将状态模式运用到场景切换得功能当中

首先创建一个脚本GameLoop 这个脚本需要挂到游戏物体上，用来控制场景得切换和更新。
GameLoop脚本得代码

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

public class GameLoop : MonoBehaviour
{
    private SceneController controller = null;
    private void Awake()
    {
        DontDestroyOnLoad(this.gameObject);
    }
    // Use this for initialization
    void Start () {
        controller = new SceneController();
        controller.SetState(new StartScene(controller),false);
	}
	
	// Update is called once per frame
	void Update ()
    {
        controller.StateUpdate();
	}
}

接着比如有三个场景要进行切换，则需要有三个分别控制得脚本，再建立一个接口，让这三个场景都继承这个接口
ISceneState接口代码

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

public class ISceneState {

    private string mSceneName;
    public SceneController mController;
    public ISceneState(string sceneName, SceneController controller)
    {
        mSceneName = sceneName;
        mController = controller;
    }

    public string SceneName
    {
        get { return mSceneName; }

    }
    //每次进入到这个状态得时候调用
    public virtual void StateUpdate()
    {

    }
    public virtual void StateStart()//这个方法可能会用在当场景进入的时候使用，进行初始化
    {

    }
    public virtual void StateEnd()//这个方法可能会用在当场景切换到其他场景时做一些释放的工作
    {

    }
}

开始场景代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using UnityEngine.UI;
using UnityEngine;
public class StartScene:ISceneState
{
    public StartScene(SceneController controller) : base("startScene", controller)
    {

    }
    private Image mLogo;
    private float mSmoothingSpeed = 2;
    private float mWaitTime = 2;
    public override void StateStart()
    {
        mLogo = GameObject.Find("Logo").GetComponent();
        mLogo.color = Color.black;
    }
    public override void StateUpdate()
    {
        mLogo.color = Color.Lerp(mLogo.color, Color.white, mSmoothingSpeed * Time.deltaTime);
        mWaitTime -= Time.deltaTime;
        if (mWaitTime <= 0)
        {
            mController.SetState(new MainMenuScene(mController));    
        }
    }
}

菜单按钮场景代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using UnityEngine;
using UnityEngine.UI;
class MainMenuScene : ISceneState
{
    public MainMenuScene(SceneController controller):base("menuScene",controller)
    {

    }
    public override void StateStart()
    {
        GameObject.Find("StartButton").GetComponent().onClick.AddListener(() =>
        {
            mController.SetState(new BattleScene(mController));

        });
    }
    private void OnStartButtonClick()
    {
        mController.SetState(new BattleScene(mController));
    }
}

战斗场景代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;


class BattleScene:ISceneState
{
    public BattleScene(SceneController controller):base("battleScene",controller)
    {
    }
}

最后还需要一个 场景控制者，代码如下

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

public class SceneController
{
    private ISceneState mState;
    private AsyncOperation mAo;

    private bool mIsRunStart = false;
    public void SetState(ISceneState state,bool isLoadScene =true)
    {
        if (mState != null)
        {
            mState.StateEnd();//让上一个场景状态做一下清理工作
        }
        mState = state;
        if (isLoadScene)
        {
            mAo = SceneManager.LoadSceneAsync(mState.SceneName);
            mIsRunStart = false;
        }
        else
        {
            mState.StateStart();
            mIsRunStart = true;
        }
    }
    

    public void StateUpdate()
    {
        if (mAo != null && mAo.isDone == false) return;
        //mIsRunStart 是否加载完成
        if (mIsRunStart == false&& mAo != null && mAo.isDone == true)
        {
            mState.StateStart();
            mIsRunStart = true;
        }
        if (mState != null)
        {
            mState.StateUpdate();
        }
    }
    
}