本站文章转载务必在明显处注明：原文链接 http://blog.csdn.net/cjsen/article/details/52489191
前言
在UGUI中并没有自带类似cocos2d-x里的列表控件TableView，只能ScrollView这种的滚动条，下面就自定义一个TableView。
正文
1，实现功能：列表中cell的重复利用，在列表滚动刷新中只改变cell的数据内容与位置 ，并不会一直加载新的cell，cell的最大数量只在于覆盖可视界面的高度
2，实现思路：利用UGUI的ScrollView，根据列表的可视高度计算需要多少个cell，在void onValueChanged(Vector2 value)方法，计算列表的滚动位置距离，计算并刷新cell的位置和数据
3，下面是实现的主要源码，不一一解释，文章后面会放出完整工程控件代码和使用示例
<span style="font-family:Menlo;"><span style="color:#333333;">using UnityEngine</span><span style="color:#333333;">;</span>
<span style="color:#333333;">using System</span><span style="color:#333333;">.</span><span style="color:#333333;">Collections</span><span style="color:#333333;">;</span></span>
using UnityEngine.UI;
using System.Collections.Generic;
using UnityEngine.EventSystems;
//列表排列方向
public enum TableDirection{
Horizontal, //水平
Vertical //直
}
public class UITableView : MonoBehaviour,IBeginDragHandler,IEndDragHandler,IDragHandler
{
TableCellWithShowedDelegate m_pTableCellWithShowedDelegate = null;//设置委托
float m_fCellHight; //行的高度
int m_iCellTotalNum; //行的总数量
int m_iCellPortNum; //可视行的数量
Vector2 m_pTableViewSize; //列表的宽高
Vector2 m_pContentViewSize; //列表内容的宽高
GameObject m_pScrollView; //列表Scroll控件
RectTransform m_pContentView; //列表内容
List<UITableViewCell> m_pCellViewList = null;//可视的行存储队列
//初始化数据
void init(Vector2 rectPos,Vector2 rectSize,Transform parent,TableDirection dir){
m_pCellViewList = new List<UITableViewCell> ();
GameObject _scrollViewPerfab = Resources.Load ("prefab/UITableView/ScrollView") as GameObject;
m_pScrollView = GameObject.Instantiate (_scrollViewPerfab) as GameObject;
m_pScrollView.transform.SetParent (parent);
m_pScrollView.transform.localScale = _scrollViewPerfab.transform.localScale;
m_pScrollView.transform.localPosition = rectPos;
m_pScrollView.GetComponent<RectTransform> ().sizeDelta = rectSize;//new Vector2 (540.0f, 640.0f);
m_pScrollView.GetComponent<ScrollRect>().onValueChanged.AddListener (onValueChanged);
m_pContentView = m_pScrollView.GetComponent<ScrollRect> ().content;
m_pTableViewSize = rectSize;
}
void onValueChanged(Vector2 value){
float _showStartY = m_pContentView.GetComponent<RectTransform> ().localPosition.y;
float _showEndY = _showStartY + m_pTableViewSize.y;
if (_showStartY < 0 || _showEndY > m_pContentViewSize.y) {
return;
}
int _listCount = m_pCellViewList.Count;
//先搜索列表上面有没有可显示的行
bool _bIsHaveCell = false;
for(int i = 0; i < _listCount; i++){
UITableViewCell _cellItem = m_pCellViewList [i];
float _cellUpPosY = System.Math.Abs(_cellItem.transform.localPosition.y) - m_fCellHight * 0.5f;
if(_cellUpPosY <= _showStartY ){
_bIsHaveCell = true;
break;
}
}
if (_bIsHaveCell == false) {
//计算出要显示的是哪一行，更新行
float _fTopIndex = (_showStartY/m_fCellHight)-(int)(_showStartY/m_fCellHight);
int _iTopIndex = (int)(_showStartY / m_fCellHight);
int _showTopIndex = _fTopIndex == 0.0f ? _iTopIndex : _iTopIndex + 1;
updateCellAtIndex (_showTopIndex-1);
} else {
//搜索列表下部分有没有可显示的行
bool _bBottomHaveCell = false;
for(int i = 0; i < _listCount; i ++){
UITableViewCell _cellItem = m_pCellViewList[i];
float _cellDownPosY = System.Math.Abs (_cellItem.transform.localPosition.y) + m_fCellHight * 0.5f;
