参考连接：https://blog.csdn.net/weixin_41814169/article/details/88890650

今天做一个滑动翻页效果，便用上面连接的轮子做滑动翻页效果，但是这个滑动翻页效果只支持滑动，不支持设置index之后滑动过去，故做了修改以支持idnex滑动翻页效果~
顺便记录一下~

注意：

SetIndexMove(int index) 这个方法便是设置index滑动

using UnityEngine;
using System.Collections;
using UnityEngine.UI;
using System.Collections.Generic;
using UnityEngine.EventSystems;
using System;
    public class PageView : MonoBehaviour, IBeginDragHandler, IEndDragHandler
    {
        ScrollRect rect;                        //滑动组件  
                                                //public ScrollRect rect2;                        //滑动组件2  

        private float targethorizontal = 0;             //滑动的起始坐标  
        private bool isDrag = false;                    //是否拖拽结束  
        private List<float> posList = new List<float>();//求出每页的临界角，页索引从0开始  
        private int currentPageIndex = -1;
        public Action<int> OnPageChanged;

        private bool stopMove = true;
        public float smooting = 4;      //滑动速度  
        public float sensitivity = 0;
        private float startTime;

        private float startDragHorizontal;

        bool isInit = false;
        public void Init()
        {
            // rect = rect2;
            rect = transform.GetComponent<ScrollRect>();
            // rect2 = transform.GetComponent<ScrollRect>();
            float horizontalLength = rect.content.rect.width - GetComponent<RectTransform>().rect.width;
            //float horizontalLength2 = rect2.content.rect.width - GetComponent<RectTransform>().rect.width;
            posList.Add(0);
            for (int i = 1; i < rect.content.transform.childCount - 1; i++)
            {
                posList.Add(GetComponent<RectTransform>().rect.width * i / horizontalLength);
            }
            posList.Add(1);
            isInit = true;
        }

        void Update()
        {
            if (isInit)
            {
                if (!isDrag && !stopMove)
                {
                    startTime += Time.deltaTime;
                    float t = startTime * smooting;
                    rect.horizontalNormalizedPosition = Mathf.Lerp(rect.horizontalNormalizedPosition, targethorizontal, t);
                    // rect2.horizontalNormalizedPosition = Mathf.Lerp(rect2.horizontalNormalizedPosition, targethorizontal, t);
                    if (t >= 1)
                        stopMove = true;
                }
            }
        }

        public void pageTo(int index)
        {
            if (!isInit) return;
            if (index >= 0 && index < posList.Count)
            {
                rect.horizontalNormalizedPosition = posList[index];
                SetPageIndex(index);
            }
            else
            {
                Debug.LogWarning("页码不存在");
            }
        }
        private void SetPageIndex(int index)
        {
            if (!isInit) return;
            if (currentPageIndex != index)
            {
                currentPageIndex = index;
                if (OnPageChanged != null)
                    OnPageChanged(index);
            }
        }

        public void OnBeginDrag(PointerEventData eventData)
        {
            if (!isInit) return;
            isDrag = true;
            startDragHorizontal = rect.horizontalNormalizedPosition;
            // startDragHorizontal = rect2.horizontalNormalizedPosition;
        }

        public void OnEndDrag(PointerEventData eventData)
        {
            if (!isInit) return;
            float posX = rect.horizontalNormalizedPosition;
            posX += ((posX - startDragHorizontal) * sensitivity);
            posX = posX < 1 ? posX : 1;
            posX = posX > 0 ? posX : 0;
            int index = 0;
            float offset = Mathf.Abs(posList[index] - posX);
            for (int i = 1; i < posList.Count; i++)
            {
                float temp = Mathf.Abs(posList[i] - posX);
                if (temp < offset)
                {
                    index = i;
                    offset = temp;
                }
            }
            SetPageIndex(index);

            targethorizontal = posList[index]; //设置当前坐标，更新函数进行插值  
            isDrag = false;
            startTime = 0;
            stopMove = false;
        }

        public void SetIndexMove(int index)
        {
            if (index < 0)
            {
                index = index < 0 ? posList.Count - 1 : index;
            }
            else if (index >= posList.Count)
            {
                index = index >= posList.Count ? 0 : index;
            }

            SetPageIndex(index);
            targethorizontal = posList[index]; //设置当前坐标，更新函数进行插值

            startTime = 0;
            stopMove = false;
        }
    }