在Scene窗口编辑UI界面时，当重叠的UI元素较多时，很难点选想要选中的元素，UI Selector工具做了如下功能：右键时弹出一个列表，列举所有包含鼠标当前位置的RectTransform物体，在列表中选择即可选中该UI元素。
实现该功能需要使用Scene View类，本人用的Unity版本是2020.3.16，该版本里显示onSceneGUIDelegate是弃用状态，使用duringSceneGui代替：
using UnityEngine;
using UnityEditor;
namespace SK.Framework
{
[InitializeOnLoad]
public static class UISelector
{
static UISelector()
{
SceneView.duringSceneGui = OnSceneGUI;
}
private static void OnSceneGUI(SceneView sceneView)
{
}
}
}注意使用InitializeOnLoad属性，该属性应用的对象是静态构造函数，它可以保证在编辑器启动的时候调用该构造函数，因此我们在构造函数中使用SceneView类中的duringSceneGui来实现Scene窗口的自定义功能。
首先我们想要在鼠标右键点击时弹出列表，在编辑器环境中的输入使用Event类，下面的代码表示鼠标右键抬起：
代码语言：javascript复制var ec = Event.current;
if (ec != null && ec.button == 1 && ec.type == EventType.MouseUp)
{
}列表中列举所有包含当前鼠标位置的Rect Transform，所以要先获取当前加载的场景中的所有Rect Transform组件：
代码语言：javascript复制private static void OnSceneGUI(SceneView sceneView)
{
var ec = Event.current;
if (ec != null && ec.button == 1 && ec.type == EventType.MouseUp)
{
ec.Use();
var scenes = GetAllScenes();
var groups = scenes
.Where(m => m.isLoaded)
.SelectMany(m => m.GetRootGameObjects())
.Where(m => m.activeInHierarchy)
.SelectMany(m => m.GetComponentsInChildren<RectTransform>())
.GroupBy(m => m.gameObject.scene.name)
.ToArray();
}
}
private static IEnumerable<Scene> GetAllScenes()
{
for (int i = 0; i < SceneManager.sceneCount; i )
{
yield return SceneManager.GetSceneAt(i);
}
}获取到所有的RectTransform组件后，判断哪些包含当前鼠标位置，通过Event.current中的mousePosition可以获得当前鼠标位置，但是需要注意，该坐标系中的原点为左上角：
而UGUI中Canvas的坐标系以左下角为原点，因此需要先进行坐标转换，然后再通过Rect Transform Utility类中的RectangleContainsScreenPoint函数可以判断RectTransform是否包含指定位置：
代码语言：javascript复制using UnityEngine;
using UnityEditor;
using System.Linq;
using System.Collections.Generic;
using UnityEngine.SceneManagement;
namespace SK.Framework
{
[InitializeOnLoad]
public static class UISelector
{
static UISelector()
{
SceneView.duringSceneGui = OnSceneGUI;
}
private static void OnSceneGUI(SceneView sceneView)
{
var ec = Event.current;
if (ec != null && ec.button == 1 && ec.type == EventType.MouseUp)
{
ec.Use();
// 当前屏幕坐标，左上角是（0，0）右下角（camera.pixelWidth，camera.pixelHeight）
Vector2 mousePosition = Event.current.mousePosition;
// Retina 屏幕需要拉伸值
float mult = EditorGUIUtility.pixelsPerPoint;
// 转换成摄像机可接受的屏幕坐标，左下角是（0，0，0）右上角是（camera.pixelWidth，camera.pixelHeight，0）
mousePosition.y = sceneView.camera.pixelHeight - mousePosition.y * mult;
mousePosition.x *= mult;
var scenes = GetAllScenes();
var groups = scenes
.Where(m => m.isLoaded)
.SelectMany(m => m.GetRootGameObjects())
.Where(m => m.activeInHierarchy)
.SelectMany(m => m.GetComponentsInChildren<RectTransform>())
.Where(m => RectTransformUtility.RectangleContainsScreenPoint(m, mousePosition, sceneView.camera))
.GroupBy(m => m.gameObject.scene.name)
.ToArray();
}
}
private static IEnumerable<Scene> GetAllScenes()
{
for (int i = 0; i < SceneManager.sceneCount; i )
{
yield return SceneManager.GetSceneAt(i);
}
}
}
}同时还要处理同名UI元素问题，以及当前加载的场景可能不止一个的情况，如下：
最终通过GenericMenu类实现右键菜单，通过Selection类中activeTransform和EditorGUI Utility类中PingObject实现选中，完整代码：
代码语言：javascript复制using UnityEngine;
using UnityEditor;
using System.Linq;
using System.Collections.Generic;
using UnityEngine.SceneManagement;
namespace SK.Framework
{
[InitializeOnLoad]
public static class UISelector
{
static UISelector()
{
SceneView.duringSceneGui = OnSceneGUI;
}
private static void OnSceneGUI(SceneView sceneView)
{
var ec = Event.current;
if (ec != null && ec.button == 1 && ec.type == EventType.MouseUp)
{
ec.Use();
// 当前屏幕坐标，左上角是（0，0）右下角（camera.pixelWidth，camera.pixelHeight）
Vector2 mousePosition = Event.current.mousePosition;
// Retina 屏幕需要拉伸值
float mult = EditorGUIUtility.pixelsPerPoint;
// 转换成摄像机可接受的屏幕坐标，左下角是（0，0，0）右上角是（camera.pixelWidth，camera.pixelHeight，0）
mousePosition.y = sceneView.camera.pixelHeight - mousePosition.y * mult;
mousePosition.x *= mult;
var scenes = GetAllScenes();
var groups = scenes
.Where(m => m.isLoaded)
.SelectMany(m => m.GetRootGameObjects())
.Where(m => m.activeInHierarchy)
.SelectMany(m => m.GetComponentsInChildren<RectTransform>())
.Where(m => RectTransformUtility.RectangleContainsScreenPoint(m, mousePosition, sceneView.camera))
.GroupBy(m => m.gameObject.scene.name)
.ToArray();
var sceneCount = scenes.Count(m => m.isLoaded);
var gc = new GenericMenu();
var dic = new Dictionary<string, int>();
foreach (var group in groups)
{
foreach (var rt in group)
{
var name = rt.name;
var sceneName = rt.gameObject.scene.name;
var nameWithSceneName = sceneName "/" name;
var isContains = dic.ContainsKey(nameWithSceneName);
var text = sceneCount <= 1 ? name : nameWithSceneName;
if (isContains)
{
var count = dic[nameWithSceneName] ;
text = " [" count.ToString() "]";
}
var content = new GUIContent(text);
gc.AddItem(content, false, () =>
{
Selection.activeTransform = rt;
EditorGUIUtility.PingObject(rt.gameObject);
});
if (!isContains)
{
dic.Add(nameWithSceneName, 1);
}
}
}
gc.ShowAsContext();
}
}
private static IEnumerable<Scene> GetAllScenes()
{
for (int i = 0; i < SceneManager.sceneCount; i )
{
yield return SceneManager.GetSceneAt(i);
}
}
}
}
