实用的信号系统

在项目中信号系统（或者事件系统）用的非常多，而且很好用，我喜欢用于全局信号，用于不同系统之间的交互，加上MVC，ECS模块的内部信号。

以下列出实现的内容：

SignalCenter：全局的信号中心用于交互不同系统之间的消息

EntitySignal（下面没有，实际上就是换个名字，并且不是静态类）：实体内部信号，我常用于MVC结构，或者ECS结构的内部信号，比如数据跟UI的交互，UI监听数据，系统监听UI点击事件之类的

SignalParam：信号的参数，用于扩展传递复杂数据

具体实现

using UnityEngine;
using UnityEngine.Events;
using System.Collections;
using System.Collections.Generic;

/// <summary>
/// event
/// </summary>
[System.Serializable]
public class Signal : UnityEvent<SignalParam> { }


/// <summary>
/// 信号行为参数
/// </summary>
public class SignalParam {
    public int intVal;
    public string stringVal;
    public Dictionary<int, int> dicVal;
    public List<int> listVal;
    public GameObject gameObjectVal;
    // 自己扩展其他的参数
}

/// <summary>
/// 消息中心
/// </summary>
public class SignalCenter
{
    // 单例模式
    public static SignalCenter instance;

    // 信号表
    private Dictionary<string, Signal> eventDictionary = new Dictionary<string, Signal>();

    private static SignalParam onceParam { get; set; } // 简单信号参数，内部扩展接口，注意引用
    /// <summary>
    /// 开始监听，注册信号
    /// </summary>
    /// <param name="signalName">Event name.</param>
    /// <param name="signalAction">signalAction.</param>
    public static void Connect(string signalName, UnityAction<SignalParam> signalAction)
    {
        if (instance == null)
        {
            instance = new SignalCenter();
            if (instance == null)
            {
                Debug.Log("Have no event manager on scene");
                return;
            }
        }
        Signal signal = null;
        if (instance.eventDictionary.TryGetValue(signalName, out signal))
        {
            signal.AddListener(signalAction);
        }
        else
        {
            signal = new Signal();
            signal.AddListener(signalAction);
            instance.eventDictionary.Add(signalName, signal);
        }
    }

    /// <summary>
    /// 断开监听，取消信号
    /// </summary>
    /// <param name="signalName">Event name.</param>
    /// <param name="signalAction">signalAction.</param>
    public static void Disconnect(string signalName, UnityAction<SignalParam> signalAction)
    {
        if (instance == null)
        {
            return;
        }
        Signal signal = null;
        if (instance.eventDictionary.TryGetValue(signalName, out signal))
        {
            signal.RemoveListener(signalAction);
        }
    }

    /// <summary>
    /// 发送信号，触发
    /// </summary>
    /// <param name="signalName">Event name.</param>
    /// <param name="obj">Object.</param>
    /// <param name="param">Parameter.</param>
    public static void Emit(string signalName, SignalParam param)
    {
        if (instance == null)
        {
            return;
        }
        Signal signal = null;
        if (instance.eventDictionary.TryGetValue(signalName, out signal))
        {
            signal.Invoke(param);
        }
    }

    /// <summary>
    /// 简单发送信号，整形参数
    /// </summary>
    /// <param name="signalName">Event name.</param>
    /// <param name="obj">Object.</param>
    /// <param name="param">Parameter.</param>
    public static void Emit(string signalName, int intval)
    {
        if (instance == null)
        {
            return;
        }
        Signal signal = null;
        onceParam.intVal = intval;
        if (instance.eventDictionary.TryGetValue(signalName, out signal))
        {
            signal.Invoke(onceParam);
        }
    }
}