Unity3d学习笔记-无限循环滚动背景（完整的商店广告牌组件）

在游戏项目中我们常常看到商城的广告牌，几张广告图片循环滚动，类似跑马灯，现在我将讨论一种实现方法，并提供一个管理类，大家可以直接使用。

实现原理：背景图片循环滚动的原理很简单：两张图片向一个方向移动，当达某张图片到临界区域时将图片放在后面，依次循环。

在实际项目中，广告牌显示的图片数量不确定，例如某个假期活动会上很多新品，此时我们需要动态的创建显示的图片（一般在配置表读取数据），如果需要显示分类标签还得动态生成分类标签。

综上所述，一个完整的广告牌组件应该具有以下功能：
- 无限循环的滚动背景图片
- 根据读取的数据动态生成图片
- 具有分类标签，根据显示图片动态生成
- *做成一个管理类，方便使用（一个项目中可能多处会用到）

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下面谈谈我的方法：
第一步：创建滚动组件AdvertisementScroll，这个组件挂在GameObject上面，接受传递过来的数据，生成显示的图片和分类标签，在Update中实现无限循环滚动。

using System.Collections.Generic;using UnityEngine;namespace Assets.Scripts.Client{     public class AdvertisementScroll : MonoBehaviour    {            private float _timer;         private bool _isStart;         private Vector3 _toggleCenter;         private int delDistance;         private int _currentPage; //当前页面             private AdvertisementScrollManager.AdvertisementScrollData _itemData;                private List<ToggleData> _toggleList = new List<ToggleData>();                 private Vector3 _toLeftPosition;//向左滑动到某个位置         public class ToggleData         {            public string name;            public GameObject go;         }        public AdvertisementScrollManager.AdvertisementScrollData ItemData        {            get { return _itemData; }            set { _itemData = value; }        }    public void StartScroll(bool createToggle)    {        if (!_isStart)        {            CreateAdvertiseBg();            CreateAdvertiseToggle(createToggle);            if (createToggle)            {                if (ItemData.ToggleItem != null)                {                    ItemData.ToggleItem.GetComponent<UIToggle>().value = true;                }                              }                           _currentPage = 1;            _isStart = true;        }            }    /// <summary>    /// 创建需要显示的图片（需要图片数量，图片精灵名称，图片的宽度，图片左边和右边的显示位置）    /// </summary>    private void CreateAdvertiseBg()    {        _toLeftPosition = new Vector3(ItemData.LeftPosition.x - ItemData.SpriteWidth, ItemData.LeftPosition.y, ItemData.LeftPosition.z);        for (int i = 0; i < ItemData.MaxPage; i++)        {            GameObject firstSpriteItem;            GameObject secondSpriteItem;            if (i == 0)            {                firstSpriteItem = secondSpriteItem = ItemData.SpriteItem.gameObject;            }            else            {                firstSpriteItem = ItemData.FirstMoveGo.gameObject.AddChild(ItemData.SpriteItem.gameObject);                firstSpriteItem.SetActive(false);                secondSpriteItem = ItemData.SecondMoveGo.gameObject.AddChild(ItemData.SpriteItem.gameObject);                secondSpriteItem.SetActive(false);            }            firstSpriteItem.transform.localPosition = secondSpriteItem.transform.localPosition = Vector3.zero;            firstSpriteItem.name = secondSpriteItem.name = (i + 1).ToString();            firstSpriteItem.GetComponent<UISprite>().spriteName = secondSpriteItem.GetComponent<UISprite>().spriteName = ItemData.SpriteName[i];        }    }    /// <summary>    /// 创建分页图片,默认不创建（需要分页图片，分页的中间位置，每个分页的间隔）    /// </summary>    /// <param name="create"></param>    private void CreateAdvertiseToggle(bool create = false)    {        if (create)        {            _toggleCenter = ItemData.ToggleCenterPos;            delDistance = ItemData.ToggleDistance;                   Vector3 firstpoint = _toggleCenter - new Vector3((ItemData.MaxPage / 2f - 0.5f) * delDistance, 0f, 0f);            for (int i = 0; i < ItemData.MaxPage; i++)            {                GameObject item;                ToggleData toggleData = new ToggleData();                if (i == 0)                {                    item = ItemData.ToggleItem.gameObject;                }                else                {                    item = ItemData.ToggleContainer.gameObject.AddChild(ItemData.ToggleItem.gameObject);                }                item.transform.localPosition = firstpoint + new Vector3(i*delDistance, 0f, 0f);                item.name = "toggle" + i;                toggleData.go = item;                toggleData.name = item.name;                _toggleList.Add(toggleData);            }        }    }    void Update()    {        if (!_isStart)        {            return;                      }        if (Time.frameCount % (30 * ItemData.MoveTime) == 0 && ItemData.MaxPage > 1)        {            if (ItemData.FirstMoveGo.localPosition.x < ItemData.LeftPosition.x - 0.5)            {                ItemData.FirstMoveGo.localPosition = ItemData.RightPosition;            }            if (ItemData.SecondMoveGo.localPosition.x < ItemData.LeftPosition.x - 0.5)            {                ItemData.SecondMoveGo.localPosition = ItemData.RightPosition;            }            Transform leftTran = ItemData.FirstMoveGo.localPosition.x < ItemData.SecondMoveGo.localPosition.x ? ItemData.FirstMoveGo : ItemData.SecondMoveGo;            Transform rightTran = ItemData.FirstMoveGo.localPosition.x < ItemData.SecondMoveGo.localPosition.x ? ItemData.SecondMoveGo : ItemData.FirstMoveGo;            TweenPosition.Begin(rightTran.gameObject, 0.5f, ItemData.LeftPosition, false);            TweenPosition.Begin(leftTran.gameObject, 0.5f, _toLeftPosition, false);            _currentPage = FixPage(_currentPage);            SetPic(rightTran, _currentPage);            //SetBtn(leftTran,false);            //SetBtn(rightTran,true);                           _toggleList[_currentPage - 1].go.GetComponent<UIToggle>().value = true;        }    }    private void SetBtn(Transform tran, bool state)    {        Transform tf = tran.Find("Icon");        if (tf != null)        {            tf.gameObject.SetActive(state);        }               }    private void SetPic(Transform tran, int _currentPage)    {        foreach (Transform t in tran)        {            if (t.name == _currentPage.ToString())            {                t.gameObject.SetActive(true);            }            else            {                t.gameObject.SetActive(false);            }        }    }    private int FixPage(int page)    {        page++;        if (page > ItemData.MaxPage)        {            page = 1;        }        return page;    }}    }

