android 多线程下载 显示进度 速度

http://blog.csdn.net/JianTao_Yang/article/details/8433905

功能要求：从网络下载一APK应用，显示下载速度、进度，并安装应用。

运行效果图：

工程结构图：

很简单，就一个activity，一个更新UI的线程，一个下载线程加个文件处理类

主要代码：

 

 /**
  *多线程下载，UI更新类
  *@author young
  * */
 public class MultiThreadDownload extends Thread{
     private static final String TAG = "MultiThreadDownload";
     /**每一个线程需要下载的大小 */
     private int blockSize;
     /*** 线程数量<br> 默认为5个线程下载*/
     private int threadNum = 5;
     /*** 文件大小 */
     private int fileSize;
     /** * 已经下载多少 */
     private int downloadSize;
     /**文件的url,线程编号，文件名称*/
     private String UrlStr,ThreadNo,fileName;
     /***保存的路径*/
     private String savePath;
     /**下载的百分比*/
     private int downloadPercent = 0;
     /**下载的 平均速度*/
     private int downloadSpeed = 0;
     /**下载用的时间*/
     private int usedTime = 0;
     /**当前时间*/
     private long curTime;
     /**是否已经下载完成*/
     private boolean completed = false;
     private Handler handler ;
     /**
      * 下载的构造函数
      * @param url  请求下载的URL
      * @param handler   UI更新使用
      * @param savePath  保存文件的路径
      */
     public MultiThreadDownload(Handler handler,String url,String savePath)
     {
         this.handler = handler;
         this.UrlStr = url;
         this.savePath = savePath;
         Log.e(TAG, toString());
     }

     @Override
     public void run() {

         FileDownloadThread[] fds = new FileDownloadThread[threadNum];//设置线程数量
         try {
             URL url = new URL(UrlStr);
             URLConnection conn = url.openConnection();
             fileSize = conn.getContentLength();

             this.fileName = FileUtil.getFileName(UrlStr);
             //只创建一个文件，saveFile下载内容
             File saveFile = new File(savePath+"/"+fileName);
             Log.e(TAG, "文件一共："+fileSize+" savePath "+savePath+"  fileName  "+fileName);

             RandomAccessFile accessFile = new RandomAccessFile(saveFile,"rwd");
             //设置本地文件的长度和下载文件相同
             accessFile.setLength(fileSize);
             accessFile.close();
             //Handler更新UI，发送消息
             sendMsg(FileUtil.startDownloadMeg);
             //每块线程下载数据
             blockSize = ((fileSize%threadNum)==0)?(fileSize/threadNum):(fileSize/threadNum+1);
             Log.e(TAG, "每个线程分别下载 ："+blockSize);

             for (int i = 0; i < threadNum; i++) {
                 int curThreadEndPosition = (i+1)!=threadNum ? ((i+1)*blockSize-1) : fileSize;
                 FileDownloadThread fdt = new FileDownloadThread(url, saveFile, i*blockSize, curThreadEndPosition);
                 fdt.setName("thread"+i);
                 fdt.start();
                 fds[i]=fdt;
             }
             /**
              * 获取数据，更新UI，直到所有下载线程都下载完成。
              */
             boolean finished = false;
             //开始时间，放在循环外，求解的usedTime就是总时间
             long startTime = System.currentTimeMillis();
             while(!finished)
             {
                 downloadSize = 0;
                 finished = true;
                 for (int i = 0; i < fds.length; i++) {
                     downloadSize+= fds[i].getDownloadSize();
                     if(!fds[i].isFinished())
                     {
                         finished = false;
                     }
                 }
                 downloadPercent = (downloadSize*100)/fileSize;
                 curTime = System.currentTimeMillis();
                 System.out.println("curTime = "+curTime+" downloadSize = "+downloadSize+" usedTime "+(int) ((curTime-startTime)/1000));
                 usedTime = (int) ((curTime-startTime)/1000);

                 if(usedTime==0)usedTime = 1;
                 downloadSpeed = (downloadSize/usedTime)/1024;
                 sleep(1000);/*1秒钟刷新一次界面*/
                 sendMsg(FileUtil.updateDownloadMeg);
             }
             Log.e(TAG, "下载完成");
             completed = true;
             sendMsg(FileUtil.endDownloadMeg);
         } catch (Exception e) {
             Log.e(TAG, "multi file error  Exception  "+e.getMessage());
             e.printStackTrace();
         }
         super.run();
     }
     /**
      * 得到文件的大小
      * @return
      */
     public int getFileSize()
     {
         return this.fileSize;
     }
     /**
      * 得到已经下载的数量
      * @return
      */
     public int getDownloadSize()
     {
         return this.downloadSize;
     }
     /**
      * 获取下载百分比
      * @return
      */
     public int getDownloadPercent(){
         return this.downloadPercent;
     }
    /**
     * 获取下载速度
     * @return
     */
     public int getDownloadSpeed(){
         return this.downloadSpeed;
     }
     /**
      * 修改默认线程数
      * @param threadNum
      */
     public void setThreadNum(int threadNum){
         this.threadNum = threadNum;
     }
     /**
      * 分块下载完成的标志
      * @return
      */
     public boolean isCompleted(){
         return this.completed;
     }
     @Override
     public String toString() {
         return "MultiThreadDownload [threadNum=" + threadNum + ", fileSize="
                 + fileSize + ", UrlStr=" + UrlStr + ", ThreadNo=" + ThreadNo
                 + ", savePath=" + savePath + "]";
     }

