使用ScrollRect制作翻页

1.标准的层级结构 ScrollRect->ViewPort->Content，Viewport负责显示区域的大小一般和Mask一起配合使用，Content使用Layout来布局，如果想使用代码来自动定位显示位置需要在Content加上Content size filter.

2.ScrollRectHelper

using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;
using System.Collections.Generic;
using System;

public class ScrollRectHelper : MonoBehaviour, IBeginDragHandler, IEndDragHandler
{
    // 滑动速度
    public float smooting = 5;

    // 每页显示的项目
    [SerializeField]
    private int countPerPage = 10;

    ScrollRect srect;
    // 总页数
    float totalPages;
    // 是否拖拽结束
    bool isDrag = false;
    // 总页数索引比列 0-1
    List<float> listPageValue = new List<float> { 0 };
    // 滑动的目标位置
    public float targetPos = 0;
    // 当前位置索引
    float nowindex = 0;                                 

    void Awake()
    {
        srect = GetComponent<ScrollRect>();
    }

    public string PageText()
    {
        return (nowindex + 1) + "/" + (totalPages + 1);
    }

    // 计算每页比例
    public void CalcListPageValue<T>() where T : MonoBehaviour
    {
        T[] items = srect.content.GetComponentsInChildren<T>();
        srect.content.rect.Set(srect.content.rect.width / 2, srect.content.rect.y, srect.content.rect.width, srect.content.rect.height);
        totalPages = (int)(Math.Ceiling((float)items.Length / countPerPage) - 1);
        if (items.Length != 0)
        {
            for (float i = 1; i <= totalPages; i++)
            {
                //Debug.Log(i / totalPages);
                listPageValue.Add((i / totalPages));
            }
        }
    }

    void Update()
    {
        if (!isDrag)
        {
            srect.horizontalNormalizedPosition = Mathf.Lerp(srect.horizontalNormalizedPosition, targetPos,
                Time.deltaTime * smooting);
        }

        // Debug
        if (Input.GetKeyDown(KeyCode.LeftArrow)) PressLeft();
        if (Input.GetKeyDown(KeyCode.RightArrow)) PressRight();
    }

    /// <summary>
    /// 拖动开始
    /// </summary>
    /// <param name="eventData"></param>
    public void OnBeginDrag(PointerEventData eventData)
    {
        isDrag = true;
    }

    /// <summary>
    /// 拖拽结束
    /// </summary>
    /// <param name="eventData"></param>
    public void OnEndDrag(PointerEventData eventData)
    {
        isDrag = false;
        var tempPos = srect.horizontalNormalizedPosition; //获取拖动的值
        var index = 0;
        float offset = Mathf.Abs(listPageValue[index] - tempPos);    //拖动的绝对值
        for (int i = 1; i < listPageValue.Count; i++)
        {
            float temp = Mathf.Abs(tempPos - listPageValue[i]);
            if (temp < offset)
            {
                index = i;
                offset = temp;
            }
        }
        targetPos = listPageValue[index];
        nowindex = index;
    }

    public void PressLeft()
    {
        nowindex = Mathf.Clamp(nowindex - 1, 0, totalPages);
        targetPos = listPageValue[Convert.ToInt32(nowindex)];
    }

    public void PressRight()
    {
        nowindex = Mathf.Clamp(nowindex + 1, 0, totalPages);
        targetPos = listPageValue[Convert.ToInt32(nowindex)];
    }
}