if (_cellDownPosY >= _showEndY) {
_bBottomHaveCell = true;
break;
}
}
if (_bBottomHaveCell == false) {
//计算出要显示的是哪一行，更新行
float _fBottomIndex = (_showEndY/m_fCellHight)-(int)(_showEndY/m_fCellHight);
int _iBottomIndex = (int)(_showEndY / m_fCellHight);
int _showBottomIndex = _fBottomIndex == 0.0f ? _iBottomIndex : _iBottomIndex + 1;
updateCellAtIndex (_showBottomIndex-1);
}
}
}
//按索引获取更新行
void updateCellAtIndex(int idx){
bool _isHaveDeq = isHaveDequeueCell ();
if (_isHaveDeq == true) {
UITableViewCell _cell = tableDequeueCellIndex (idx);
if (m_pTableCellWithShowedDelegate != null) {
m_pTableCellWithShowedDelegate(_cell, idx, true);
}
}else{
UITableViewCell _cell = createTableCell (idx);
m_pCellViewList.Add (_cell);
if (m_pTableCellWithShowedDelegate != null) {
m_pTableCellWithShowedDelegate(_cell, idx, true);
}
}
}
void createCellItem(UITableViewCell tabelCell,int index, bool isNew){
GameObject _cell = null;
if (isNew == true) {
GameObject _cellPerfab = Resources.Load ("ListItemCell") as GameObject;
_cell = GameObject.Instantiate (_cellPerfab) as GameObject;
tabelCell.addViewCell (_cell);
} else {
_cell = tabelCell.getViewCell ();
}
}
UITableViewCell createTableCell(int index){
UITableViewCell _tableCell = UITableViewCell.createTableCell ();
_tableCell.transform.SetParent (m_pContentView.transform);
_tableCell.transform.localScale = m_pContentView.transform.localScale;
_tableCell.transform.localRotation = m_pContentView.transform.localRotation;
_tableCell.transform.localPosition = new Vector2 (_tableCell.transform.localPosition.x,positionWithIndex(index));
return _tableCell;
}
float positionWithIndex(int index){
float _cellPosY = -(m_fCellHight * 0.5f + m_fCellHight * index);
Debug.Log ("positionWithIndex:index="+index+" _cellPosY="+_cellPosY);
return _cellPosY;
}
//检测当前列表的滚动的位置中 列表上是否有已生成但在隐藏位置的行
bool isHaveDequeueCell(){
bool _bIsHaveDeqCell = false;
float _showStartY = m_pContentView.GetComponent<RectTransform> ().localPosition.y;
float _showEndY = _showStartY + m_pTableViewSize.y;
int _listCount = m_pCellViewList.Count;
for(int i = 0; i < _listCount; i++){
UITableViewCell _cellItem = m_pCellViewList [i];
float _cellDownPosY = System.Math.Abs (_cellItem.transform.localPosition.y) + m_fCellHight * 0.5f;
if (_cellDownPosY > _showEndY) {
_bIsHaveDeqCell = true;
break;
}
}
return _bIsHaveDeqCell;
}
//根据要显示的行索引，找出一个隐藏的行 并重新设置位置为要显示的行的位置并返回
UITableViewCell tableDequeueCellIndex(int idx){
UITableViewCell _pTableViewCell = null;
float _showStartY = m_pContentView.GetComponent<RectTransform> ().localPosition.y;
float _showEndY = _showStartY + m_pTableViewSize.y;
int _listCount = m_pCellViewList.Count;
//检测当前列表的滚动的位置中 列表上面是否有已生成但在隐藏位置的行
bool _bTopIsHaveDeqCell = false;
for(int i = 0; i < _listCount; i++){
UITableViewCell _cellItem = m_pCellViewList [i];
float _cellDownPosY = System.Math.Abs (_cellItem.transform.localPosition.y) - m_fCellHight * 0.5f;
if (_cellDownPosY < _showEndY-m_fCellHight) {
_bTopIsHaveDeqCell = true;
break;
}
}
int _iDequeueCellIndex = 0;
if (_bTopIsHaveDeqCell == true) {
//找出列表上面位置 处于隐藏位置的最顶的一行
for(int index = 1; index < _listCount; index++){
UITableViewCell _pHideCell = m_pCellViewList [_iDequeueCellIndex];