第二步：创建管理类AdvertisementScrollManager，将它做成一个单例，调用AdvertisementScroll的方法，开始滚动。

using UnityEngine;using System.Collections.Generic;namespace Assets.Scripts.Client{public class AdvertisementScrollManager : Singleton<AdvertisementScrollManager>{      public struct AdvertisementScrollData    {        public bool IsCreateToggle;       //是否创建分页标签        public Transform ToggleItem;      //分页标签        public Transform ToggleContainer; //分页标签所在的Panel        public Vector3 ToggleCenterPos;   //分页标签的中间位置        public int ToggleDistance;        //分页标签之间的间隔        public Transform FirstMoveGo;     //移动的物体        public Transform SecondMoveGo;    //移动的物体        public Vector3 LeftPosition;      //移动物体的左边位置        public Vector3 RightPosition;     //移动物体的右边位置        public Transform SpriteItem;      //显示的图片        public int SpriteWidth;           //图片的宽度        public string[] SpriteName;       //显示的所有图片在图集中的名称        public int MaxPage;               //最大的页面        public int MoveTime;              //每隔多少秒移动一次    };    public void StartAdvertisementScroll(Transform parentTf, AdvertisementScrollData data,bool createToggle = false)    {        if (parentTf != null)        {            UIPanel panel = parentTf.GetComponent<UIPanel>();            if (panel == null)            {                return;            }            AdvertisementScroll scroll = null;            Transform tf = parentTf.Find("AdvertisementScroll");            if (tf == null)            {                GameObject go = new GameObject();                go.name = "AdvertisementScroll";                go.transform.parent = parentTf;                go.transform.localPosition = Vector3.zero;                go.transform.localScale = new Vector3(1, 1, 1);                //go.layer = LayerModel.UILayer;                tf = go.transform;                scroll = tf.gameObject.AddComponent<AdvertisementScroll>();                              }            else            {                scroll = tf.gameObject.GetComponent<AdvertisementScroll>();            }            scroll.ItemData = data;            scroll.ItemData.FirstMoveGo.parent = tf;            scroll.ItemData.SecondMoveGo.parent = tf;            scroll.StartScroll(createToggle);        }    }}}

第三步：使用。预制体的制作方法就不说了，代码看懂了自然好弄，后面也会附上工程文件。你在任何一个界面需要使用广告牌组件时只需要先设置好数据，然后调用AdvertisementScrollManager中的StartAdvertisementScroll方法就可以了。

using Assets.Scripts.Client;using UnityEngine;namespace Assets{public class AdvertiseScrollSample : MonoBehaviour{    private Transform _firstMoveGo;    private Transform _secondMoveGo;    private Transform _container;    private Transform _toggleContainer;    private Transform _spriteItem;    private Transform _toggleItem;          void Start ()    {        _firstMoveGo = transform.Find("Panel/Container/First");        _secondMoveGo = transform.Find("Panel/Container/Second");        _container = transform.Find("Panel/Container");        _toggleContainer = transform.Find("Panel/ToggleContainer");        _spriteItem = transform.Find("Panel/Container/First/Item");        _toggleItem = transform.Find("Panel/ToggleContainer/ToggleItem");        OnRefreshData();    }    void OnRefreshData()    {        AdvertisementScrollManager.AdvertisementScrollData data = CreateAdvertisementScrollData();        AdvertisementScrollManager.Instance.StartAdvertisementScroll(_container,data,data.ToggleContainer);    }    private AdvertisementScrollManager.AdvertisementScrollData CreateAdvertisementScrollData()    {        AdvertisementScrollManager.AdvertisementScrollData data = new AdvertisementScrollManager.AdvertisementScrollData();        //设置显示图片的数量和滑动的时间间隔        data.MoveTime = 10;        data.MaxPage = 3;        //设置图片的位置信息        data.FirstMoveGo = _firstMoveGo;        data.SecondMoveGo = _secondMoveGo;        data.SpriteItem = _spriteItem;        data.SpriteWidth = 884;        data.SpriteName = new string[] { "1", "2", "3" };        data.LeftPosition = Vector3.zero;        data.RightPosition = new Vector3(800, 0, 0);        //设置分页标签信息（如果不需要分页标签，可以不用赋值）        data.IsCreateToggle = true;        data.ToggleItem = _toggleItem;        data.ToggleContainer = _toggleContainer;          data.ToggleCenterPos = new Vector3(0,-200,0);        data.ToggleDistance = 30;                                      return data;    }}}