unity如何实现翻页按钮功能

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Events;
using UnityEngine.UI;
/// 

/// 分页按钮面板控制器
/// 
public class PageBtnPanelC : MonoBehaviour {
 private HorizontalLayoutGroup self_HLG;
 /// 

 /// 上一页按钮
 /// 
 private Button lastPageBtn;
 /// 

 /// 下一页按钮
 /// 
 private Button nextPageBtn;
 /// 

 /// 页数的父物体
 /// 
 private RectTransform pageBtnParent;
 private HorizontalLayoutGroup pageBtnParent_HLG;
 /// 

 /// 上一页按钮点击事件
 /// 
 private UnityAction lastPageBtnEvent;
 /// 

 /// 下一页按钮点击事件
 /// 
 private UnityAction nextPageBtnEvent;
 /// 

 /// 当前显示页面的下标
 /// 
 private int _currentShowPageIndex = 1;
 public int CurrentShowPageIndex {
  get {
   return _currentShowPageIndex;
  }
  set {
   _currentShowPageIndex = value;
  }
 }
 /// 

 /// 总的页面数
 /// 
 private int totalPageNumber = 0;
 /// 

 /// 显示按钮的个数 奇数个
 /// 
 [Header("必须是奇数个，且小于总页数")]
 private int _showBtnCount = 5;
 public int ShowBtnCount {
  get {
   if (_showBtnCount > totalPageNumber) {
    _showBtnCount = totalPageNumber;
   }
 
   return _showBtnCount;
  }
  set {
   if (value % 2 == 0)
   {
    _showBtnCount = value - 1;
   }
   else {
    _showBtnCount = value;
   }
  }
 }
 /// 

 /// 页数按钮 预设体
 /// 
 public GameObject btnPrefabs;
 /// 

 /// 页数按钮 存放list
 /// 
 public List pbcList;
 
 private void Start()
 {
  Init();
  Set(14, 9, (index1) =>
  {
   Debug.Log("当前显示第：" + CurrentShowPageIndex + "页");
  }, (index2) =>
  {
   Debug.Log("当前显示第：" + CurrentShowPageIndex + "页");
  }, (_pageIndex, _pbc) =>
  {
   Debug.Log("当前显示第：" + CurrentShowPageIndex + "页");
  });
 }
 /// 

 /// 改变显示的状态
 /// 
 void ChangeShowState() {
  int _showBtnCount = ShowBtnCount;
  /*
   判断是否在可更新范围内,如果在更新范围内，则将CurrentShowPageIndex设置为中心位置的按钮
   eg:假设总共有10页(totalPageNumber = 10)，显示按钮的个数为7（ShowBtnCount = 7）
   则应该在 (ShowBtnCount / 2 + 1) = 4 到 totalPageNumber - ShowBtnCount / 2 = 7 之间设置
   如果CurrentShowPageIndex = 5或6
   则应该这样显示  1.. 3 4 5 6 7 ..10
   如果不在更新范围内，
   如果CurrentShowPageIndex = 1或2或3或4  则应该这样显示： 1 2 3 4 5 6 ..10
   如果如果CurrentShowPageIndex = 7或8或9或10 则应该这样显示 1.. 5 6 7 8 9 10
   */
  if (CurrentShowPageIndex >= (ShowBtnCount / 2 + 1) && CurrentShowPageIndex <= (totalPageNumber - ShowBtnCount / 2))
  {
   int _showBtnCount2 = _showBtnCount - 2;
   _showBtnCount2 /= 2;
 
   //判断起始下标
   int startIndex = CurrentShowPageIndex - _showBtnCount2;
   int endIndex = CurrentShowPageIndex + _showBtnCount2;
 
   //防止超出
   if (startIndex <= 1)
   {
    startIndex = 2;
   }
   //防止超出
   if (endIndex >= totalPageNumber)
   {
    endIndex = totalPageNumber - 1;
   }
 
   //计算中心位置按钮的下标 因为showBtnCount不定
   int centerIndex = ShowBtnCount / 2;
 
   pbcList[centerIndex].Set(CurrentShowPageIndex);
 
   //循环设置前面一部分按钮信息
   for (int i = 1; i < centerIndex; i++)
   {
    pbcList[i].Set(startIndex++);
   }
 
   //循环设置后面一部分按钮信息
   for (int i = centerIndex + 1; i < ShowBtnCount - 1; i++)
   {
    startIndex++;
    pbcList[i].Set(startIndex);
   }
  }
  else {
   //如果点击的是小于等于4的按钮下标
   if (CurrentShowPageIndex < (ShowBtnCount / 2 + 1))
   {
    for (int i = 0; i < ShowBtnCount - 1; i++) {
     pbcList[i].Set(i+1);
    }
   }//如果点击的事大于等于7的按钮下标
   else if (CurrentShowPageIndex > (totalPageNumber - ShowBtnCount / 2)) {
 
    int startNumber = totalPageNumber - ShowBtnCount + 2;
 
    for (int i = 1; i < ShowBtnCount; i++) {
     pbcList[i].Set(startNumber++);
    }
   }
  }
 
