【Unity3D】无限循环列表（扩展版）

  基础版：【Unity技术分享】UGUI之ScrollRect优化_ugui scrollrect 优化-CSDN博客

using UnityEngine;
using UnityEngine.UI;
using System.Collections.Generic;public delegate void OnBaseLoopListItemCallback(GameObject cell, int index);
public class BaseLoopList : MonoBehaviour
{public int m_Row = 1; //排public bool m_IsVertical = true;public float m_SpacingX = 0f; //间距public float m_SpacingY = 0f; //间距public GameObject m_CellGameObject; //指定的cellprivate Dictionary<GameObject, int> m_GameObjectNumDict;//-> 回调相关        public event OnBaseLoopListItemCallback onItemShow; //Lua 回调public event OnBaseLoopListItemCallback onItemHide; //Lua 回调protected RectTransform rectTrans;protected float m_PlaneWidth;protected float m_PlaneHeight;protected float m_ContentWidth;protected float m_ContentHeight;protected float m_CellObjectWidth;protected float m_CellObjectHeight;protected GameObject m_Content;protected RectTransform m_ContentRectTrans;private bool m_isInited = false;//记录 物体的坐标 和 物体 protected struct CellInfo{public Vector3 pos;public GameObject obj;};protected CellInfo[] m_CellInfos;protected bool m_IsInited = false;protected ScrollRect m_ScrollRect;protected int m_MaxCount = -1; //列表数量protected int m_MinIndex = -1;protected int m_MaxIndex = -1;protected bool m_IsClearList = false; //是否清空列表protected Vector4 m_Padding = Vector4.zero; //(left,top,right,bottom) 左,上 偏移Item（左上角为锚点) 右,下 扩大Content(宽度和高度)//c# 初始化public virtual void Init(){if (m_isInited)return;m_isInited = true;m_GameObjectNumDict = new Dictionary<GameObject, int>();m_Content = this.GetComponent<ScrollRect>().content.gameObject;if (m_CellGameObject == null){//m_CellGameObject = m_Content.transform.GetChild(0).gameObject;Debug.LogError("m_CellGameObject 不能为 null");}/* Cell 处理 *///m_CellGameObject.transform.SetParent(m_Content.transform.parent, false);//SetPoolsObj(m_CellGameObject);RectTransform cellRectTrans = m_CellGameObject.GetComponent<RectTransform>();cellRectTrans.pivot = new Vector2(0f, 1f);CheckAnchor(cellRectTrans);cellRectTrans.anchoredPosition = Vector2.zero;//记录 Cell 信息m_CellObjectHeight = cellRectTrans.rect.height;m_CellObjectWidth = cellRectTrans.rect.width;//记录 Plane 信息rectTrans = GetComponent<RectTransform>();Rect planeRect = rectTrans.rect;m_PlaneHeight = planeRect.height;m_PlaneWidth = planeRect.width;//记录 Content 信息m_ContentRectTrans = m_Content.GetComponent<RectTransform>();Rect contentRect = m_ContentRectTrans.rect;SetContentHeight(contentRect.height);SetContentWidth(contentRect.width);m_ContentRectTrans.pivot = new Vector2(0f, 1f);//m_ContentRectTrans.sizeDelta = new Vector2 (planeRect.width, planeRect.height);//m_ContentRectTrans.anchoredPosition = Vector2.zero;CheckAnchor(m_ContentRectTrans);m_ScrollRect = this.GetComponent<ScrollRect>();m_ScrollRect.onValueChanged.RemoveAllListeners();//添加滑动事件m_ScrollRect.onValueChanged.AddListener(delegate (Vector2 value) { ScrollRectListener(value); });}public virtual void Destroy(){if (m_CellInfos != null){for (int i = 0; i < m_CellInfos.Length; i++){SetPoolsObj(m_CellInfos[i].obj);m_CellInfos[i].obj = null;}}m_GameObjectNumDict.Clear();}private void DisposeAll(){m_Padding = Vector4.zero;onItemShow = null;onItemHide = null;if (poolsObj != null){foreach (var v in poolsObj){if (v != null){GameObject.Destroy(v);}}poolsObj = null;}if (m_CellInfos != null){foreach (var v in m_CellInfos){if (v.obj != null){GameObject.Destroy(v.obj);}}m_CellInfos = null;}}//检查 Anchor 是否正确private void CheckAnchor(RectTransform rectTrans){if (m_IsVertical){if (!