     /**
      * 发送消息，用户提示
      * */
     private void sendMsg(int what)
     {
         Message msg = new Message();
         msg.what = what;
         handler.sendMessage(msg);
     }

 下载类：

 public class FileDownloadThread extends Thread{
     private static final String TAG = "FileDownloadThread";
     /**缓冲区 */
     private static final int BUFF_SIZE = 1024;
     /**需要下载的URL*/
     private URL url;
     /**缓存的FIle*/
     private File file;
     /**开始位置*/
     private int startPosition;
     /**结束位置*/
     private int endPosition;
     /**当前位置*/
     private int curPosition;
     /**完成*/
     private boolean finished = false;
     /**已经下载多少*/
     private int downloadSize = 0;

     /***
      * 分块文件下载，可以创建多线程模式
      * @param url   下载的URL
      * @param file  下载的文件
      * @param startPosition 开始位置
      * @param endPosition   结束位置
      */
     public FileDownloadThread(URL url, File file, int startPosition,
             int endPosition) {
         this.url = url;
         this.file = file;
         this.startPosition = startPosition;
         this.curPosition = startPosition;
         this.endPosition = endPosition;
         Log.e(TAG, toString());
     }

     @Override
     public void run() {
         BufferedInputStream bis = null;
         RandomAccessFile rAccessFile = null;
         byte[] buf = new byte[BUFF_SIZE];
         URLConnection conn = null;
         try {
             conn = url.openConnection();
             conn.setConnectTimeout(10000);//设置超时
             conn.setReadTimeout(10000);
             conn.setAllowUserInteraction(true);
                     System.out.println(this.getName()+" startPosition "+startPosition+" endPosition "+endPosition);
                     conn.setRequestProperty("Range", "bytes="+(startPosition)+"-"+endPosition);  //取剩余未下载的
                     rAccessFile = new RandomAccessFile(file,"rwd");//读写
                      //设置从什么位置开始写入数据
                     rAccessFile.seek(startPosition);
                     bis = new BufferedInputStream(conn.getInputStream(), BUFF_SIZE);
                     while(curPosition<endPosition)  //当前位置小于结束位置  继续下载
                     {
                         int len = bis.read(buf,0,BUFF_SIZE);
                         if(len==-1)   //下载完成
                         {
                             break;
                         }
                         rAccessFile.write(buf,0,len);
                         curPosition = curPosition +len;
                         if(curPosition > endPosition)
                         {   //如果下载多了，则减去多余部分
                             System.out.println("  curPosition > endPosition  !!!!");
                             int extraLen = curPosition-endPosition;
                             downloadSize += (len-extraLen+1);
                         }else{
                             downloadSize+=len;
                         }
                     }
                     this.finished = true;  //当前阶段下载完成
             Log.e(TAG, "当前"+this.getName()+"下载完成");
         } catch (Exception e) {
             Log.e(TAG, "download error Exception "+e.getMessage());
             e.printStackTrace();
         }finally{
             //关闭流
             FileUtil.closeInputStream(bis);
             try {
                 rAccessFile.close();
             } catch (IOException e) {
                 // TODO Auto-generated catch block
                 Log.e("AccessFile", "AccessFile IOException "+e.getMessage());
             }
         }
         super.run();
     }

     /**
      * 是否完成当前段下载完成
      * @return
      */
     public boolean isFinished() {
         return finished;
     }
     /**
      * 已经下载多少
      * @return
      */
     public int getDownloadSize() {
         return downloadSize;
     }

     @Override
     public String toString() {
         return "FileDownloadThread [url=" + url + ", file=" + file
                 + ", startPosition=" + startPosition + ", endPosition="
                 + endPosition + ", curPosition=" + curPosition + ", finished="
                 + finished + ", downloadSize=" + downloadSize + "]";
     }

这里面多线程下载是分段下载，创建保存一个文件(之前每个子线程都创建一个子文件，最后整合，发现文件整合有问题，安装失败，原因没找到)，子线程分别通过RandomAccessFile类进行写入操作。