NGUI版本3.0.9 f4

脚本的作用：使用10个甚至更少的item模拟成百上千的item数据。在滑动过程中，如果拖到最后面的时候，会拿第一个过来补位。所以要正确的设置补位的那个item的数据。滑到最前面也是一样，用最后面的那个过来补位。

方法：

1、脚本放在Scroll View下面的UIGrid的那个物体上

2、UIScrollView的Restrict Within Panel勾选掉

3、Scroll View上面的UIPanel的Cull勾选上

4、你的每一个Item都放上一个UIWidget，调整到合适的大小（用它的Visiable）

5、仅仅是提供思路，具体每个Item的内容怎么更新什么的自己研究吧。

6、应该没问题了。有问题加群问。

附代码：

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
 
[RequireComponent(typeof(UIGrid))]
public class SZUILoopScrollView : MonoBehaviour {
 
    public string perfix = string.Empty;
    
    private List<UIWidget> itemList = new List<UIWidget>();
    private Vector4 posParam;
    private Transform cachedTransform;
    
    void Awake()
    {
        cachedTransform = this.transform;
        UIGrid grid = this.GetComponent<UIGrid>();
        float cellWidth = grid.cellWidth;
        float cellHeight = grid.cellHeight;
        posParam = new Vector4(cellWidth, cellHeight,
            grid.arrangement == UIGrid.Arrangement.Horizontal ? 1 : 0,
            grid.arrangement == UIGrid.Arrangement.Vertical ? 1 : 0);
    }
    
    void Start()
    {
        for (int i=0; i<cachedTransform.childCount; ++i)
        {
            Transform t = cachedTransform.GetChild(i);
            UIWidget uiw = t.GetComponent<UIWidget>();
            uiw.name = string.Format("{0}_{1:D3}", perfix, itemList.Count);
            itemList.Add(uiw);
        }
    }
    
    void LateUpdate()
    {
        if (itemList.Count > 1)
        {
            int sourceIndex = -1;
            int targetIndex = -1;
            int sign = 0;
            
            bool firstVislable = itemList[0].isVisible;
            bool lastVisiable = itemList[itemList.Count-1].isVisible;
            
            // if first and last both visiable or invisiable then return   
            if (firstVislable == lastVisiable)
            {
                return;
            }
            
            if (firstVislable)
            {
                // move last to first one
                sourceIndex = itemList.Count-1;
                targetIndex = 0;
                sign = -1;
            }
            else if (lastVisiable)
            {
                // move first to last one
                sourceIndex = 0;
                targetIndex = itemList.Count-1;
                sign = 1;
            }
            if (sourceIndex > -1)
            {
                UIWidget movedWidget = itemList[sourceIndex];
                Vector3 offset = new Vector3(sign*posParam.x * posParam.z, sign*posParam.y * posParam.w, 0);
                movedWidget.cachedTransform.localPosition = itemList[targetIndex].cachedTransform.localPosition + offset;
                // change item index
                itemList.RemoveAt(sourceIndex);
                itemList.Insert(targetIndex, movedWidget);
            }
        }
    }
}