Android带进度条的文件上传示例（使用AsyncTask异步任务）

mTask = new MyTask(); mTask.execute(filePath, url); 

private class MyTask extends AsyncTask<String, Integer, String>{      @Override     protected void onPostExecute(String result) {       //最终结果的显示       mTvProgress.setText(result);       }      @Override     protected void onPreExecute() {       //开始前的准备工作       mTvProgress.setText("loading...");     }      @Override     protected void onProgressUpdate(Integer... values) {       //显示进度       mPgBar.setProgress(values[0]);       mTvProgress.setText("loading..." + values[0] + "%");     }      @Override     protected String doInBackground(String... params) {       //这里params[0]和params[1]是execute传入的两个参数       String filePath = params[0];       String uploadUrl = params[1];       //下面即手机端上传文件的代码       String end = "/r/n";       String twoHyphens = "--";       String boundary = "******";       try {         URL url = new URL(uploadUrl);         HttpURLConnection httpURLConnection = (HttpURLConnection) url             .openConnection();         httpURLConnection.setDoInput(true);         httpURLConnection.setDoOutput(true);         httpURLConnection.setUseCaches(false);         httpURLConnection.setRequestMethod("POST");         httpURLConnection.setConnectTimeout(6*1000);         httpURLConnection.setRequestProperty("Connection", "Keep-Alive");         httpURLConnection.setRequestProperty("Charset", "UTF-8");         httpURLConnection.setRequestProperty("Content-Type",             "multipart/form-data;boundary=" + boundary);          DataOutputStream dos = new DataOutputStream(httpURLConnection             .getOutputStream());         dos.writeBytes(twoHyphens + boundary + end);         dos             .writeBytes("Content-Disposition: form-data; name=/"file/"; filename=/""                 + filePath.substring(filePath.lastIndexOf("/") + 1)                 + "/"" + end);         dos.writeBytes(end);          //获取文件总大小         FileInputStream fis = new FileInputStream(filePath);         long total = fis.available();         byte[] buffer = new byte[8192]; // 8k         int count = 0;         int length = 0;         while ((count = fis.read(buffer)) != -1) {           dos.write(buffer, 0, count);           //获取进度，调用publishProgress()           length += count;           publishProgress((int) ((length / (float) total) * 100));           //这里是测试时为了演示进度,休眠500毫秒，正常应去掉           Thread.sleep(500);         }             fis.close();         dos.writeBytes(end);         dos.writeBytes(twoHyphens + boundary + twoHyphens + end);         dos.flush();          InputStream is = httpURLConnection.getInputStream();         InputStreamReader isr = new InputStreamReader(is, "utf-8");         BufferedReader br = new BufferedReader(isr);         @SuppressWarnings("unused")         String result = br.readLine();         dos.close();         is.close();         return "上传成功";     }catch (Exception e) {       e.printStackTrace();       return "上传失败";     }     }