Unity状态模式实战：解决GameObject行为扩展难题
下面是一个关于方块的简单实现，关于方块 以及地图方块的相关内容，主要是鼠标移动到方块，以及单击方块的内容。
方块的生成涉及对象池，但在本文可以不需要过多理解。
using System.Collections; using System.Collections.Generic; using UnityEngine; public abstract class Square : MonoBehaviour { public SquareTypeList Type; public enum SquareTypeList { MapSquare=0, } public abstract void Initialize(Vector2 position, SquareTypeList squareType); public abstract void Activate(); public abstract void Deactivate(); } using System.Collections; using System.Collections.Generic; using UnityEngine; public class MapSquare : Square { private SpriteRenderer _spriteRenderer; private void Awake() { _spriteRenderer = GetComponent<SpriteRenderer>(); } public override void Activate() { gameObject.SetActive(true); } public override void Deactivate() { gameObject.SetActive(false); } public override void Initialize(Vector2 squarePosiont, SquareTypeList squareType) { transform.position = squarePosiont; Type = squareType; Activate(); return; } private void Update() { } private void OnMouseEnter() { _spriteRenderer.color = Color.red; } private void OnMouseExit() { _spriteRenderer.color = Color.white; } private void OnMouseDown() { EventCenter.Instance.TriggerEvent<GameObject>( GameEvent.ReturnSquareToPoolEvent, this, this.gameObject); } }上面是我问题的源代码部分
这个代码在继承上存在设计问题，假如我要扩展更多类型的方块，并且方块类型改变，自然的切换到另一种。
一般的思路可能是要么
1写更多的方块脚本如map2square之类的，让方块实体卸载当前脚本再挂上它。
2还是设计一种状态，根据其基本的类型值进行变换成其他方块，但都写在一个类（脚本）里,
3创建不同的预制体，设置更多的不同种类砖块的对象池来进行。
问题分别是，1卸载脚本在砖块很多的当下似乎并不划算。2一个类里代码太多，比如5种砖块的5种消失执行都写在同一个脚本里，设计上看起来就很奇怪。3可行 但思路上还是跟状态模式不一样。
你也许发现了代码中SquareTypeList根本没用上，
如果参照状态模式进行的话
状态模式管Square叫做上下文
图里面的两个方块 就是状态切换机制 通过接口来实现对不同状态下的方法的调用，算是一种简单的分离法。
具体代码如下，同样只包含核心内容。
using System.Collections; using System.Collections.Generic; using UnityEngine; public class Square : MonoBehaviour { [HideInInspector] public SquareType currentType; private ISquareState _currentState; private SpriteRenderer _spriteRenderer; private static readonly Dictionary<SquareType, ISquareState> _stateMap = new() { {SquareType.MapSquare,new MapSquareState() }, }; private void Awake() { _spriteRenderer = GetComponent<SpriteRenderer>(); } public void Initialize(Vector2 position, SquareType squareType) { currentType = squareType; // 切换到对应状态并初始化 _currentState = _stateMap[squareType]; _currentState.Initialize(this, position); Activate(); } public void Activate() => _currentState?.Activate(); public void Deactivate() => _currentState?.Deactivate(); private void OnMouseEnter() => _currentState?.OnMouseEnter(); private void OnMouseExit() => _currentState?.OnMouseExit(); private void OnMouseDown() => _currentState?.OnMouseDown(); public SpriteRenderer GetSpriteRenderer() => _spriteRenderer; }接口代码
using UnityEngine; public interface ISquareState { void Initialize(Square square, Vector2 position); void Activate(); void Deactivate(); void OnMouseEnter(); void OnMouseExit(); void OnMouseDown(); }一个实现
using UnityEngine; public class MapSquareState : ISquareState { private Square _square; private SpriteRenderer _spriteRenderer; public void Initialize(Square square, Vector2 position) { _square = square; _spriteRenderer = _square.GetComponent<SpriteRenderer>(); _square.transform.position = position; } public void Activate() { _square.gameObject.SetActive(true); } public void Deactivate() { _square.gameObject.SetActive(false); } public void OnMouseEnter() { _spriteRenderer.color = Color.red; } public void OnMouseExit() { _spriteRenderer.color = Color.white;} public void OnMouseDown() { EventCenter.Instance.TriggerEvent<GameObject>( GameEvent.ReturnSquareToPoolEvent, _square, _square.gameObject); } }可以发现，在MapSquareState是有Square类的 _square引用的，该设计模式存在耦合 但耦合并非绝对的错误。在这里可以方便的扩展更多的类别，只要在一个枚举类里增加如下
public enum SquareType { // 基础地图方块 MapSquare = 0, BlockedSquare =1, // 封禁层 - 需要特殊条件触发，不可点击 }然后是状态类
using UnityEngine public class BlockedSquareState : ISquareState { public void Activate() { throw new System.NotImplementedException(); } public void Deactivate() { throw new System.NotImplementedException(); } public void Initialize(Square square, Vector2 position) { throw new System.NotImplementedException(); } public void OnMouseDown() { Debug.Log("封禁层 不可点"); return; } public void OnMouseEnter() { throw new System.NotImplementedException(); } public void OnMouseExit() { throw new System.NotImplementedException(); } }以及在square类中添加一个新的状态
private static readonly Dictionary<SquareType, ISquareState> _stateMap = new() { {SquareType.MapSquare,new MapSquareState() }, {SquareType.BlockedSquare,new BlockedSquareState() }, //新增 };后回到页面里添加一些方块实例的预制体就好了（这是指我的对象池子，对象池也有更改）。展现部分关键代码。
public class MapSquareManager : MonoBehaviour { [System.Serializable] public class SquarePoolConfig { public SquareType squareType; // 方块类型 public Square squarePrefab; // 对应预制体（挂载Square组件） public int maxCount = 30; // 该类型池最大数量 } [Header("多类型方块池配置")] [SerializeField] private List<SquarePoolConfig> poolConfigs; // 多类型配置列表 private Dictionary<SquareType, Queue<GameObject>> _squarePools; private void Awake() { _squarePools = new Dictionary<SquareType, Queue<GameObject>>(); InitializePool(); } private void Start() { GenerateMap(); } public void InitializePool() { //for (int i = 0; i < mapSquareMaxCount; i++) //{ // GameObject mapSquare = Instantiate(mapSquarePre); // mapSquare.SetActive(false); // mapSquarePool.Enqueue(mapSquare); //} foreach (var config in poolConfigs) { Queue<GameObject> pool = new Queue<GameObject>(); for (int i = 0; i < config.maxCount; i++) { Square square = Instantiate(config.squarePrefab); square.gameObject.SetActive(false); square.gameObject.transform.SetParent(transform);//这样的话square 是mapsquarestate 还是 square pool.Enqueue(square.gameObject); } _squarePools.Add(config.squareType, pool); } } }以上 完毕！
