unity+Loom实现多线程（Thread）和主线程（MainThread）交互

女爷i 2022-06-05 12:27 349阅读 0赞

最近在做资源更新时，需要显示现在的进度调。我在Unity中开启了一个线程来做下载任务，然后实时刷新下载进度。然后Unity报了一个错误。  
get\_isActiveAndEnabled can only be called from the main thread.

意思是Unity中的组件只能运行在Unity的主线程中，无法在新开的线程中调用Unity的组件。

用Loom实现多线程与主线程交互

using UnityEngine;
    using System.Collections;
    using System.Collections.Generic;
    using System;
    using System.Threading;
    using System.Linq;
    
        public class Loom :MonoBehaviour
        {
            public static int maxThreads = 8;
            static int numThreads;
    
            private static Loom _current;
            //private int _count;
            public static Loom Current
            {
                get
                {
                    Initialize();
                    return _current;
                }
            }
    
            void Awake()
            {
                _current = this;
                initialized = true;
            }
    
            static bool initialized;
    
            public static void Initialize()
            {
                if (!initialized)
                {
    
                    if (!Application.isPlaying)
                        return;
                    initialized = true;
                    var g = new GameObject("Loom");
                    _current = g.AddComponent<Loom>();
    #if !ARTIST_BUILD
                    UnityEngine.Object.DontDestroyOnLoad(g);
    #endif
                }
    
            }
            public struct NoDelayedQueueItem
            {
                public Action<object> action;
                public object param;
            }
    
            private List<NoDelayedQueueItem> _actions = new List<NoDelayedQueueItem>();
            public struct DelayedQueueItem
            {
                public float time;
                public Action<object> action;
                public object param;
            }
            private List<DelayedQueueItem> _delayed = new List<DelayedQueueItem>();
    
            List<DelayedQueueItem> _currentDelayed = new List<DelayedQueueItem>();
    
            public static void QueueOnMainThread(Action<object> taction, object tparam)
            {
                QueueOnMainThread(taction, tparam, 0f);
            }
            public static void QueueOnMainThread(Action<object> taction, object tparam, float time)
            {
                if (time != 0)
                {
                    lock (Current._delayed)
                    {
                        Current._delayed.Add(new DelayedQueueItem { time = Time.time + time, action = taction, param = tparam });
                    }
                }
                else
                {
                    lock (Current._actions)
                    {
                        Current._actions.Add(new NoDelayedQueueItem { action = taction, param = tparam });
                    }
                }
            }
    
            public static Thread RunAsync(Action a)
            {
                Initialize();
                while (numThreads >= maxThreads)
                {
                    Thread.Sleep(100);
                }
                Interlocked.Increment(ref numThreads);
                ThreadPool.QueueUserWorkItem(RunAction, a);
                return null;
            }
    
            private static void RunAction(object action)
            {
                try
                {
                    ((Action)action)();
                }
                catch
                {
                }
                finally
                {
                    Interlocked.Decrement(ref numThreads);
                }
    
            }
    
    
            void OnDisable()
            {
                if (_current == this)
                {
    
                    _current = null;
                }
            }
    
    
    
            // Use this for initialization
            void Start()
            {
    
            }
    
            List<NoDelayedQueueItem> _currentActions = new List<NoDelayedQueueItem>();
    
            // Update is called once per frame
            void Update()
            {
                if (_actions.Count > 0)
                {
                    lock (_actions)
                    {
                        _currentActions.Clear();
                        _currentActions.AddRange(_actions);
                        _actions.Clear();
                    }
                    for (int i = 0; i < _currentActions.Count; i++)
                    {
                        _currentActions[i].action(_currentActions[i].param);
                    }
                }
    
                if (_delayed.Count > 0)
                {
                    lock (_delayed)
                    {
                        _currentDelayed.Clear();
                        _currentDelayed.AddRange(_delayed.Where(d => d.time <= Time.time));
                        for (int i = 0; i < _currentDelayed.Count; i++)
                        {
                            _delayed.Remove(_currentDelayed[i]);
                        }
                    }
    
                    for (int i = 0; i < _currentDelayed.Count; i++)
                    {
                        _currentDelayed[i].action(_currentDelayed[i].param);
                    }
                }
            }
        }

未使用Loom报错方法

public Text mText;
        void Start () 
        {
            Thread thread = new Thread(RefreshText);
            thread.Start();
        }
    
        void Update () 
        {
    
        }
        private void RefreshText()
        {
            mText.text = "Hello Loom!";
        }

更改后

using UnityEngine;
    using System.Collections;
    using UnityEngine.UI;
    using System.Threading;
    public class testLoom : MonoBehaviour
    {
    
        public Text mText;
        void Start () 
        {
    
            // 用Loom的方法调用一个线程
            Loom.RunAsync(
                () =>
                {
                    Thread thread = new Thread(RefreshText);
                    thread.Start();
                }
                );
        }
    
        void Update () 
        {
    
        }
        private void RefreshText()
        {  
            // 用Loom的方法在Unity主线程中调用Text组件
            Loom.QueueOnMainThread((param) =>
                {
                    mText.text = "Hello Loom!";
                },null);
        }
    }