UGUI ScrollRect滑动定位优化详解

using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;
using System;

public class ScrollRectMe : ScrollRect
{
 [SerializeField]
 public float inertiaMaxTime = 0.5f;//限制惯性持续时间

 public Action<GameObject > stopScrollCallback = null;//滑动结束的回调

 private float _scrolledTime = 0f;
 private Action<GameObject> _stopScrollCallback = null;

 private Vector2 _lastPostion = Vector2.zero;

 public override void OnEndDrag(PointerEventData eventData)
 {
 base.OnEndDrag(eventData);
 _stopScrollCallback = stopScrollCallback;
 _scrolledTime = 0f;
 _lastPostion = Vector2.zero;
 }

 public override void OnDrag(PointerEventData eventData)
 {
 base.OnDrag(eventData);
 _scrolledTime = 0f;
 _lastPostion = Vector2.zero;
 }

 public override void StopMovement()
 {
 base.StopMovement(); 
 }

 protected override void LateUpdate()
 {
 // base.LateUpdate();
 }

 private void Update()
 {
 base.LateUpdate();
 }

 protected override void SetContentAnchoredPosition(Vector2 position)
 {
 //2017-6-27 修改补充条件
 if (_scrolledTime >= inertiaMaxTime || (position.ToString("0.0") == _lastPostion.ToString("0.0")))
 {
 if (_stopScrollCallback != null)
 {
 _stopScrollCallback(transform.gameObject);
 _stopScrollCallback = null;
 }
 _scrolledTime = inertiaMaxTime;
 return;
 }

 base.SetContentAnchoredPosition(position);

 _scrolledTime += Time.unscaledDeltaTime;
 _lastPostion = position;
 } 
}