UITableViewCell _pTempCell = m_pCellViewList [index];
if (System.Math.Abs(_pTempCell.transform.localPosition.y) < System.Math.Abs(_pHideCell.transform.localPosition.y)){
_iDequeueCellIndex = index;
}
}
} else {
for (int i = 1; i < _listCount; i++) {
UITableViewCell _pHideCell = m_pCellViewList [_iDequeueCellIndex];
UITableViewCell _pTempCell = m_pCellViewList [i];
if (System.Math.Abs (_pTempCell.transform.localPosition.y) < System.Math.Abs (_pHideCell.transform.localPosition.y)) {
_iDequeueCellIndex = i;
}
}
}
float _cellPosY = -(m_fCellHight * 0.5f + m_fCellHight * idx);
m_pCellViewList[_iDequeueCellIndex].transform.localPosition = new Vector2 (m_pCellViewList[idx].transform.localPosition.x,_cellPosY);
_pTableViewCell = m_pCellViewList [_iDequeueCellIndex];
return _pTableViewCell;
}
//更新加载列表
public void reloadData(){
updateData ();
float _showStartY = m_pContentView.GetComponent<RectTransform> ().localPosition.y;
int _iFirstIndex = (int)(_showStartY / m_fCellHight);
int _showFirstIndex = _iFirstIndex == 0.0f ? _iFirstIndex : _iFirstIndex + 1;
for (int i = _showFirstIndex; i < _showFirstIndex+m_iCellPortNum; i++) {
updateCellAtIndex (i);
}
}
void updateData(){
//计算复用的cell的数量
float m_iPortNum = (m_pTableViewSize.y/m_fCellHight)-(int)(m_pTableViewSize.y/m_fCellHight);//取余
int m_iPortNum1 = (int)(m_pTableViewSize.y/m_fCellHight);
m_iCellPortNum = m_iPortNum == 0.0f ? m_iPortNum1 : m_iPortNum1+1;
if (m_iCellPortNum > m_iCellTotalNum) {
m_iCellPortNum = m_iCellTotalNum;
}
m_pContentViewSize.x = m_pTableViewSize.x;
m_pContentViewSize.y = m_iCellTotalNum * m_fCellHight;
m_pContentView.GetComponent<RectTransform> ().sizeDelta = m_pContentViewSize;
}
public void OnDrag (PointerEventData eventData){
// Debug.Log ("开始拖动pressPosition="+eventData.pressPosition+"position="+eventData.position);
}
public void OnBeginDrag (PointerEventData eventData){
// Debug.Log ("开始拖动pressPosition="+eventData.pressPosition+"position="+eventData.position);
}
public void OnEndDrag (PointerEventData eventData){
// Debug.Log ("结束拖动pressPosition="+eventData.pressPosition+"position="+eventData.position);
}
//获取和设置行数量
public void setCellTotalNum(int num){
m_iCellTotalNum = num;
}
public float getCellTotalNum(){
return m_iCellTotalNum;
}
//获取和设置行的高度
public void setCellHight(float h){
m_fCellHight = h;
}
public float getCellHight(){
return m_fCellHight;
}
public void setTableCellWithShowedDelegate(TableCellWithShowedDelegate del){
m_pTableCellWithShowedDelegate = del;
}
public TableCellWithShowedDelegate getTableCellWithShowedDelegate(){
return m_pTableCellWithShowedDelegate;
}
// Use this for initialization
void Start ()
{
}
//公共方法
public static UITableView createTable(Vector2 rectPos,Vector2 rectSize,
Transform parent,TableDirection dir = TableDirection.Vertical){
GameObject _object = new GameObject ();
UITableView _table = null;
if (_object != null) {
// _object.name = "UITableView";
_table = _object.AddComponent (typeof(UITableView)) as UITableView;
_table.init (rectPos, rectSize, parent, dir);
} else {
Debug.Log ("出错了");
}
return _table;
}
public delegate void TableCellWithShowedDelegate (UITableViewCell cell,int index, bool isNew);
}