((rectTrans.anchorMin == new Vector2(0, 1) && rectTrans.anchorMax == new Vector2(0, 1)) ||(rectTrans.anchorMin == new Vector2(0, 1) && rectTrans.anchorMax == new Vector2(1, 1)))){rectTrans.anchorMin = new Vector2(0, 1);rectTrans.anchorMax = new Vector2(1, 1);}}else{if (!((rectTrans.anchorMin == new Vector2(0, 1) && rectTrans.anchorMax == new Vector2(0, 1)) ||(rectTrans.anchorMin == new Vector2(0, 0) && rectTrans.anchorMax == new Vector2(0, 1)))){rectTrans.anchorMin = new Vector2(0, 0);rectTrans.anchorMax = new Vector2(0, 1);}}}public void SetPadding(float left, float top, float right, float bottom){m_Padding = new Vector4(left, top, right, bottom);SetContentWidth(m_ContentWidth);SetContentHeight(m_ContentHeight);}private float GetPaddingX(){return m_Padding.x;}private float GetPaddingY(){return m_Padding.y;}private float GetExpandWidth(){return m_Padding.z;}private float GetExpandHeight(){return m_Padding.w;}public void SetContentWidth(float value){m_ContentWidth = value + GetPaddingX() + GetExpandWidth();m_ContentWidth = m_ContentWidth < rectTrans.rect.width ? rectTrans.rect.width : m_ContentWidth;}public void SetContentHeight(float value){m_ContentHeight = value + GetPaddingY() + GetExpandHeight();m_ContentHeight = m_ContentHeight < rectTrans.rect.height ? rectTrans.rect.height : m_ContentHeight;}public virtual void SetCount(int num){m_MinIndex = -1;m_MaxIndex = -1;//-> 计算 Content 尺寸if (m_IsVertical){float contentSize = (m_SpacingY + m_CellObjectHeight) * Mathf.CeilToInt((float)num / m_Row);SetContentHeight(contentSize);SetContentWidth(m_ContentRectTrans.rect.width);m_ContentRectTrans.sizeDelta = new Vector2(m_ContentWidth, m_ContentHeight);if (num != m_MaxCount){m_ContentRectTrans.anchoredPosition = new Vector2(m_ContentRectTrans.anchoredPosition.x, 0);}}else{float contentSize = (m_SpacingX + m_CellObjectWidth) * Mathf.CeilToInt((float)num / m_Row);SetContentWidth(contentSize);SetContentHeight(m_ContentRectTrans.rect.height);m_ContentRectTrans.sizeDelta = new Vector2(m_ContentWidth, m_ContentHeight);if (num != m_MaxCount){m_ContentRectTrans.anchoredPosition = new Vector2(0, m_ContentRectTrans.anchoredPosition.y);}}//-> 计算 开始索引int lastEndIndex = 0;//-> 过多的物体 扔到对象池 ( 首次调 ShowList函数时 则无效 )if (m_IsInited){lastEndIndex = num - m_MaxCount > 0 ? m_MaxCount : num;lastEndIndex = m_IsClearList ? 0 : lastEndIndex;int count = m_IsClearList ? m_CellInfos.Length : m_MaxCount;for (int i = lastEndIndex; i < count; i++){if (m_CellInfos[i].obj != null){SetPoolsObj(m_CellInfos[i].obj);if (onItemHide != null){int objNum = 0;m_GameObjectNumDict.TryGetValue(m_CellInfos[i].obj, out objNum);onItemHide.Invoke(m_CellInfos[i].obj, objNum);}m_CellInfos[i].obj = null;}}}//-> 以下四行代码 在for循环所用CellInfo[] tempCellInfos = m_CellInfos;m_CellInfos = new CellInfo[num];//-> 1: 计算 每个Cell坐标并存储 2: 显示范围内的 Cellfor (int i = 0; i < num; i++){// * -> 存储 已有的数据 ( 