unity 無限列表功能（水平方向滑動，豎直方向原理類似）

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);
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="rectTransform"></param>
        /// <param name="pos">世界座標的position</param>
        /// <returns></returns>
        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;
        }
    }

以上拓展方法是判斷兩個Recttransform類型的物體是否相交。

然後ScrollRec的滑動回調方法中更新UI位置，代碼如下

private void OnScrollRectValueChanged(Vector2 arg0)
        {
            Dictionary<int, DynamicRect> inOverlaps = new Dictionary<int, DynamicRect>();

            mRectMask = 遮罩物體的RectTransform.WorldRect();
            //m_DynamicRectDic這個字典保存的是你所有UI需要放置的位置數據，
            //判斷所有UI哪個是可見哪個不可見 ，保存起來
            foreach (DynamicRect dR in m_DynamicRectDic.Values)
            {
                tmpTra.localPosition = dR.localPos;
                //獲取每個位置UI的世界座標Rect
                Rect rect = m_LevelItemPrefabRT.WorldRect2(tmpTra.position);
                if (rect.Overlaps(mRectMask))
                {
                    inOverlaps.Add(dR.Index, dR);
                }
            }
            //m_LevelItemList是保存你實例化後的UI列表，比如你這個遮罩頁面最多顯示3個UI，你需要實例化4個UI，然後動態修改gameobject的顯示與隱藏
            int len = m_LevelItemList.Count;
            for (int i = 0; i < len; ++i)
            {
                //LevelItem是UI上掛載的腳本，用於更新UI界面的顯示和數據存儲的
                LevelItem item = m_LevelItemList[i];
                if (item.DRect != null && !inOverlaps.ContainsKey(item.DRect.Index))
                {
                    //item的DRect爲null時，隱藏物體，否則顯示物體
                    item.DRect = null;
                }
            }
            //判斷哪些可以重複利用的UI，然後賦予新的數據與位置
            foreach (DynamicRect dR in inOverlaps.Values)
            {
                if (GetDynmicItem(dR) == null)
                {
                    LevelItem item = GetNullDynmicItem();

                    if (item == null) continue;

                    item.DRect = dR;
                    //更新UI的位置和顯示（自己計算，每種顯示不一樣）
                    _UpdateChildTransformPos(item.gameObject, dR.Index);
                }
            }
        }

        /// <summary>
        /// 通過動態格子獲得動態渲染器
        /// </summary>
        /// <param name="rect"></param>
        /// <returns></returns>
        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;
        }
        /// <summary>
        /// 獲得待渲染的渲染器
        /// </summary>
        /// <returns></returns>
        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
    {
        /// <summary>
        /// 本地座標
        /// </summary>
        public Vector3 localPos;
        /// <summary>
        /// 格子索引
        /// </summary>
        public int Index;

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

參考鏈接：https://blog.csdn.net/u014621871/article/details/91380688