Unity编辑器中何时需要协程

当我们定制Unity编辑器的时候,往往需要启动额外的协程或者线程进行处理。比如当执行一些界面更新的时候,需要大量计算,如果用户在不断修正一个参数,比如从1变化到2,这种变化过程要经历无数中间步骤,调用N多次Update,如果直接在Update中不断刷新,界面很容易直接卡死。所以在一个协程中进行一些优化,只保留用户最后一次参数修正,省去中间步骤,就会好很多。这属于Unity编辑器的内容,也属于优化的内容,还是放在优化中吧。

解决问题思路

Unity官网的questions里面也有很多人在搜索这个问题,不过后来是看到有个人提到了这个方法。问题的关键点就是“EditorApplication.update ”,有个这样的方法,你把要执行的协程传递给它就可以在编辑器下自动执行循环调用。

老外的写法

当然,后来我也找到一个老外的写法,代码贴出来如下:

using UnityEngine;
using UnityEditor;
using System.Collections;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
public static class EditorCoroutineRunner
{
    private class EditorCoroutine : IEnumerator
    {
        private Stack<IEnumerator> executionStack;
        public EditorCoroutine(IEnumerator iterator)
        {
            this.executionStack = new Stack<IEnumerator>();
            this.executionStack.Push(iterator);
        }
        public bool MoveNext()
        {
            IEnumerator i = this.executionStack.Peek();
            if (i.MoveNext())
            {
                object result = i.Current;
                if (result != null && result is IEnumerator)
                {
                    this.executionStack.Push((IEnumerator)result);
                }
                return true;
            }
            else
            {
                if (this.executionStack.Count > 1)
                {
                    this.executionStack.Pop();
                    return true;
                }
            }
            return false;
        }
        public void Reset()
        {
            throw new System.NotSupportedException("This Operation Is Not Supported.");
        }
        public object Current
        {
            get { return this.executionStack.Peek().Current; }
        }
        public bool Find(IEnumerator iterator)
        {
            return this.executionStack.Contains(iterator);
        }
    }
    private static List<EditorCoroutine> editorCoroutineList;
    private static List<IEnumerator> buffer;
    public static IEnumerator StartEditorCoroutine(IEnumerator iterator)
    {
        if (editorCoroutineList == null)
        {
            editorCoroutineList = new List<EditorCoroutine>();
        }
        if (buffer == null)
        {
            buffer = new List<IEnumerator>();
        }
        if (editorCoroutineList.Count == 0)
        {
            EditorApplication.update += Update;
        }
        // add iterator to buffer first
        buffer.Add(iterator);
        return iterator;
    }
    private static bool Find(IEnumerator iterator)
    {
        // If this iterator is already added
        // Then ignore it this time
        foreach (EditorCoroutine editorCoroutine in editorCoroutineList)
        {
            if (editorCoroutine.Find(iterator))
            {
                return true;
            }
        }
        return false;
    }
    private static void Update()
    {
        // EditorCoroutine execution may append new iterators to buffer
        // Therefore we should run EditorCoroutine first
        editorCoroutineList.RemoveAll
        (
            coroutine => { return coroutine.MoveNext() == false; }
        );
        // If we have iterators in buffer
        if (buffer.Count > 0)
        {
            foreach (IEnumerator iterator in buffer)
            {
                // If this iterators not exists
                if (!Find(iterator))
                {
                    // Added this as new EditorCoroutine
                    editorCoroutineList.Add(new EditorCoroutine(iterator));
                }
            }
            // Clear buffer
            buffer.Clear();
        }
        // If we have no running EditorCoroutine
        // Stop calling update anymore
        if (editorCoroutineList.Count == 0)
        {
            EditorApplication.update -
用法就是大概在你自己的类的Start方法中稍作修改,再增加一个协程函数,如下:
        void Start()
        {
            rope = gameObject.GetComponent<QuickRope>();
            #if UNITY_EDITOR
            //调用方法
            EditorCoroutineRunner.StartEditorCoroutine(OnThreadLoop());
            #endif
        }
        public IEnumerator OnThreadLoop()
        {
            while(true)
            {
                Debug.Log("Looper");
                yield return null;
            }
        }
当然最好是加上#if UNITY_EDITOR预处理了。这个类基本是满足要求了。如果你把你自己的脚本做了这样的修改之后,它是可以在编辑状态不断执行到Loop的,要注意它需要先执行到Start,也就是说,你可能需要把GameObject做成Prefab,然后把它从场景中删除,再把Prefab拖回场景,才会在编辑状态下触发脚本上的Star方法,从而激发Loop。
我的写法
然而,用久了你就会发现几个问题,一旦Loop开始了,你是无法停止的,哪怕你把GameObject从场景中删掉都无济于事,当然隐藏也没有效果。为了解决这个问题,也把脚本弄得简单点儿,我重写了这个脚本,希望需要的同学可以愉快地使用。
using UnityEngine;
using UnityEditor;
using System.Collections;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
public static class EditorCoroutineLooper
{
    private static Dictionary<IEnumerator,MonoBehaviour> m_loopers = new Dictionary<IEnumerator,MonoBehaviour> ();
    private static bool M_Started = false;
    /// <summary>
    /// 开启Loop
    /// </summary>
    /// <param name="mb">脚本</param>
    /// <param name="iterator">方法</param>
    public static void StartLoop(MonoBehaviour mb, IEnumerator iterator)
    {
        if(mb!=null && iterator != null)
        {
            if(!m_loopers.ContainsKey(iterator))
            {
                m_loopers.Add(iterator,mb);
            }
            else
            {
                m_loopers[iterator]=mb;
            }
        }
        if (!M_Started)
        {
            M_Started = true;
            EditorApplication.update += Update;
        }
    }
    private static List<IEnumerator> M_DropItems=new List<IEnumerator>();
    private static void Update()
    {
        if (m_loopers.Count > 0)
        {
            var allItems = m_loopers.GetEnumerator();
            while(allItems.MoveNext())
            {
                var item = allItems.Current;
                var mb = item.Value;
                //卸载时丢弃Looper
                if(mb == null)
                {
                    M_DropItems.Add(item.Key);
                    continue;
                }
                //隐藏时别执行Loop
                if(!mb.gameObject.activeInHierarchy)
                {
                    continue;
                }
                //执行Loop,执行完毕也丢弃Looper
                IEnumerator ie = item.Key;
                if(!ie.MoveNext())
                {
                    M_DropItems.Add(item.Key);
                }
            }
            //集中处理丢弃的Looper
            for(int i = 0;i < M_DropItems.Count;i++)
            {
                if(M_DropItems[i] != null)
                {
                    m_loopers.Remove(M_DropItems[i]);
                }
            }
            M_DropItems.Clear();
        }
        if (m_loopers.Count == 0)
        {
            EditorApplication.update -= Update;
            M_Started = false;
        }
    }
}
//调用方法原来这个样
            EditorCoroutineRunner.StartEditorCoroutine(OnThreadLoop());
//现在改成这个样
            EditorCoroutineLooper.StartLoop(this,OnThreadLoop());
使用这个脚本的时候,需要传两个参数,一个就是你自己的脚本,另外一个就是协程函数。原理就是代码里面会检测你的脚本状态,当脚本关闭或者卸载的时候,都会停掉Loop调用。老外有时候写代码,也不那么讲究,有没有?