C#状态机

状态机可以拆分复杂的控制逻辑到各个状态之中，使之更加清晰，更容易理解
以下是在UNITY3D中的一个实现

using System.Collections;
/// <summary>
/// 基于字符串标识状态的状态机
/// 请自行确保FSMStatus的Name的唯一性
/// </summary>
public class FSM {

FSMStatus curStatus;
// Use this for initialization
public FSM(){
var t = CoroutineWrapper.Inst;
t.OnPerFrame += Update;
}

// Update is called once per frame
void Update () {
if (curStatus != null) {
curStatus.Update();
}
}

public void SetStatus(FSMStatus status) {
if (curStatus!=null) {
curStatus.Out();
}
curStatus = status;
curStatus.In();
}
}

using System.Collections;
/// <summary>
/// 基于字符串标识的状态机状态
/// </summary>
public interface FSMStatus {
string Name {
get;
}
// Use this for initialization
void In();

// Update is called once per frame
void Update();

void Out();
}

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

public class CoroutineWrapper : MonoBehaviour {
#region 单例
static CoroutineWrapper inst;
private readonly static object mutex = new object();
public static CoroutineWrapper Inst {
get {
lock (mutex) {
if (inst == null) {
var obj = new GameObject("CoroutineWrapper");
inst = obj.AddComponent<CoroutineWrapper>();
}
return inst;
}
}
}
void Awake() {
inst = this;
DontDestroyOnLoad(this);
}
#endregion
public IEnumerator ExeDelay(int frames,Action ev) {
for (int i = 0; i < frames;i++ ) {
yield return new WaitForEndOfFrame();
}
ev();
}
public IEnumerator ExeDelayS(float sec, Action ev) {
yield return new WaitForSeconds(sec);
ev();;
}
public static void EXES(float sec, Action ev) {
inst.StartCoroutine(inst.ExeDelayS(sec,ev));
}
public static void EXEF(int frames, Action ev) {
inst.StartCoroutine(inst.ExeDelay(frames, ev));
}
public static void EXEE(Func<IEnumerator> ien) {
inst.StartCoroutine(ien());
}
public static void EXEE(Func<object[],IEnumerator> ien,params object[] p) {
inst.StartCoroutine(ien(p));
}
public event Action OnPerFrame;
void Update() {
if (OnPerFrame != null)
OnPerFrame();
}
}


使用时，可以跟据自己的需要去编写实现了FSMStatus接口类，来表示各个状态，然后状态间的跳转就被分散到了每个状态的代码之中