出处：
author：孙广东 时间：2015.3.25
关于状态机这种设计模式不用多介绍了，网上有很多这方面的介绍，特别是FSM。
现在是我实现一个轻量级的状态机。
using System;using System.Collections.Generic;namespace Gamelogic{/**一个轻量级的状态机。要使用它：-# 定义您自己的label。枚举Enums可能是最好的选择。-# 构造一个新的状态机state machin，通常是在 MonoBehaviour 的Start方法中。-# 添加的各种状态和对应的delegates。-# 从 MonoBehaviour 的Update方法调用状态机Update方法。-# 在状态机transition转换状态时调用 ChangeState 方法（你可以调用此方法，从一个state delegates，，或任何其他地方）-# 状态发生变化时，对现有状态执行关闭 OnStop，然后OnStart开启新状态，之后新的状态每帧更新中调用 OnUpdate 方法*/public sealed class StateMachine<TLabel>{private class State{public readonly Action onStart;public readonly Action onUpdate;public readonly Action onStop;public readonly TLabel label;public State(TLabel label, Action onStart, Action onUpdate, Action onStop){this.onStart = onStart;this.onUpdate = onUpdate;this.onStop = onStop;this.label = label;}}private readonly Dictionary<TLabel, State> stateDictionary;private State currentState;/**Returns the label of the current state.*/public TLabel CurrentState{get { return currentState.label; }/**@version1_2*/set { ChangeState(value); }}/**Constructs a new StateMachine.*/public StateMachine(){stateDictionary = new Dictionary<TLabel, State>();}/**Adds a state, and the delegates that should runwhen the state starts, stops,and when the state machine is updated.Any delegate can be null, and wont be executed.*/public void AddState(TLabel label, Action onStart, Action onUpdate, Action onStop){stateDictionary[label] = new State(label, onStart, onUpdate, onStop);}/**Changes the state from the existing one to the state with the given label.*/private void ChangeState(TLabel newState){if (currentState != null && currentState.onStop != null){currentState.onStop();}currentState = stateDictionary[newState];if (currentState.onStart != null){currentState.onStart();}}/**This method should be called every frame. */public void Update(){if (currentState != null && currentState.onUpdate != null){currentState.onUpdate();}}}}
使用的例子 很简单，cube的两种状态转换。 每种状态有不同的行为表现：
using System.Collections;using UnityEngine;namespace Gamelogic.Examples{public class Cube : MonoBehaviour {public enum CubeStates {Swivel,MoveStraight}private StateMachine<CubeStates> stateMachine;private float moveSpeed = 1;private float switchTime = 3; private float swivelSpeed = 2;public void Start(){stateMachine = new StateMachine<CubeStates>();stateMachine.AddState(CubeStates.Swivel, OnSwivelStart, OnSwivelUpdate, OnSwivelStop);stateMachine.AddState(CubeStates.MoveStraight, null, OnMoveStraightUpdate, null);stateMachine.CurrentState = CubeStates.MoveStraight;StartCoroutine(SwitchStates());}public IEnumerator SwitchStates(){while (true){stateMachine.CurrentState = CubeStates.Swivel;yield return new WaitForSeconds(switchTime);stateMachine.CurrentState = CubeStates.MoveStraight;yield return new WaitForSeconds(switchTime);}}public void Update(){stateMachine.Update();}public void OnGUI(){GUILayout.TextField(stateMachine.CurrentState.ToString());}public void OnMoveStraightUpdate(){float dx = -Time.deltaTime * moveSpeed;transform.TranslateX(dx);}public void OnSwivelUpdate(){float dx = Time.deltaTime*moveSpeed;float y = Mathf.Sin(swivelSpeed * transform.position.x * 2 * Mathf.PI/switchTime);transform.TranslateX(dx);transform.SetY(y);}public void OnSwivelStart(){GetComponent<Renderer>().material.color = Color.red;}public void OnSwivelStop(){GetComponent<Renderer>().material.color = Color.green;transform.SetY(0); //recallibrate}}}就是这样的很简单的状态机。
我爱你….为了你的幸福，我愿意放弃一切—包括你。
