接着上一篇文章的问题，看到了老外做的一个补丁，为ngui panel添加sorting layer，我也照着做了一个，这样ngui和unity2d就可以完全融合在一起了，层次关系可以任意设置。

ngui的版本为3.6.8，在其中添加代码：

文件：UIDrawCall.cs  109行左右

/// 
	/// Renderer's sorting order, to be used with Unity's 2D system.	/// 
	public int sortingOrder	{		get { return (mRenderer != null) ? mRenderer.sortingOrder : 0; }		set { if (mRenderer != null && mRenderer.sortingOrder != value) mRenderer.sortingOrder = value; }	}	// added by Clark	public string sortingLayerName	{		get { return (mRenderer != null) ? mRenderer.sortingLayerName : "default"; }		set		{			if(mRenderer != null && mRenderer.sortingLayerName != value)			{				mRenderer.sortingLayerName = value;#if UNITY_EDITOR				UnityEditor.EditorUtility.SetDirty(gameObject);#endif			}		}	}	// added end by Clark

/// 
	/// Create a new draw call, reusing an old one if possible.	/// 
	static UIDrawCall Create (string name, UIPanel pan, Material mat, Texture tex, Shader shader)	{		UIDrawCall dc = Create(name);		dc.gameObject.layer = pan.cachedGameObject.layer;		dc.baseMaterial = mat;		dc.mainTexture = tex;		dc.shader = shader;		dc.renderQueue = pan.startingRenderQueue;		dc.sortingOrder = pan.sortingOrder;		// added by Clark		dc.sortingLayerName = pan.sortingLayerName;		// added end by Clark		dc.manager = pan;		return dc;	}

// Clipping rectangle	[HideInInspector][SerializeField] UIDrawCall.Clipping mClipping = UIDrawCall.Clipping.None;	[HideInInspector][SerializeField] Vector4 mClipRange = new Vector4(0f, 0f, 300f, 200f);	[HideInInspector][SerializeField] Vector2 mClipSoftness = new Vector2(4f, 4f);	[HideInInspector][SerializeField] int mDepth = 0;	[HideInInspector][SerializeField] int mSortingOrder = 0;	// added by Clark	[HideInInspector][SerializeField] string mSortingLayerName;	// added end by Clark

252行左右

public int sortingOrder	{		get		{			return mSortingOrder;		}		set		{			if (mSortingOrder != value)			{				mSortingOrder = value;#if UNITY_EDITOR				NGUITools.SetDirty(this);#endif				UpdateDrawCalls();			}		}	}	// added by Clark	public string sortingLayerName	{		get { return mSortingLayerName; }		set		{			if(mSortingLayerName != value)			{				mSortingLayerName = value;#if UNITY_EDITOR				NGUITools.SetDirty(this);#endif				UpdateDrawCalls();			}		}	}	// added end by Clark

for (int i = 0; i < drawCalls.Count; ++i)		{			UIDrawCall dc = drawCalls[i];			Transform t = dc.cachedTransform;			t.position = pos;			t.rotation = rot;			t.localScale = scale;			dc.renderQueue = (renderQueue == RenderQueue.Explicit) ? startingRenderQueue : startingRenderQueue + i;			dc.alwaysOnScreen = alwaysOnScreen &&				(mClipping == UIDrawCall.Clipping.None || mClipping == UIDrawCall.Clipping.ConstrainButDontClip);			dc.sortingOrder = mSortingOrder;			// added by Clark			dc.sortingLayerName = mSortingLayerName;			// added end by Clark		}

using UnityEngine;using UnityEditor;using System.Collections.Generic;// added by Clarkusing System;using System.Reflection;using UnityEditorInternal;// added end by Clark

UIWidget.Pivot mDragPivot = UIWidget.Pivot.Center;	GUIStyle mStyle0 = null;	GUIStyle mStyle1 = null;	// added by Clark	string[] sortingLayerNames;	// added end by Clark

49行左右

protected override void OnEnable ()	{		base.OnEnable();		mPanel = target as UIPanel;		// added by Clark		sortingLayerNames = GetSortingLayerNames();		// added end by Clark	}

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GUI.changed = false;			int so = EditorGUILayout.IntField("Sort Order", mPanel.sortingOrder, GUILayout.Width(120f));			if (GUI.changed) mPanel.sortingOrder = so;			// added by Clark			int sortingLayerIndex = GetSortingLayerIndex(mPanel.sortingLayerName);			int newSortingLayerIndex = EditorGUILayout.Popup("Sorting Layer", sortingLayerIndex, sortingLayerNames);			if(sortingLayerIndex != newSortingLayerIndex)			{				mPanel.sortingLayerName = sortingLayerNames[newSortingLayerIndex];			}			// added end by Clark

785行左右，在文件最后

// added by Clark	string[] GetSortingLayerNames() 	{		Type t = typeof(InternalEditorUtility);		PropertyInfo prop = t.GetProperty("sortingLayerNames", BindingFlags.Static | BindingFlags.NonPublic);		return (string[])prop.GetValue(null, null);	}	int GetSortingLayerIndex(string layerName)	{		for(int i = 0; i < sortingLayerNames.Length; i++)		{			if(sortingLayerNames[i] == layerName)			{				return i;			}		}		return 0;	}	// added end by Clark}

完整的修改好的文件我放到我的资源里面了。