  /*
   判断总显示页数是否大于显示页数
   以防止出现这种效果：
   例如：totalPageNumber = 7，ShowBtnCount =7
   防止出现的效果：1 2 3 4 5 6 ..7 和 1.. 2 3 4 5 6 7
   应该出现的效果：1 2 3 4 5 6 7
   */
  if (totalPageNumber > ShowBtnCount){
   _showBtnCount -= 2;
   _showBtnCount /= 2;
   if (CurrentShowPageIndex - _showBtnCount - 1 > 1)
   {
    pbcList[0].Set(1, "1..");
   }
   else
   {
    pbcList[0].Set(1);
   }
   if (CurrentShowPageIndex + _showBtnCount + 1 < totalPageNumber)
   {
    pbcList[ShowBtnCount - 1].Set(totalPageNumber, ".." + totalPageNumber);
   }
   else
   {
    pbcList[ShowBtnCount - 1].Set(totalPageNumber);
   }
  }
 }
 
 private bool isInit = false;
 public void Init() {
  if (isInit)
   return;
  isInit = true;
 
  pbcList = new List();
 
  self_HLG = transform.GetComponent();
 
  pageBtnParent = transform.Find("PageIndexParent") as RectTransform;
  pageBtnParent_HLG = pageBtnParent.GetComponent();
 
  lastPageBtn = transform.Find("LastPageBtn").GetComponent();
  lastPageBtn.onClick.AddListener(()=> {
   if (totalPageNumber <= 0)
    return;
 
   if (CurrentShowPageIndex > 1) {
    CurrentShowPageIndex--;
   }
 
   ResetPageBtnState();
 
   ChangeShowState();
 
   PageBtnC pbc = GetPBCFromIndex(CurrentShowPageIndex);
   if (pbc != null) {
    pbc.SetHighlightColor();
   }
 
   if (lastPageBtnEvent != null)
   {
    lastPageBtnEvent(CurrentShowPageIndex);
   }
  });
 
  nextPageBtn = transform.Find("NextPageBtn").GetComponent();
  nextPageBtn.onClick.AddListener(()=> {
   if (totalPageNumber <= 0)
    return;
 
   if (CurrentShowPageIndex < totalPageNumber) {
    CurrentShowPageIndex++;
   }
 
   ResetPageBtnState();
 
   ChangeShowState();
   
   PageBtnC pbc = GetPBCFromIndex(CurrentShowPageIndex);
   if (pbc != null)
   {
    pbc.SetHighlightColor();
   }
 
   if (nextPageBtnEvent != null)
   {
    nextPageBtnEvent(CurrentShowPageIndex);
   }
 
  });
 }
 /// 

 /// 设置信息
 /// 
 /// 总页数
 /// 显示多少个按钮，填奇数，如果填偶数，则会强制减1，如：填6，则实际为5
 /// 上一页按钮事件
 /// 下一页按钮事件
 /// 单独点击页面按钮事件
 public void Set(int totalPageNumber,int showBtnCount,UnityAction lastBtnEvent,UnityAction nextBtnEvent,UnityAction pageBtnClickEvent) {
  if (totalPageNumber <= 0)
  {
   this.totalPageNumber = 1;
  }
  else {
   this.totalPageNumber = totalPageNumber;
  }
  
  this.ShowBtnCount = showBtnCount;
 
  this.lastPageBtnEvent = lastBtnEvent;
  this.nextPageBtnEvent = nextBtnEvent;
 
  CurrentShowPageIndex = 1;
 
  pbcList.Clear();
 
  for (int i = 1; i <= ShowBtnCount; i++) {
   int index = i;
   PageBtnC pbc = PoolManager.Instance.Spawn(btnPrefabs, pageBtnParent).GetComponent();
   if (pbc) {
    pbc.Set(index,null, (pageIndex,pbc111) =>
    {
     CurrentShowPageIndex = pageIndex;
 
     ResetPageBtnState();
 
     ChangeShowState();
 
     PageBtnC pbc1 = GetPBCFromIndex(CurrentShowPageIndex);
     if (pbc1 != null)
     {
      pbc1.SetHighlightColor();
     }
     if (pageBtnClickEvent != null) {
      pageBtnClickEvent(pageIndex, pbc111);
     }
    });
   }
   pbcList.Add(pbc);
  }
 
  pbcList[0].SetHighlightColor();
 
  ChangeShowState();
 
  Util.SetWidth_ChildWidthSame(pageBtnParent_HLG, pageBtnParent);
 
  Util.SetWidth_ChildWidthNotSame(self_HLG, transform as RectTransform);
 }
 /// 

 /// 重置所有按钮的状态
 /// 
 void ResetPageBtnState() {
  for (int i = 0; i < pbcList.Count; i++) {
   pbcList[i].SetNormalColor();
  }
 }
 /// 

