🕊️ 中介者模式（Mediator Pattern）深度解析

——以Unity实现跨系统通信与复杂UI协调为核心案例

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一、模式本质与核心价值

核心目标：
✅ 解耦对象间的直接依赖，通过中介者集中管理交互
✅ 简化网状通信为星型结构，提升系统可维护性
✅ 统一控制交互逻辑，便于扩展新通信规则

关键术语：

• Mediator（中介者接口）：定义对象间通信的接口
• ConcreteMediator（具体中介者）：实现协调逻辑
• Colleague（同事类）：需要交互的对象，依赖中介者

数学表达：
设有N个对象，原始耦合度为O(N²)，引入中介者M后降为O(N)

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二、经典UML结构

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三、Unity实战代码（成就系统协调）

1. 定义中介者接口与同事基类

public interface IMediator {void Notify(object sender, string eventType, object data = null);
}public abstract class Colleague : MonoBehaviour {[SerializeField] protected IMediator mediator;public void SetMediator(IMediator mediator) {this.mediator = mediator;}
}

2. 实现具体同事类

// 成就系统
public class AchievementSystem : Colleague {public void Unlock(string achievementID) {Debug.Log($"解锁成就：{achievementID}");mediator?.Notify(this, "AchievementUnlocked", achievementID);}
}// UI弹窗系统
public class UIPopup : Colleague {public void ShowAchievementPopup(string title) {Debug.Log($"显示成就弹窗：{title}");}
}// 音效系统
public class SFXSystem : Colleague {public void Play(string clipName) {Debug.Log($"播放音效：{clipName}");}
}

3. 实现具体中介者

public class AchievementMediator : IMediator {private AchievementSystem _achievement;private UIPopup _popup;private SFXSystem _sfx;public AchievementMediator(AchievementSystem a, UIPopup u, SFXSystem s) {_achievement = a;_popup = u;_sfx = s;_achievement.SetMediator(this);_popup.SetMediator(this);_sfx.SetMediator(this);}public void Notify(object sender, string eventType, object data) {switch(eventType) {case "AchievementUnlocked":HandleAchievementUnlocked(data.ToString());break;case "PopupClosed":HandlePopupClosed();break;}}private void HandleAchievementUnlocked(string id) {_popup.ShowAchievementPopup(GetAchievementTitle(id));_sfx.Play("AchievementUnlocked");SaveSystem.SaveAchievement(id);}private void HandlePopupClosed() {_sfx.Play("ButtonClick");}
}

4. 客户端使用

public class GameManager : MonoBehaviour {[SerializeField] private AchievementSystem achievement;[SerializeField] private UIPopup popup;[SerializeField] private SFXSystem sfx;private IMediator _mediator;void Start() {_mediator = new AchievementMediator(achievement, popup, sfx);}void Update() {if(Input.GetKeyDown(KeyCode.A)) {achievement.Unlock("KILL_100_ENEMIES");}}
}

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四、模式进阶技巧

1. 事件总线集成

public class EventMediator : IMediator {private Dictionary<Type, List<Action<object>>> _handlers = new();public void Subscribe<T>(Action<T> handler) {var type = typeof(T);if(!_handlers.ContainsKey(type)) {_handlers[type] = new List<Action<object>>();}_handlers[type].Add(obj => handler((T)obj));}public void Notify(object sender, string eventType, object data) {if(_handlers.TryGetValue(data.GetType(), out var handlers)) {foreach(var h in handlers) h(data);}}
}

2. 状态依赖管理

public class StateDependentMediator : IMediator {private Dictionary<GameState, Action<object>> _stateHandlers = new();public void RegisterStateHandler(GameState state, Action<object> handler) {_stateHandlers[state] = handler;}public void Notify(object sender, string eventType, object data) {if(_stateHandlers.TryGetValue(GameManager.CurrentState, out var handler)) {handler(data);}}
}

3. 优先级路由

public class PriorityMediator : IMediator {private List<(int priority, Action<object>)> _handlers = new();public void AddHandler(int priority, Action<object> handler) {_handlers.Add((priority, handler));_handlers.Sort((a,b) => b.priority.CompareTo(a.priority));}public void Notify(object sender, string eventType, object data) {foreach(var h in _handlers) {h.handler(data);}}
}

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五、游戏开发典型应用场景

1. UI系统协调

   public class UIMediator : IMediator {public void Notify(object sender, string eventType) {switch(eventType) {case "InventoryOpened":PauseGame();HideHUD();break;case "SettingsClosed":ResumeGame();ShowHUD();break;}}
   }
   

2. 多人游戏同步

   public class NetworkMediator : IMediator {public void Notify(object sender, string eventType, object data) {switch(eventType) {case "PlayerMove":BroadcastToAllClients(data);break;case "ChatMessage":ProcessChatMessage(data);break;}}
   }
   

3. 任务系统协调

   public class QuestMediator : IMediator {public void Notify(object sender, string eventType, Quest quest) {switch(eventType) {case "QuestStarted":UpdateQuestLog();PlayQuestStartSFX();break;case "QuestCompleted":GrantRewards();UpdateNPCdialogue();break;}}
   }
   

4. 车辆控制系统

   public class VehicleMediator : IMediator {public void Notify(object sender, string eventType) {if(sender is Engine && eventType == "Overheat") {ThrottleControl.ReducePower();CoolingSystem.ActivateEmergencyCooling();}}
   }
   

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六、性能优化策略

策略	实现方式	适用场景
事件过滤	提前终止不相关事件处理	高频事件系统
批处理	合并多个通知为单个操作	物理系统更新
缓存路由表	预生成事件处理映射	固定事件类型
异步处理	使用UniTask处理耗时操作	网络通信场景

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七、模式对比与选择

维度	中介者模式	观察者模式
关注点	集中协调	松散通知
耦合度	同事类依赖中介者	发布者/订阅者解耦
复杂度	较高（需维护中介者）	较低
典型场景	复杂交互协调	简单事件通知

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八、最佳实践原则

1. 职责分离：避免中介者成为"上帝对象"
2. 接口最小化：

   public interface IGameMediator {void PlayerAction(PlayerActionType action);void UIEvent(UIEventType event);
   }
   

3. 模块化中介者：

   public class CompositeMediator : IMediator {private List<IMediator> _subMediators = new();public void AddMediator(IMediator m) => _subMediators.Add(m);public void Notify(object sender, string eventType, object data) {foreach(var m in _subMediators) m.Notify(sender, eventType, data);}
   }
   

4. 异常隔离：

   public void Notify(...) {try {// 处理逻辑} catch(Exception e) {Debug.LogError($"中介者处理异常：{e.Message}");}
   }
   

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九、常见问题解决方案

Q1：如何防止中介者过度膨胀？
→ 实现分层中介者

public class HierarchyMediator : IMediator {private Dictionary<SystemType, IMediator> _subMediators = new();public void Notify(...) {if(_subMediators.TryGetValue(GetSystemType(sender), out var mediator)) {mediator.Notify(sender, eventType, data);}}
}

Q2：如何处理循环通知？
→ 实现事件标记

public class Notification {public string Type;public bool IsProcessed;
}public void Notify(...) {if(notification.IsProcessed) return;notification.IsProcessed = true;// 处理逻辑
}

Q3：如何调试复杂事件流？
→ 实现事件追踪器

public class DebugMediator : IMediator {public void Notify(object sender, string eventType, object data) {Debug.Log($"[{Time.time}] 事件：{eventType} 发送者：{sender.GetType().Name}");// 传递给实际中介者...}
}

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