文件上传下载进度条

进度条是一个很头疼的问题，当然弄明白了也很好理解，用起来也很方便，大都会涉及到两个，一个是圆形，另外一个则是长方形，一点一点推进的

对于圆形比较简单，先说说长方形的原理：

首先需要获取文件大小，在循环写的时候就进行加减乘法运算，哈哈，就这么简单！

给个例子吧：
 public class Android_X5_SOSO_9_9_2Activity extends Activity {
    /** Called when the activity is first created. */
    ProgressBar pb;
    TextView tv;
    int fileSize;
    int downLoadFileSize;
    String fileEx,fileNa,filename;
    private Handler handler = new Handler()
     {
     @Override
     public void handleMessage(Message msg)
     {//定义一个Handler，用于处理下载线程与UI间通讯

     if (!Thread.currentThread().isInterrupted())
     {
     switch (msg.what)
     {
     case 0:
     pb.setMax(fileSize);
     case 1:
     pb.setProgress(downLoadFileSize);
     int result = downLoadFileSize * 100 / fileSize;
     tv.setText(result + "%");
     break;
     case 2:
     Toast.makeText(Android_X5_SOSO_9_9_2Activity.this, "文件下载完成", 1000).show();
     break;

     case -1:
     String error = msg.getData().getString("error");
     Toast.makeText(Android_X5_SOSO_9_9_2Activity.this, error, 1000).show();
     break;
     }
     }
     super.handleMessage(msg);
     }
     };
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        pb=(ProgressBar)findViewById(R.id.down_pb);
        tv=(TextView)findViewById(R.id.tv);
        new Thread(){
            public void run(){
                try {
                    String localpath=Environment
                    .getExternalStorageDirectory()
                    .getAbsolutePath()+"/CXSOSO/"
                    +"20110901005.3gp";
                    down_file(localpath,"/sdcard/");
                    //下载文件，参数：第一个URL，第二个存放路径

                } catch (ClientProtocolException e) {
                    // TODO Auto-generated catch block

                    e.printStackTrace();
                } catch (IOException e) {
                    // TODO Auto-generated catch block

                    e.printStackTrace();
                }
            }
        }.start();


    }
    public void down_file(String url,String path) throws IOException{
        //下载函数

        filename=url.substring(url.lastIndexOf("/") + 1);
        //获取文件名

        /*URL myURL = new URL(url);
        URLConnection conn = myURL.openConnection();
        conn.connect();*/
        /*InputStream is = conn.getInputStream();
     this.fileSize = conn.getContentLength();//根据响应获取文件大小
*/
        File file = new File(url);
        DataInputStream is = new DataInputStream(new BufferedInputStream(new FileInputStream(file)));
        try {
            this.fileSize=read(file).length;
        } catch (Throwable e) {
            // TODO Auto-generated catch block

            e.printStackTrace();
        }
        if (this.fileSize <= 0) throw new RuntimeException("无法获知文件大小 ");
     if (is == null) throw new RuntimeException("stream is null");
     FileOutputStream fos = new FileOutputStream(path+filename);
     //把数据存入路径+文件名

     byte buf[] = new byte[1024];
     downLoadFileSize = 0;
     sendMsg(0);
     do
     {
         //循环读取

     int numread = is.read(buf);
     if (numread == -1)
     {
     break;
     }
     fos.write(buf, 0, numread);
     downLoadFileSize += numread;

     sendMsg(1);//更新进度条

     } while (true);
     sendMsg(2);//通知下载完成

     try
     {
     is.close();
     } catch (Exception ex)
     {
     Log.e("tag", "error: " + ex.getMessage(), ex);
     }

    }
    private void sendMsg(int flag)
    {
     Message msg = new Message();
     msg.what = flag;
     handler.sendMessage(msg);
    }
     public byte[] read(File myfile) throws Throwable{
            //定义输入流，将文件写入到fpath中

             DataInputStream inStream = new DataInputStream(new BufferedInputStream(new FileInputStream(myfile)));
         byte[] data = http://fxrz12.iteye.com/blog/readFile(inStream);

//         data.length;

         return data;
        }
     public static byte[] readFile(InputStream inStream) throws Throwable{
         int len = 0;
         byte[] buffer = new byte[1024];
         ByteArrayOutputStream outStream = new ByteArrayOutputStream();
         while((len = inStream.read(buffer))!=-1){
         outStream.write(buffer,0,len);
         }
         outStream.close();
         return outStream.toByteArray();
        }

}