public class FileDownloadHelper {
  private static final String TAG = "FileDownloadHelper";
  /** 線程池 */
  private ThreadPool mPool = new ThreadPool();
  /** 開始下載 */
  public static final int MESSAGE_START = 0;
  /** 更新進度 */
  public static final int MESSAGE_PROGRESS = 1;
  /** 下載結(jié)束 */
  public static final int MESSAGE_STOP = 2;
  /** 下載出錯 */
  public static final int MESSAGE_ERROR = 3;
  /** 中途終止 */
  private volatile boolean mIsStop = false;
  private Handler mHandler;
  public volatile HashMap<String, String> mDownloadUrls = new HashMap<String, String>();

  public FileDownloadHelper(Handler handler) {
    if (handler == null)
      throw new IllegalArgumentException("handler不能為空!");

    this.mHandler = handler;
  }

  public void stopALl() {
    mIsStop = true;
    mPool.stop();
  }

  public void newDownloadFile(final String url) {
    newDownloadFile(url, Environment.getExternalStorageDirectory() + "/" + FileUtils.getUrlFileName(url));
  }

  /**
   * 下載一個新的文件
   * 
   * @param url
   * @param savePath
   */
  public void newDownloadFile(final String url, final String savePath) {
    if (mDownloadUrls.containsKey(url))
      return;
    else
      mDownloadUrls.put(url, savePath);
    mPool.start(new Runnable() {

      @Override
      public void run() {
        mHandler.sendMessage(mHandler.obtainMessage(MESSAGE_START, url));
        HttpClient client = new DefaultHttpClient();
        HttpGet get = new HttpGet(url);
        InputStream inputStream = null;
        FileOutputStream outputStream = null;
        try {
          HttpResponse response = client.execute(get);
          HttpEntity entity = response.getEntity();
          final int size = (int) entity.getContentLength();
          inputStream = entity.getContent();
          if (size > 0 && inputStream != null) {
            outputStream = new FileOutputStream(savePath);
            int ch = -1;
            byte[] buf = new byte[1024];
            //每秒更新一次進度
            new Timer().schedule(new TimerTask() {

              @Override
              public void run() {
                try {
                  FileInputStream fis = new FileInputStream(new File(savePath));
                  int downloadedSize = fis.available();
                  if (downloadedSize >= size)
                    cancel();
                  mHandler.sendMessage(mHandler.obtainMessage(MESSAGE_PROGRESS, downloadedSize, size, url));
                } catch (Exception e) {

                }
              }
            }, 50, 1000);

            while ((ch = inputStream.read(buf)) != -1 && !mIsStop) {
              outputStream.write(buf, 0, ch);
            }
            outputStream.flush();
          }
        } catch (Exception e) {
          Log.e(TAG, e.getMessage(), e);
          mHandler.sendMessage(mHandler.obtainMessage(MESSAGE_ERROR, url + ":" + e.getMessage()));
        } finally {
          try {
            if (outputStream != null)
              outputStream.close();
          } catch (IOException ex) {
          }
          try {
            if (inputStream != null)
              inputStream.close();
          } catch (IOException ex) {
          }
        }
        mDownloadUrls.remove(url);
        mHandler.sendMessage(mHandler.obtainMessage(MESSAGE_STOP, url));
      }
    });
  }
} 

 public Handler mDownloadHandler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
      PFile p;
      String url = msg.obj.toString();
      switch (msg.what) {
      case FileDownloadHelper.MESSAGE_START://開始下載
        p = new PFile();
        p.path = mParent.mFileDownload.mDownloadUrls.get(url);
        p.title = new File(p.path).getName();
        p.status = 0;
        p.file_size = 0;
        if (mDownloadAdapter == null) {
          mDownloadAdapter = new FileAdapter(getActivity(), new ArrayList<PFile>());
          mDownloadAdapter.add(p, url);
          mTempListView.setAdapter(mDownloadAdapter);
          mTempListView.setVisibility(View.VISIBLE);
        } else {
          mDownloadAdapter.add(p, url);
          mDownloadAdapter.notifyDataSetChanged();
        }
        break;
      case FileDownloadHelper.MESSAGE_PROGRESS://正在下載
        p = mDownloadAdapter.getItem(url);
        p.temp_file_size = msg.arg1;
        p.file_size = msg.arg2;
        int status = (int) ((msg.arg1 * 1.0 / msg.arg2) * 10);
        if (status > 10)
          status = 10;
        p.status = status;
        mDownloadAdapter.notifyDataSetChanged();
        break;
      case FileDownloadHelper.MESSAGE_STOP://下載結(jié)束
        p = mDownloadAdapter.getItem(url);
        FileBusiness.insertFile(getActivity(), p);
        break;
      case FileDownloadHelper.MESSAGE_ERROR:
        Toast.makeText(getActivity(), url, Toast.LENGTH_LONG).show();
        break;
      }
      super.handleMessage(msg);
    }
  }; 

        if (FileUtils.isVideoOrAudio(url)) {
          Dialog dialog = new AlertDialog.Builder(getActivity()).setIcon(android.R.drawable.btn_star).setTitle("播放/下載").setMessage(url).setPositiveButton("播放", new OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
              Intent intent = new Intent(getActivity(), VideoPlayerActivity.class);
              intent.putExtra("path", url);
              startActivity(intent);
            }
          }).setNeutralButton("下載", new OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
              MainFragmentActivity activity = (MainFragmentActivity) getActivity();
              activity.mFileDownload.newDownloadFile(url);
              Toast.makeText(getActivity(), "正在下載 .." + FileUtils.getUrlFileName(url) + " ，可從本地視頻查看進度！", Toast.LENGTH_LONG).show();
            }
          }).setNegativeButton("取消", null).create();
          dialog.show();
          return true;
        }