unity双层滑动实现

实现功能：
当滑动列表中内容处于顶端的时候，向上滑动优先滑动整个滑动列表，当滑动列表移动到设置位置，即设定的最高处时，继续移动列表内内容。向下移动亦然，当内容处于滑动列表顶端时，移动整个滑动列表。

eventtriggerlistener脚本可在这篇查看unity防止ui点击事件被子物体拦截

using UnityEngine;
using UnityEngine.UI;
using DG.Tweening;public class ScrollViewMove : MonoBehaviour
{public ScrollRect m_scorllView;public RectTransform m_rectView;private void Start(){//添加滑动事件Graphic horizontalGraphic = m_scorllView.GetComponent<Graphic>();if (horizontalGraphic != null && horizontalGraphic.raycastTarget){EventTriggerListener.Get(m_scorllView.gameObject).onBeginDrag = OnScrollBeginDrag;EventTriggerListener.Get(m_scorllView.gameObject).onDrag = OnScrollDrag;EventTriggerListener.Get(m_scorllView.gameObject).onEndDrag = OnScrollEndDrag;}//设置最高高度，和出现滑动时的阈值m_minHeight = m_scorllView.GetComponent<RectTransform>().localPosition.y;m_LimitY = (m_maxHeight - m_minHeight) * MOVE_DISTANCE_SCALE;}#region 滑动条事件//起始滑动位置private float m_startScrollHeight = 0f;//结束滑动位置private float m_endScrollHeight = 0f;//限制切换动画的最小判断private float m_LimitY;private readonly float MOVE_DISTANCE_SCALE = 0.2f;//起始鼠标位置private float m_startMouseHeight = 0f;//中途鼠标位置private float m_partMouseHeight = 0f;//最大高度private float m_maxHeight = 0f;//最小高度private float m_minHeight = 0f;//是否为展开状态private bool m_isOpen = false;/// <summary>/// 滑动列表开始拖拽事件/// </summary>/// <param name="obj"></param>private void OnScrollBeginDrag(GameObject obj){m_startScrollHeight = m_scorllView.GetComponent<RectTransform>().localPosition.y;m_startMouseHeight = Input.mousePosition.y;}/// <summary>/// 滑动列表拖拽事件/// 先判断走拖拽事件还是滑动列表滑动事件/// </summary>/// <param name="obj"></param>private void OnScrollDrag(GameObject obj){m_partMouseHeight = Input.mousePosition.y;float m_offsetHeight = m_partMouseHeight - m_startMouseHeight;m_startMouseHeight = m_partMouseHeight;float scrollPosY = m_scorllView.GetComponent<RectTransform>().localPosition.y;if (scrollPosY >= m_maxHeight){if (m_offsetHeight >= 0){m_scorllView.vertical = true;return;}else{if (m_scorllView.verticalNormalizedPosition < 1){m_scorllView.vertical = true;return;}}}else if (scrollPosY <= m_minHeight){if (m_offsetHeight <= 0){m_scorllView.vertical = true;return;}else{if (m_scorllView.verticalNormalizedPosition > 1){m_scorllView.vertical = true;return;}}}m_scorllView.verticalNormalizedPosition = 1;m_scorllView.vertical = false;OnPosDrag(m_offsetHeight);}/// <summary>/// 设置滑动位置/// </summary>/// <param name="offset"></param>private void OnPosDrag(float offset){//设置滑动列表位置Vector3 scrollPos = m_scorllView.GetComponent<RectTransform>().localPosition;float endPosY = scrollPos.y + offset;if (endPosY > m_maxHeight){offset = m_maxHeight - scrollPos.y;}else if (endPosY < m_minHeight){offset = m_minHeight - scrollPos.y;}scrollPos = new Vector3(scrollPos.x, scrollPos.y + offset, scrollPos.z);m_scorllView.GetComponent<RectTransform>().localPosition = scrollPos;//设置滑动列表遮罩大小Vector2 viewPos = m_rectView.offsetMin;viewPos = new Vector2(viewPos.x, viewPos.y - offset);m_rectView.offsetMin = viewPos;}/// <summary>/// 滑动列表结束拖拽事件/// </summary>/// <param name="obj"></param>private void OnScrollEndDrag(GameObject obj){m_endScrollHeight = m_scorllView.GetComponent<RectTransform>().localPosition.y;float offset = m_endScrollHeight - m_startScrollHeight;if (Mathf.Abs(offset) >= m_LimitY){m_isOpen = (offset > 0);}ScrollDragAni(m_isOpen);}//动画播放时间private readonly float TWEEN_POS_TIME = 0.2f;/// <summary>/// 滑动条动画/// </summary>/// <param name="isOpen"></param>private void ScrollDragAni(bool isOpen){Vector3 scrollPos = m_scorllView.GetComponent<RectTransform>().localPosition;if (isOpen){DOTween.To(() => scrollPos.y,(v) =>{Vector3 tmpVec = m_scorllView.GetComponent<RectTransform>().localPosition;float offset = v - tmpVec.y;OnPosDrag(offset);}, m_maxHeight, TWEEN_POS_TIME).OnComplete(() => { m_isOpen = true; });}else{DOTween.To(() => scrollPos.y,(v) =>{Vector3 tmpVec = m_scorllView.GetComponent<RectTransform>().localPosition;float offset = v - tmpVec.y;OnPosDrag(offset);},  m_minHeight, TWEEN_POS_TIME).OnComplete(() => { m_isOpen = false; });}}#endregion
}

设置，在滑动列表中，将ViewPort设置成顶端锚点