unity 无限列表功能（水平方向滑动，竖直方向原理类似）

public static class RectTransformExtensions
    {
        public static bool Overlaps(this RectTransform a, RectTransform b)
        {
            return a.WorldRect().Overlaps(b.WorldRect());
        }
        public static bool Overlaps(this RectTransform a, RectTransform b, bool allowInverse)
        {
            return a.WorldRect().Overlaps(b.WorldRect(), allowInverse);
        }

        public static Rect WorldRect(this RectTransform rectTransform)
        {
            Vector2 sizeDelta = rectTransform.sizeDelta;
            float rectTransformWidth = sizeDelta.x * rectTransform.lossyScale.x;
            float rectTransformHeight = sizeDelta.y * rectTransform.lossyScale.y;

            Vector3 position = rectTransform.position;

            return new Rect(
                position.x - rectTransformWidth * rectTransform.pivot.x,
                position.y - rectTransformHeight * rectTransform.pivot.y,
                rectTransformWidth,
                rectTransformHeight);
        }
        /// 

        /// 
        /// 
        /// 
        /// 世界坐标的position
        /// 
        public static Rect WorldRect2(this RectTransform rectTransform, Vector3 pos)
        {
            Rect rect = new Rect();
            Vector2 sizeDelta = rectTransform.sizeDelta;
            float rectTransformWidth = sizeDelta.x * rectTransform.lossyScale.x;
            float rectTransformHeight = sizeDelta.y * rectTransform.lossyScale.y;

            Vector3 position = pos;

            rect.x = position.x - rectTransformWidth * rectTransform.pivot.x;
            rect.y = position.y - rectTransformHeight * rectTransform.pivot.y;
            rect.width = rectTransformWidth;
            rect.height = rectTransformHeight;

            return rect;
        }
    }

以上拓展方法是判断两个Recttransform类型的物体是否相交。

然后ScrollRec的滑动回调方法中更新UI位置，代码如下

private void OnScrollRectValueChanged(Vector2 arg0)
        {
            Dictionary inOverlaps = new Dictionary();

            mRectMask = 遮罩物体的RectTransform.WorldRect();
            //m_DynamicRectDic这个字典保存的是你所有UI需要放置的位置数据，
            //判断所有UI哪个是可见哪个不可见 ，保存起来
            foreach (DynamicRect dR in m_DynamicRectDic.Values)
            {
                tmpTra.localPosition = dR.localPos;
                //获取每个位置UI的世界坐标Rect
                Rect rect = m_LevelItemPrefabRT.WorldRect2(tmpTra.position);
                if (rect.Overlaps(mRectMask))
                {
                    inOverlaps.Add(dR.Index, dR);
                }
            }
            //m_LevelItemList是保存你实例化后的UI列表，比如你这个遮罩页面最多显示3个UI，你需要实例化4个UI，然后动态修改gameobject的显示与隐藏
            int len = m_LevelItemList.Count;
            for (int i = 0; i < len; ++i)
            {
                //LevelItem是UI上挂载的脚本，用于更新UI界面的显示和数据存储的
                LevelItem item = m_LevelItemList[i];
                if (item.DRect != null && !inOverlaps.ContainsKey(item.DRect.Index))
                {
                    //item的DRect为null时，隐藏物体，否则显示物体
                    item.DRect = null;
                }
            }
            //判断哪些可以重复利用的UI，然后赋予新的数据与位置
            foreach (DynamicRect dR in inOverlaps.Values)
            {
                if (GetDynmicItem(dR) == null)
                {
                    LevelItem item = GetNullDynmicItem();

                    if (item == null) continue;

                    item.DRect = dR;
                    //更新UI的位置和显示（自己计算，每种显示不一样）
                    _UpdateChildTransformPos(item.gameObject, dR.Index);
                }
            }
        }

        /// 

        /// 通过动态格子获得动态渲染器
        /// 
        /// 
        /// 
        private LevelItem GetDynmicItem(DynamicRect rect)
        {
            int len = m_LevelItemList.Count;
            for (int i = 0; i < len; ++i)
            {
                LevelItem item = m_LevelItemList[i];
                if (item.DRect == null)
                    continue;
                if (rect.Index == item.DRect.Index)
                    return item;
            }
            return null;
        }
        /// 

        /// 获得待渲染的渲染器
        /// 
        /// 
        private LevelItem GetNullDynmicItem()
        {
            int len = m_LevelItemList.Count;
            for (int i = 0; i < len; ++i)
            {
                LevelItem item = m_LevelItemList[i];
                if (item.DRect == null)
                    return item;
            }

            return null;
        }

    public class DynamicRect
    {
        /// 

        /// 本地坐标
        /// 
        public Vector3 localPos;
        /// 

        /// 格子索引
        /// 
        public int Index;

        public DynamicRect(int index, Vector3 localPos)
        {
            this.Index = index;
            this.localPos = localPos;
        }
    }

参考链接：https://blog.csdn.net/u014621871/article/details/91380688