Unity FSM finite state machine framework

 FSMStateManager

Manage FSMState state

Determine how many states there are during initialization, and add states afterward.

Then call the callback of the RunState running state, running state.

using UnityEngine;

public class FSMStateManager
{
    private FSMState[] states;

    public FSMStateManager(int stateCount)
    {
        Initial(stateCount);
    }

    /// <summary>
    /// 初始化
    /// </summary>
    /// <param name="stateCount"></param>
    private void Initial(int stateCount)
    {
        states = new FSMState[stateCount];
    }

    /// <summary>
    /// 状态的边界【最后添加的一个状态的下标】
    /// </summary>
    private sbyte countBorder = -1;

    /// <summary>
    /// 当前状态的下标
    /// </summary>
    private sbyte currentIndex = -1;

    /// <summary>
    /// 添加状态
    /// </summary>
    /// <param name="state"></param>
    public void AddState(FSMState state)
    {
        countBorder++;

        if (countBorder > states.Length - 1)
        {
            Debug.Log("添加状态失败，状态已满！");
            
            return;
        }

        states[countBorder] = state;
    }

    /// <summary>
    /// 运行状态
    /// </summary>
    /// <param name="index"></param>
    public void RunState(int index)
    {
        // 如果当前状态已经运行
        if (currentIndex == index)
        {
            return;
        }
        
        // 如果已经有状态在运行
        if (currentIndex != -1)
        {
            states[currentIndex].OnExit();
        }

        currentIndex = (sbyte)index;
        
        // 运行新的状态
        states[currentIndex].OnEnter();
    }

    /// <summary>
    /// 当前状态更新
    /// </summary>
    public void CurrentStateUpdate()
    {
        // 如果当前没有状态
        if (currentIndex == -1)
        {
            return;
        }
        
        states[currentIndex].OnStay();
    }

    /// <summary>
    /// 当前状态
    /// </summary>
    /// <returns></returns>
    public int CurrentState()
    {
        return currentIndex;
    }
}

FSMState

base class for state

Provides entry, stay, and exit callbacks for subclasses to override.

public class FSMState
{
    /// <summary>
    /// 进入状态
    /// </summary>
    public virtual void OnEnter()
    {}
    
    /// <summary>
    /// 状态中
    /// </summary>
    public virtual void OnStay()
    {}
    
    /// <summary>
    /// 退出状态
    /// </summary>
    public virtual void OnExit()
    {}
}