Handler handler = new Handler() { 
 
    @Override 
    public void handleMessage(Message msg) { 
      switch (msg.what) { 
      case 110://根据what值，执行UI更新操作 
        progressValue += msg.arg1; 
        sb.append(msg.obj); 
        mTextView.setText(sb.toString());//TextView显示读取内容 
        mDialog.setProgress(progressValue);//设置进度条当前值 
        if (progressValue == 100) {//判读是否读取结束 
           
          mDialog.dismiss(); 
          Toast.makeText(MainActivity.this, "读取完成！", Toast.LENGTH_SHORT).show(); 
        } 
         
        break; 
 
      } 
    } 
 
  }; 

File path = Environment.getExternalStorageDirectory();//获取sdcard根路径 
File file = new File(path + "/ProgressMonitor.txt");//读取根路径下的ProgressMonitor文件 

private void readFromFile(String path) { 
    FileInputStream fis; 
    DataInputStream dis; 
    try { 
      fis = new FileInputStream(path); 
      dis = new DataInputStream(fis); 
      byte b[] = new byte[10];// 每次读取10字节 
      while ((readed = dis.read(b)) != -1) { 
        Message msg = new Message(); 
        String str=new String(b,0,readed); 
        msg.obj=str; 
        msg.arg1 = readed; 
        msg.what = 110; 
        handler.sendMessage(msg); 
        try { 
          Thread.sleep(1000); 
        } catch (Exception e) { 
 
          e.printStackTrace(); 
        } 
 
      } 
 
    } catch (FileNotFoundException e) { 
 
      e.printStackTrace(); 
    } catch (IOException e) { 
      e.printStackTrace(); 
    }finally { 
      try { 
        dis.close(); 
        fis.close(); 
      } catch (IOException e) { 
        // TODO Auto-generated catch block 
        e.printStackTrace(); 
      } 
    } 
 
  } 

mDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);/进度条样式 
mDialog.setMax(100);//进度条最大值 
mDialog.setTitle("系统提示");//进度条标题 
mDialog.setIcon(R.drawable.ic_launcher);//进度条图标 
mDialog.setMessage("正在读取文件，请稍等。。。");//进度条提示信息 
 
mDialog.setProgress(progressValue);//进度条当前值 
mDialog.dismiss();//进度条消失 

private static final int STYLE_HORIZONTAL = 110; 
private static final int STYLE_SPINNER = 111; 
private void progressDialogStyle(int id) { 
    switch (id) { 
    case STYLE_SPINNER: 
      mDialog = new ProgressDialog(this, ProgressDialog.STYLE_SPINNER); 
      break; 
    case STYLE_HORIZONTAL: 
      mDialog = new ProgressDialog(this); 
      mDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL); 
      break; 
 
    default: 
      break; 
    } 
 
    mDialog.setMax(100); 
    mDialog.setTitle("系统提示"); 
    mDialog.setIcon(R.drawable.ic_launcher); 
    mDialog.setMessage("正在读取文件，请稍等。。。"); 
  }