有限状态机简单实现

namespace FSM
{
    public class State
    {
        //指明当前状态机被哪个状态机所管理
        public StateMachine stateMachine;

        //三种状态
        public virtual void EnterState()
        {
        }
        public virtual void UpadateState()
        {
        }
        public virtual void ExitState()
        {
        }
    }

    //吃饭状态
    public class EatState : State
    {
        public override void EnterState()
        {
            Debug.Log("饭前洗手");
        }
        public override void UpadateState()
        {
            Debug.Log("吃饭中");
            if (Input.GetKeyDown(KeyCode.A))
            {
                stateMachine.ChangeState("Study");
            }
        }
        public override void ExitState()
        {
            Debug.Log("饭后甜点");
        }
    }

    //睡觉状态
    public class SleepState : State
    {
        public override void EnterState()
        {
            Debug.Log("睡前洗漱");
        }

        public override void UpadateState()
        {
            Debug.Log("睡觉中zzzZZZZ");
            if (Input.GetKeyDown(KeyCode.A))
            {
                stateMachine.ChangeState("Eat");
            }
        }
        public override void ExitState()
        {
            Debug.Log("睡醒了");

        }
    }

    //学习状态
    public class StudyState : State
    {
        public override void EnterState()
        {
            Debug.Log("学前准备");
        }

        public override void UpadateState()
        {
            Debug.Log("学习中");
            if (Input.GetKeyDown(KeyCode.A))
            {
                stateMachine.ChangeState("Sleep");
            }
        }
        public override void ExitState()
        {
            Debug.Log("下班");
        }
    }

    public class StateMachine
    {
        //自定义一个key值即状态名   对应一个行为状态
        private Dictionary _stateDic = new Dictionary();
        private State _currentState;


        //注册   对应新动画系统中  把动画剪辑拖入到窗口中
        public void Register(string key, State state)
        {
            state.stateMachine = this;
            _stateDic.Add(key, state);
        }
        //设置默认  对应新动画系统中 右键选择起始状态
        public void SetDefault(string stateName)
        {

            if (_stateDic.ContainsKey(stateName))
            {
                _currentState = _stateDic[stateName];
                _currentState.EnterState();
            }
        }
        //改变  对应新动画系统中  状态之间的连线  处理状态之间的切换
        public void ChangeState(string stateName)
        {
            if (_currentState != null)
            {
                _currentState.ExitState();
            }
            if (_stateDic.ContainsKey(stateName))
            {
                _currentState = _stateDic[stateName];
                _currentState.EnterState();
            }
        }
        //状态机执行
        public void DoWork()
        {
            if (_currentState != null) 
            {
                _currentState.UpadateState();
            }
        }
    }
}

状态机的添加和调用

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

public class TestFSM : MonoBehaviour {

    StateMachine stateMachine;

	// Use this for initialization
	void Start () {
        stateMachine = new StateMachine();
        stateMachine.Register("Sleep", new FSM.SleepState());
        stateMachine.Register("Eat", new FSM.EatState());
        stateMachine.Register("Study", new FSM.StudyState());
        stateMachine.SetDefault("Sleep");

    }
	
	// Update is called once per frame
	void Update () {
        stateMachine.DoWork();
	}
}