// </summary>
    /// <returns>canvas</returns>
    private static Canvas CreateCanvas()
    {
        var canvas = ObjectFactory.CreateGameObject("Canvas");
        var c = ObjectFactory.AddComponent<Canvas>(canvas);
        c.renderMode = RenderMode.ScreenSpaceOverlay;
        ObjectFactory.AddComponent<CanvasScaler>(canvas);
        ObjectFactory.AddComponent<GraphicRaycaster>(canvas);
        canvas.layer = LayerMask.NameToLayer("UI");
        return c;
    }
    private static void Expend(Transform transform,bool expand)
    {
        SceneHierarchyUtility.SetExpanded(transform.gameObject,expand);
        if(transform.parent != null)
        {
            Expend(transform.parent,expand);
        }
    }
   
    
}

添加按钮菜单如图所示

4.处理一些细节

创建后如图所示，节点正确创建了，但我们的预期是下面这样，自动选中+展开

自动选中比较简单

	Selection.activeObject = btn;

展开找了 网友的方法,很好用

using System.Collections.Generic;
using System.Reflection;
using UnityEditor;
using UnityEngine;


/// <summary>
/// Editor functionalities from internal SceneHierarchyWindow and SceneHierarchy classes. 
/// For that we are using reflection.
/// </summary>
public static class SceneHierarchyUtility
{
    /// <summary>
    /// Check if the target GameObject is expanded (aka unfolded) in the Hierarchy view.
    /// </summary>
    public static bool IsExpanded(GameObject go)
    {
        return GetExpandedGameObjects().Contains(go);
    }

    /// <summary>
    /// Get a list of all GameObjects which are expanded (aka unfolded) in the Hierarchy view.
    /// </summary>
    public static List<GameObject> GetExpandedGameObjects()
    {
        object sceneHierarchy = GetSceneHierarchy();

        MethodInfo methodInfo = sceneHierarchy
            .GetType()
            .GetMethod("GetExpandedGameObjects");

        object result = methodInfo.Invoke(sceneHierarchy, new object[0]);

        return (List<GameObject>)result;
    }

    /// <summary>
    /// Set the target GameObject as expanded (aka unfolded) in the Hierarchy view.
    /// </summary>
    public static void SetExpanded(GameObject go, bool expand)
    {
        object sceneHierarchy = GetSceneHierarchy();

        MethodInfo methodInfo = sceneHierarchy
            .GetType()
            .GetMethod("ExpandTreeViewItem", BindingFlags.NonPublic | BindingFlags.Instance);

        methodInfo.Invoke(sceneHierarchy, new object[] { go.GetInstanceID(), expand });
    }

    /// <summary>
    /// Set the target GameObject and all children as expanded (aka unfolded) in the Hierarchy view.
    /// </summary>
    public static void SetExpandedRecursive(GameObject go, bool expand)
    {
        object sceneHierarchy = GetSceneHierarchy();

        MethodInfo methodInfo = sceneHierarchy
            .GetType()
            .GetMethod("SetExpandedRecursive", BindingFlags.Public | BindingFlags.Instance);

        methodInfo.Invoke(sceneHierarchy, new object[] { go.GetInstanceID(), expand });
    }

    private static object GetSceneHierarchy()
    {
        EditorWindow window = GetHierarchyWindow();

        object sceneHierarchy = typeof(EditorWindow).Assembly
            .GetType("UnityEditor.SceneHierarchyWindow")
            .GetProperty("sceneHierarchy")
            .GetValue(window);

        return sceneHierarchy;
    }

    private static EditorWindow GetHierarchyWindow()
    {
        // For it to open, so that it the current focused window.
        EditorApplication.ExecuteMenuItem("Window/General/Hierarchy");
        return EditorWindow.focusedWindow;
    }
}

完成