状态机一般情况下只有两个类：状态基类以及管理状态的类。
状态机主要用于AI或者场景切换(不同场景对应的就是游戏的不同状态)，当然，这只是本人的想法。

using UnityEngine;  
using System.Collections;  
  
public abstract class State {  
  
    public int ID { set; get; }  
    public Transform TargetTra { set; get; }  
    public StateMachine StateMac { set; get; }  
  
    public virtual void Enter() { }  
    public virtual void Execute() { }  
    public virtual void Exit() { }  
}  

using UnityEngine;  
using System.Collections;  
using System.Collections.Generic;  
  
public class StateMachine {  
  
    public Dictionary<int, State> dictionary = new Dictionary<int,State>();  
    public State CurrentState { set; get; }  
  
    public State GetState(int id)  
    {  
        if (dictionary.ContainsKey(id))  
            return dictionary[id];  
        else  
            return null;  
    }  
  
    public void AddState(State state)  
    {  
        int id = state.ID;  
        if (!dictionary.ContainsKey(id))  
            dictionary.Add(id, state);  
    }  
  
    public void RemoveState(int id)  
    {  
        if (dictionary.ContainsKey(id))  
            dictionary.Remove(id);  
    }  
  
    public void InitState(int id)  
    {  
        if (CurrentState == null)  
        {  
            CurrentState = dictionary[id];  
            CurrentState.Enter();  
        }  
    }  
  
    public void ChangeState(int id)  
    {  
        if (CurrentState.ID != id)  
        {  
            CurrentState.Exit();  
            CurrentState = dictionary[id];  
            CurrentState.Enter();  
        }  
    }  
  
    public void ExecuteState()  
    {  
        CurrentState.Execute();  
    }  
  
    public bool CheckState(int id)  
    {  
        return CurrentState.ID == id;  
    }    
}  

当编写具体的一个状态时，可以这样：

using UnityEngine;  
using System.Collections;  
  
public class RotateState : State {  
  
    public RotateState(Transform targetTra, StateMachine sm)  
    {  
        ID = (int)CharacterState.rotate;  
        TargetTra = targetTra;  
        StateMac = sm;  
    }  
  
    public override void Enter()  
    {  
        base.Enter();  
        Debug.Log("进入旋转状态");  
        TargetTra.GetComponent<MeshRenderer>().material.color = Color.green;  
    }  
  
    public override void Execute()  
    {  
        base.Execute();  
        TargetTra.transform.Rotate(Vector3.up);  
    }  
  
    public override void Exit()  
    {  
        base.Exit();  
        Debug.Log("退出旋转状态");  
        TargetTra.transform.localScale = new Vector3(2, 2, 2);  
    }  
}  

测试代码：

using UnityEngine;  
using System.Collections;  
  
public class Player : MonoBehaviour {  
  
    StateMachine stateMachine = new StateMachine();  
  
    void Start ()   
    {  
        stateMachine.AddState(new RotateState(transform, stateMachine));  
        stateMachine.AddState(new RunState(transform, stateMachine));  
        stateMachine.InitState(((int)CharacterState.rotate));  
    }  
      
    void Update ()   
    {  
        stateMachine.ExecuteState();  
    }  
  
    void OnGUI()  
    {  
        if (GUILayout.Button("旋转状态"))  
        {  
            stateMachine.ChangeState((int)CharacterState.rotate);  
        }  
  
        if (GUILayout.Button("行走状态"))  
        {  
            stateMachine.ChangeState((int)CharacterState.run);  
        }  
    }  
}  

效果图：

文章转自：http://blog.csdn.net/lyh916/article/details/46011715