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）

---

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 _toggleList = new List();        
         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().value = true;
                }                  
            }               
            _currentPage = 1;
            _isStart = true;
        }        
    }
    /// 

    /// 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）
    /// 
    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().spriteName = secondSpriteItem.GetComponent().spriteName = ItemData.SpriteName[i];
        }
    }

    /// 

    /// 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）
    /// 
    /// 
    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().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
{  
    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();
            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();                  
            }
            else
            {
                scroll = tf.gameObject.GetComponent();
            }
            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;
    }
}
}