ngui的版本为3.6.8，在其中添加代码：

1. [csharp] 
2. /// <summary>
3. /// Renderer's sorting order, to be used with Unity's 2D system.
4. /// </summary>
5. public int sortingOrder
6. {
7. get { return (mRenderer != null) ? mRenderer.sortingOrder : 0; }
8. set { if (mRenderer != null && mRenderer.sortingOrder != value) mRenderer.sortingOrder = value; }
9. }
10. // added by Clark
11. public string sortingLayerName
12. {
13. get { return (mRenderer != null) ? mRenderer.sortingLayerName : "default"; }
14. set
15. {
16. if(mRenderer != null && mRenderer.sortingLayerName != value)
17. {
18. mRenderer.sortingLayerName = value;
19. if UNITY_EDITOR
20. UnityEditor.EditorUtility.SetDirty(gameObject);
21. endif
22. }
23. }
24. }
25. // added end by Clark

1. [csharp] 
2. /// <summary>
3. /// Create a new draw call, reusing an old one if possible.
4. /// </summary>
5. static UIDrawCall Create (string name, UIPanel pan, Material mat, Texture tex, Shader shader)
6. {
7. UIDrawCall dc = Create(name);
8. dc.gameObject.layer = pan.cachedGameObject.layer;
9. dc.baseMaterial = mat;
10. dc.mainTexture = tex;
11. dc.shader = shader;
12. dc.renderQueue = pan.startingRenderQueue;
13. dc.sortingOrder = pan.sortingOrder;
14. // added by Clark
15. dc.sortingLayerName = pan.sortingLayerName;
16. // added end by Clark
17. dc.manager = pan;
18. return dc;
19. }

1. [csharp]
2. // Clipping rectangle
3. [HideInInspector][SerializeField] UIDrawCall.Clipping mClipping = UIDrawCall.Clipping.None;
4. [HideInInspector][SerializeField] Vector4 mClipRange = new Vector4(0f, 0f, 300f, 200f);
5. [HideInInspector][SerializeField] Vector2 mClipSoftness = new Vector2(4f, 4f);
6. [HideInInspector][SerializeField] int mDepth = 0;
7. [HideInInspector][SerializeField] int mSortingOrder = 0;
8. // added by Clark
9. [HideInInspector][SerializeField] string mSortingLayerName;
10. // added end by Clark

1. [csharp] 
2. public int sortingOrder
3. {
4. get
5. {
6. return mSortingOrder;
7. }
8. set
9. {
10. if (mSortingOrder != value)
11. {
12. mSortingOrder = value;
13. if UNITY_EDITOR
14. NGUITools.SetDirty(this);
15. endif
16. UpdateDrawCalls();
17. }
18. }
19. }
20. // added by Clark
21. public string sortingLayerName
22. {
23. get { return mSortingLayerName; }
24. set
25. {
26. if(mSortingLayerName != value)
27. {
28. mSortingLayerName = value;
29. if UNITY_EDITOR
30. NGUITools.SetDirty(this);
31. endif
32. UpdateDrawCalls();
33. }
34. }
35. }
36. // added end by Clark

1. [csharp]
2. for (int i = 0; i < drawCalls.Count; ++i)
3. {
4. UIDrawCall dc = drawCalls[i];
5. Transform t = dc.cachedTransform;
6. t.position = pos;
7. t.rotation = rot;
8. t.localScale = scale;
9. dc.renderQueue = (renderQueue == RenderQueue.Explicit) ? startingRenderQueue : startingRenderQueue + i;
10. dc.alwaysOnScreen = alwaysOnScreen &&
11. (mClipping == UIDrawCall.Clipping.None || mClipping == UIDrawCall.Clipping.ConstrainButDontClip);
12. dc.sortingOrder = mSortingOrder;
13. // added by Clark
14. dc.sortingLayerName = mSortingLayerName;
15. // added end by Clark
16. }

1. [csharp] 
2. using UnityEngine;
3. using UnityEditor;
4. using System.Collections.Generic;
5. // added by Clark
6. using System;
7. using System.Reflection;
8. using UnityEditorInternal;
9. // added end by Clark

1. [csharp]
2. UIWidget.Pivot mDragPivot = UIWidget.Pivot.Center;
3. GUIStyle mStyle0 = null;
4. GUIStyle mStyle1 = null;
5. // added by Clark
6. string[] sortingLayerNames;
7. // added end by Clark

1. [csharp] 
2. protected override void OnEnable ()
3. {
4. base.OnEnable();
5. mPanel = target as UIPanel;
6. // added by Clark
7. sortingLayerNames = GetSortingLayerNames();
8. // added end by Clark
9. }

1. [csharp]
2. GUI.changed = false;
3. int so = EditorGUILayout.IntField("Sort Order", mPanel.sortingOrder, GUILayout.Width(120f));
4. if (GUI.changed) mPanel.sortingOrder = so;
5. // added by Clark
6. int sortingLayerIndex = GetSortingLayerIndex(mPanel.sortingLayerName);
7. int newSortingLayerIndex = EditorGUILayout.Popup("Sorting Layer", sortingLayerIndex, sortingLayerNames);
8. if(sortingLayerIndex != newSortingLayerIndex)
9. {
10. mPanel.sortingLayerName = sortingLayerNames[newSortingLayerIndex];
11. }
12. // added end by Clark

1. [csharp] 
2. // added by Clark
3. string[] GetSortingLayerNames()
4. {
5. Type t = typeof(InternalEditorUtility);
6. PropertyInfo prop = t.GetProperty("sortingLayerNames", BindingFlags.Static | BindingFlags.NonPublic);
7. return (string[])prop.GetValue(null, null);
8. }
9. int GetSortingLayerIndex(string layerName)
10. {
11. for(int i = 0; i < sortingLayerNames.Length; i++)
12. {
13. if(sortingLayerNames[i] == layerName)
14. {
15. return i;
16. }
17. }
18. return 0;
19. }
20. // added end by Clark