 /// 回收所有页码
 /// 
 public void Unspawn() {
  for (int i = pageBtnParent.childCount - 1; i >= 0; i--) {
   
   PoolManager.Instance.UnSpawn(pageBtnParent.GetChild(i).gameObject);
  }
 }
 
 public void Clear() {
  lastPageBtnEvent = null;
  nextPageBtnEvent = null;
 }
 /// 

 /// 根据index得到pagebtnc物体
 /// 
 /// 
 /// 
 PageBtnC GetPBCFromIndex(int index) {
  for (int i = 0; i < pbcList.Count; i++) {
   if (pbcList[i].CurrentPageIndex.Equals(index)) {
    return pbcList[i];
   }
  }
 
  return null;
 }
}
 
public class Util
{
 /// 

 /// 设置物体宽度 子物体宽度相同
 /// 
 /// 
 /// 
 /// 
 public static void SetWidth_ChildWidthSame(HorizontalLayoutGroup parentHLG, RectTransform parent, UnityAction endCallBack = null)
 {
  float width = 0;
 
  float leftPadding = parentHLG.padding.left;
  float spacing = parentHLG.spacing;
 
  int childCount = parent.childCount;
 
  if (childCount > 0)
  {
   RectTransform singleChildRT = parent.GetChild(0) as RectTransform;
 
   width = childCount * singleChildRT.rect.width + (childCount - 1) * spacing + leftPadding;
  }
 
  parent.sizeDelta = new Vector2(width, parent.sizeDelta.y);
 
  if (endCallBack != null)
  {
   endCallBack(width);
  }
 }
 
 /// 

 /// 设置物体宽度 子物体宽度不同
 /// 
 /// 
 /// 
 /// 
 public static void SetWidth_ChildWidthNotSame(HorizontalLayoutGroup parentHLG, RectTransform parent, UnityAction endCallBack = null)
 {
  float width = 0;
 
  RectOffset Padding = parentHLG.padding;
  float spacing = parentHLG.spacing;
 
  int childCount = parent.childCount;
 
  if (childCount > 0)
  {
   for (int i = 0; i < childCount; i++)
   {
    RectTransform childRT = parent.GetChild(i) as RectTransform;
    width += childRT.rect.width;
   }
 
   width += (childCount - 1) * spacing + Padding.left + Padding.right;
  }
 
  parent.sizeDelta = new Vector2(width, parent.sizeDelta.y);
 
  if (endCallBack != null)
  {
   endCallBack(width);
  }
 }
}

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Events;
using UnityEngine.UI;
/// 

/// 页码按钮控制器
/// 
public class PageBtnC : MonoBehaviour,IPool {
 /// 

 /// 自己显示的页码
 /// 
 private int currentPageIndex = 0;
 public int CurrentPageIndex {
  get {
   return currentPageIndex;
  }
 }
 
 private Button SelfBtn;
 private Image img;
 private Text selfText;
 
 /// 

 /// 按钮事件
 /// 
 public UnityAction btnClickEvent;
 
 /// 

 /// 按钮正常和高亮颜色
 /// 
 public Color normalColor;
 public Color highlightColor;
 
 /// 

 /// 文本正常和高亮颜色
 /// 
 public Color normalTextColor;
 public Color highlightTextColor;
 
 private bool isInit = false;
 void Init() {
  if (isInit)
   return;
  isInit = true;
 
  img = transform.GetComponent();
 
  selfText = transform.Find("Text").GetComponent();
 
  SelfBtn = transform.GetComponent();
  SelfBtn.onClick.AddListener(()=> {
   
   if (btnClickEvent != null) {
    btnClickEvent(currentPageIndex,this);
   }
  });
 }
 /// 

 /// 设置正常颜色
 /// 
 public void SetNormalColor() {
  img.color = normalColor;
  selfText.color = normalTextColor;
 }
 /// 

 /// 设置高亮颜色
 /// 
 public void SetHighlightColor() {
  img.color = highlightColor;
  selfText.color = highlightTextColor;
 }
 /// 

 /// 设置事件 文本内容等
 /// 
 /// 
 /// 
 /// 
 public void Set(int currentPageIndex,string selfTextStr = null,UnityAction btnClickEvent = null) {
  this.currentPageIndex = currentPageIndex;
 
  if (btnClickEvent != null)
  {
   this.btnClickEvent = btnClickEvent;
  }
 
  if (string.IsNullOrEmpty(selfTextStr))
  {
   selfText.text = currentPageIndex.ToString();
  }
  else {
   selfText.text = selfTextStr;
  }
 }
 
 #region 对象池接口方法
 public int GetMaxCount()
 {
  return 10;
 }
 
 public string SingletonName()
 {
  return this.GetType().Name;
 }
 
 public void Spawn()
 {
  Init();
 }
 
 public void UnSpawn()
 {
  SetNormalColor();
 }
 #endregion
}