一、先看下效果
Prefab结构
二、实现思路：
1、prefab上的Panel层级设置成较高
2、背景由5个UISprite拼接起来的，4个（L,R,U,D）当作遮罩，1个镂空(Hollow)当作点击触发（全部都有BoxCollider，并且都生效，有人会问这不就把后面的按钮也给拦截住了，后面会说为什么要这样）
3、4个遮罩的大小由Holow大小决定
4、Hollow绑定一个点击事件ClickCenter （后面代码里有）
三、关键部分：
这里解释为什么上面要把Hollow也带上BoxCollider，目的是修正点击位置，只要是点Hollow上，就让NGUI只相应点击在Hollow中心点后面的第一个UIWidget，这样就可以避免因为点不准，拖拽的其他问题
如图，只要我点在篮筐里，就只响应红点下面的第一个控件
四、代码
其实就是NGUI的点击响应代码，位置传入的是Hollow的位置
using System;
using UnityEngine;
using System.Collections;
using System.Collections.Generic; public class NewbieGuide : MonoBehaviour
{ public Transform Hollow; bool IsVisible(Vector3 worldPoint, GameObject go)
{
UIPanel panel = NGUITools.FindInParents<UIPanel>(go); while (panel != null)
{
if (!panel.IsVisible(worldPoint)) return false;
panel = panel.parentPanel;
}
return true;
} struct DepthEntry
{
public int depth;
public RaycastHit hit;
public Vector3 point;
public GameObject go;
} #if UNITY_FLASH
static bool IsVisible (DepthEntry de)
#else
static bool IsVisible(ref DepthEntry de)
#endif
{
UIPanel panel = NGUITools.FindInParents<UIPanel>(de.go); while (panel != null)
{
if (!panel.IsVisible(de.point)) return false;
panel = panel.parentPanel;
}
return true;
} void Notify(GameObject go, string funcName, object obj)
{
if (NGUITools.GetActive(go))
{
go.SendMessage(funcName, obj, SendMessageOptions.DontRequireReceiver);
}
} public void ClickCenter()
{
DepthEntry mHit = new DepthEntry();
BetterList<DepthEntry> mHits = new BetterList<DepthEntry>(); UICamera cam = UICamera.current; UIEventTrigger.current = null; // Convert to view space
var currentCamera = cam.cachedCamera; // Cast a ray into the screen
var p = Hollow.transform.position;
p.z = currentCamera.nearClipPlane;
Ray ray = new Ray(p, Vector3.forward); // Raycast into the screen
int mask = currentCamera.cullingMask & (int)cam.eventReceiverMask;
float dist = (cam.rangeDistance > 0f) ? cam.rangeDistance : currentCamera.farClipPlane - currentCamera.nearClipPlane; RaycastHit[] hits = Physics.RaycastAll(ray, dist, mask); if (hits.Length > )
{
for (int b = ; b < hits.Length; ++b)
{
GameObject go = hits[b].collider.gameObject; if (go == Hollow.gameObject)
continue; UIWidget w = go.GetComponent<UIWidget>(); if (w != null)
{
if (!w.isVisible) continue;
if (w.hitCheck != null && !w.hitCheck(hits[b].point)) continue;
}
else
{
UIRect rect = NGUITools.FindInParents<UIRect>(go);
if (rect != null && rect.finalAlpha < 0.001f) continue;
} mHit.depth = NGUITools.CalculateRaycastDepth(go); if (mHit.depth != int.MaxValue)
{
mHit.hit = hits[b];
mHit.point = hits[b].point;
mHit.go = hits[b].collider.gameObject;
mHits.Add(mHit);
}
} mHits.Sort(delegate(DepthEntry r1, DepthEntry r2) { return r2.depth.CompareTo(r1.depth); }); for (int b = ; b < mHits.size; ++b)
{
#if UNITY_FLASH
if (IsVisible(mHits.buffer[b]))
#else
if (IsVisible(ref mHits.buffer[b]))
#endif
{
Notify(mHits.buffer[b].go, "OnClick", null);
return;
}
}
mHits.Clear();
}
else if (hits.Length == )
{
GameObject go = hits[].collider.gameObject; if (go == Hollow.gameObject)
return; UIWidget w = go.GetComponent<UIWidget>(); if (w != null)
{
if (!w.isVisible) return;
if (w.hitCheck != null && !w.hitCheck(hits[].point)) return;
}
else
{
UIRect rect = NGUITools.FindInParents<UIRect>(go);
if (rect != null && rect.finalAlpha < 0.001f) return;
} if (IsVisible(hits[].point, hits[].collider.gameObject))
{
Notify(hits[].collider.gameObject, "OnClick", null);
return;
}
} } }