首次调 ShowList函数时 则无效 )if (m_MaxCount != -1 && i < lastEndIndex){CellInfo tempCellInfo = tempCellInfos[i];//-> 计算是否超出范围float rPos = m_IsVertical ? tempCellInfo.pos.y : tempCellInfo.pos.x;if (!IsOutRange(rPos)){//-> 记录显示范围中的 首位index 和 末尾indexm_MinIndex = m_MinIndex == -1 ? i : m_MinIndex; //首位indexm_MaxIndex = i; // 末尾indexif (tempCellInfo.obj == null){tempCellInfo.obj = GetPoolsObj();}tempCellInfo.obj.transform.GetComponent<RectTransform>().anchoredPosition = tempCellInfo.pos;if (!m_GameObjectNumDict.ContainsKey(tempCellInfo.obj)){m_GameObjectNumDict.Add(tempCellInfo.obj, i);}else{m_GameObjectNumDict[tempCellInfo.obj] = i;}tempCellInfo.obj.SetActive(true);//-> 回调 Lua 函数Func(tempCellInfo.obj);}else{if (tempCellInfo.obj != null){SetPoolsObj(tempCellInfo.obj);if (onItemHide != null){int objNum = 0;m_GameObjectNumDict.TryGetValue(tempCellInfo.obj, out objNum);onItemHide.Invoke(tempCellInfo.obj, objNum);}tempCellInfo.obj = null;}}m_CellInfos[i] = tempCellInfo;continue;}CellInfo cellInfo = new CellInfo();float pos = 0;  //坐标( isVertical ? 记录Y : 记录X )float rowPos = 0; //计算每排里面的cell 坐标// * -> 计算每个Cell坐标if (m_IsVertical){pos = m_CellObjectHeight * Mathf.FloorToInt(i / m_Row) + m_SpacingY * Mathf.FloorToInt(i / m_Row);rowPos = m_CellObjectWidth * (i % m_Row) + m_SpacingX * (i % m_Row);cellInfo.pos = new Vector3(rowPos + GetPaddingX(), -pos - GetPaddingY(), 0);}else{pos = m_CellObjectWidth * Mathf.FloorToInt(i / m_Row) + m_SpacingX * Mathf.FloorToInt(i / m_Row);rowPos = m_CellObjectHeight * (i % m_Row) + m_SpacingY * (i % m_Row);cellInfo.pos = new Vector3(pos + GetPaddingX(), -rowPos - GetPaddingY(), 0);}//-> 计算是否超出范围float cellPos = m_IsVertical ? cellInfo.pos.y : cellInfo.pos.x;if (IsOutRange(cellPos)){cellInfo.obj = null;m_CellInfos[i] = cellInfo;continue;}//-> 记录显示范围中的 首位index 和 末尾indexm_MinIndex = m_MinIndex == -1 ? i : m_MinIndex; //首位indexm_MaxIndex = i; // 末尾index//-> 取或创建 CellGameObject cell = GetPoolsObj();cell.transform.GetComponent<RectTransform>().anchoredPosition = cellInfo.pos;if (!m_GameObjectNumDict.ContainsKey(cell.gameObject)){m_GameObjectNumDict.Add(cell.gameObject, i);}else{m_GameObjectNumDict[cell.gameObject] = i;}//-> 存数据cellInfo.obj = cell;m_CellInfos[i] = cellInfo;//-> 回调 Lua 函数Func(cell);}m_MaxCount = num;m_IsInited = true;}//实时刷新列表时用public virtual void UpdateList(){NormalPerformanceMode();}//刷新某一项public void UpdateCell(int index){CellInfo cellInfo = m_CellInfos[index - 1];if (cellInfo.obj != null){float rangePos = m_IsVertical ? cellInfo.pos.y : cellInfo.pos.x;if (!IsOutRange(rangePos)){Func(cellInfo.obj);}}}// 更新滚动区域的大小public void UpdateSize(){Rect rect = GetComponent<RectTransform>().rect;m_PlaneHeight = rect.height;m_PlaneWidth = rect.width;}//滑动事件protected virtual void ScrollRectListener(Vector2 value){NormalPerformanceMode(); //普通性能模式}//普通性能模式private void NormalPerformanceMode(){if (m_CellInfos == null)return;//检查超出范围for (int i = 0, length = m_CellInfos.Length; i < length; i++){CellInfo cellInfo = m_CellInfos[i];GameObject obj = cellInfo.obj;Vector3 pos = cellInfo.pos;float rangePos = m_IsVertical ? pos.y : pos.x;//判断是否超出显示范围if (IsOutRange(rangePos)){//把超出范围的cell 扔进 poolsObj里if (obj != null){SetPoolsObj(obj);if (onItemHide != null){int objNum = 0;m_GameObjectNumDict.TryGetValue(obj, out objNum);onItemHide.Invoke(obj, objNum);}m_CellInfos[i].obj = null;}}else{if (obj == null){//优先从 poolsObj中 取出 （poolsObj为空则返回 实例化的cell）GameObject cell = GetPoolsObj();cell.transform.localPosition = pos;if (!m_GameObjectNumDict.ContainsKey(cell.gameObject)){m_GameObjectNumDict.Add(cell.gameObject, i);}else{m_GameObjectNumDict[cell.gameObject] = i;}m_CellInfos[i].obj = cell;Func(cell);}}}}//判断是否超出显示范围protected bool IsOutRange(float pos){Vector3 listP = m_ContentRectTrans.anchoredPosition;if (m_IsVertical){if (pos + listP.y > m_CellObjectHeight || pos + listP.y < -rectTrans.rect.height){return true;}}else{if (pos + listP.x < -m_CellObjectWidth || pos + listP.x > rectTrans.rect.width){return true;}}return false;}//对象池 机制  (存入， 取出) cellprotected Stack<GameObject> poolsObj = new Stack<GameObject>();//取出 cellprotected virtual GameObject GetPoolsObj(){GameObject cell = null;if (poolsObj.Count > 0){cell = poolsObj.Pop();}if (cell == null){cell = Instantiate(m_CellGameObject) as GameObject;}cell.transform.SetParent(m_Content.transform);cell.transform.localScale = Vector3.one;SetActive(cell, true);return cell;}//存入 cellprotected virtual void SetPoolsObj(GameObject cell){if (cell != null){poolsObj.Push(cell);SetActive(cell, false);}}//回调protected void Func(GameObject selectObject){int num = 0;m_GameObjectNumDict.TryGetValue(selectObject, out num);onItemShow?.Invoke(selectObject, num);}void SetActive(GameObject cell, bool isShow){cell.SetActive(isShow);}protected void OnDestroy(){DisposeAll();}
}

其他2个使用案例C#脚本代码：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;public class LoopListManager : MonoBehaviour
{public BaseLoopList baseLoopList;private Dictionary<int, BaseLoopListItem> loopListItemDict;void Start(){baseLoopList.onItemShow += OnShow;baseLoopList.onItemHide += OnHide;loopListItemDict = new Dictionary<int, BaseLoopListItem>();baseLoopList.Init();//baseLoopList.SetPadding(20, 30, 0, 0);//支持Padding四个方向的偏移baseLoopList.SetCount(50);}private BaseLoopListItem GetItem(GameObject cell, int index){BaseLoopListItem item;loopListItemDict.TryGetValue(index, out item);if (item == null){item = cell.GetComponent<BaseLoopListItem>();loopListItemDict.Add(index, item);}return item;}public void OnShow(GameObject cell, int index){Debug.Log("Show:" + index);BaseLoopListItem item = GetItem(cell, index);item.OnShow(index);}public void OnHide(GameObject cell, int index){Debug.Log("Hide:" + index);BaseLoopListItem item = GetItem(cell, index);item.OnHide(index);//注意: 无限循环列表的Item是重复利用的物体，逻辑上Hide之后必须从缓存中移除,否则会一定会出现Item刷新异常;//原因: 若不移除会出现Show(index物体)时会拿到一个不正确位置的物体, 甚至很大可能是一个已显示中的物体(形成覆盖效果)loopListItemDict.Remove(index);}
}

using UnityEngine;
using TMPro;
public class BaseLoopListItem : MonoBehaviour
{public TextMeshProUGUI text;public void OnShow(int index){text.text = index.ToString();}public void OnHide(int index){text.text = "";}
}

注意事项：无限循环列表的Item物体是重复利用的，因此OnHide回调后必须将传递进来的物体所有相关的缓存引用清空，例如案例是将其从字典移除loopListItemDict.Remove(index);

Content选择左上角锚点（看情况可选其他，但不要用自适应stretch） 以及不要挂任何自动控制布局组件，如：VerticalLayoutGroup、HorizontalLayoutGroup、GridLayoutGroup、ContentSizeFitter等...（因为会破坏无限循环列表对Content的控制）