android progress bar

hi am trying to add a progress bar to my activity, no clue how 开发者_如何学Goto do that. here is the scenario : my activity MESSAGING calls IMSERVICE.SENDFILE(), i pass the context from MESSAGING as argument to IMSERVICE.SENDFILE(). IMSERVICE.SENDFILE() calls SOCKETOPERATOR.SENDFILE(). i pass the same context to that too. SOCKETOPERATOR.SENDFILE() has a method that sends file and that looks like this :

public boolean sendFile(Context c,String path,String ip, int port)  {
        // TODO Auto-generated method stub


        try {


            String[] str = ip.split("\\.");

            byte[] IP = new byte[str.length];

            for (int i = 0; i < str.length; i++) {

                IP[i] = (byte) Integer.parseInt(str[i]);


            }
            Socket socket = getSocket(InetAddress.getByAddress(IP), port);
            if (socket == null) {
                Log.i("SO sendFILE","");

                return false;
            }
            Log.i("SocketOP", "sendFILE-1");
            File  f = new File(path);
            String filename=path.substring(path.lastIndexOf("/")+1);
            System.out.println("filename:"+filename); 
            fin.filename = "~"+filename;
            BufferedOutputStream out = new BufferedOutputStream( socket.getOutputStream() );

            FileInputStream fileIn = new FileInputStream(f);
            Log.i("SocketOP", "sendFILE-2");
            byte [] buffer  = new byte [(int)f.length()];
            System.out.println("SO sendFile f.length();" + f.length());
            int bytesRead =0;



            ProgressDialog pbarDialog =  new ProgressDialog(c); 
            pbarDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
            pbarDialog.setMessage("Loading...");
            pbarDialog.setCancelable(false);
             pbarDialog .setProgress(0);
             pbarDialog.show();
                while ((bytesRead = fileIn.read(buffer)) > 0) {
                                out.write(buffer, 0, buffer.length);
                  //get the previous value of progress bar 
                                int old_value = pbarDialog .getProgress();
                                //calculate how much did you read from the file
                                int new_read =(int)( ((float) f.length() / bytesRead)*100);
                                //add the new read to the old_value
                                int value = new_read+old_value;
                                pbarDialog.setProgress(value);  
                                Log.i("SocketOP", "sendFILE-3");

                  System.out.println("SO sendFile" + bytesRead +filename);
                            }
             pbarDialog.dismiss();







            out.flush();
            out.close();
            fileIn.close();






        } catch (IOException e) {
            return false;           
            //e.printStackTrace();
        }
        //  Toast.makeText(this, "Lvbvhhging...", Toast.LENGTH_SHORT).show();

        return true;     
    }

now as you can see i have a progressbar in it. i dont know how to make it show from my MESSAGING activity. also, im not sure if i have used the progressDilog correctly. could anyone help please?

You should do the processing in a background thread, while calling the progress dialog and other UI related stuff in the UI thread. Thats what AsyncTask was designed to do, read about it here: http://developer.android.com/reference/android/os/AsyncTask.html