unity使用线程下载文件，支持断点续传

用一个简单的滑动条来显示下载进度
支持断点续传
滑动条部分代码

using UnityEngine;
using UnityEngine.UI;

public class LodingManager : MonoBehaviour
{
    public Transform[] its;
    public float speed;

    public Transform sli;
    public Text text;
    private float processing;
    HTTPDownLoad downLoad;

    private void Start()
    {
        string s = "https://qd.myapp.com/myapp/qqteam/pcqq/PCQQ2019.exe";
        DownLoadFile(s);
    }
    public void DownLoadFile(string url)//下载指定文件
    {
        processing = 0;
        downLoad = new HTTPDownLoad(url, Application.dataPath + "/DownLoad/", 5000);
    }
    void Update()
    {
        foreach (Transform item in its)
        {
            item.localPosition += new Vector3(Time.deltaTime, 0) * speed;

            if (item.localPosition.x > 700)
            {
                item.localPosition -= new Vector3(92.376f * 16, 0);
            }
        }

        if (downLoad.Status == 0)//更新进度条
        {
            Pro = downLoad.Progress;
        }
        if (Input.GetKeyDown(KeyCode.Space))//按空格键下载其他文件
        {
            string s = "https://dldir1.qq.com/music/clntupate/QQMusic_YQQWinPCDL.exe";
            DownLoadFile(s);
        }
        if (Input.GetKeyDown(KeyCode.Escape))//按返回键暂停下载
        {
            downLoad.Close();
        }
    }


    public float Pro
    {
        get
        {
            return processing;
        }
        set
        {
            if (value < 1)
            {
                while (processing < value)//为什么这么处理呢，让滑动条更平顺的移动
                {
                    processing += 0.01f;
                    text.text = (int)(100 * processing) + "%";
                    if (processing <= 1)
                        sli.localPosition = new Vector3(-1152 + 1152 * processing, 0);
                }
            }
            else if (value == 1)
            {
                text.text = "100%";
                sli.localPosition = new Vector3(0, 0);
            }
        }
    }
}

下载的代码

using System;
using System.Net;
using System.IO;
using System.Threading;
using UnityEngine;
/// <summary>
/// 文件下载
/// </summary>
public class HTTPDownLoad
{
    private string postfix = ".temp";//临时文件后缀名
    // 下载进度
    public float Progress
    {
        get;
        private set;
    }
    // 状态 0 正在下载 1 下载完成 -1 下载出错
    public int Status
    {
        get;
        private set;
    }
    // 错误信息
    public string Error
    {
        get;
        set;
    }
    // 总长度
    public long TotalLength
    {
        get;
        private set;
    }
    // 保存路径
    private string savePath;
    // url地址
    private string url;
    // 超时时间
    private int timeout;
    // 子线程
    private Thread thread;
    // 子线程是否停止标志
    public  bool isStop;

    /// <summary>
    /// 构造函数
    /// </summary>
    /// <param name="url">url地址</param>
    /// <param name="timeout">超时时间</param>
    /// <param name="callback">回调函数</param>
    public HTTPDownLoad(string _url, string _savePath, int _timeout)
    {
        savePath = _savePath;
        url = _url;
        timeout = _timeout;
        DownLoad();
    }
    /// <summary>
    /// 开启下载
    /// </summary>
    void DownLoad()
    {
        Status = 0;
        isStop = false;

        // 开启线程下载
        thread = new Thread(StartDownLoad);
        thread.IsBackground = true;
        thread.Start();
    }
    /// <summary>
    /// 开始下载
    /// </summary>
    private void StartDownLoad()
    {
    
        try
        {
            if (!Directory.Exists(savePath))
            {
                Directory.CreateDirectory(savePath);
            }
            string fileName = url.Split('/')[url.Split('/').Length - 1];
            string pathName = savePath + "/" + ErasePostfix(fileName) + postfix;
  
            // 构建文件流
            FileStream fs = new FileStream(pathName, FileMode.OpenOrCreate, FileAccess.Write);
            // 文件当前长度
            long fileLength = fs.Length;
            // 文件总长度
            TotalLength = GetDownLoadFileSize();
           // Debug.LogFormat("fileLen:{0}", TotalLength);
            if (fileLength < TotalLength)
            {
                // 没有下载完成
                fs.Seek(fileLength, SeekOrigin.Begin);
                // 发送请求开始下载
                HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
                request.AddRange((int)fileLength);
                request.Timeout = timeout;
                // 读取文件内容
                Stream stream = request.GetResponse().GetResponseStream();
                if (stream.CanTimeout)
                {
                    stream.ReadTimeout = timeout;
                }
                byte[] buff = new byte[4096];
                int len = -1;
                while ((len = stream.Read(buff, 0, buff.Length)) > 0)
                {
                    if (isStop)
                    {
                        break;
                    }
                    fs.Write(buff, 0, len);
                    fileLength += len;
                    Progress = fileLength * 1.0f / TotalLength;
                }
                stream.Close();
                stream.Dispose();
            }
            else
            {
                Progress = 1;
            }
            fs.Close();
            fs.Dispose();
            // 标记下载完成
            if (Progress == 1)
            {
                Status = 1;
         
                string filepathName = savePath + "/" + fileName;
                if (File.Exists(filepathName))//删除原来的
                    File.Delete(filepathName);
                File.Move(pathName, filepathName);
                Debug.Log("下载" + filepathName + "完毕");
            }
        }
        catch (Exception e)
        {
            Error = e.Message;
            Status = -1;
            Debug.Log(Error);
        }
    }
    /// <summary>
    /// 获取下载的文件大小
    /// </summary>
    /// <returns>文件大小</returns>
    public long GetDownLoadFileSize()
    {
        HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
        request.Method = "HEAD";
        request.Timeout = timeout;
        HttpWebResponse response = request.GetResponse() as HttpWebResponse;
        return response.ContentLength;
    }
    /// <summary>
    /// 停止下载
    /// </summary>
    public void Close()
    {
        isStop = true;
    }
    private string ErasePostfix(string filePath)
    {
        return filePath.Substring(0, filePath.LastIndexOf('.'));
    }
}

参考修改了其他人的代码，