如何下载文件(pdf, doc等)到sd卡和打开文件使用volley在android

Question

在我的android应用程序中，我需要下载一个文件到我的SD卡并通过意图查看它，我在我的应用程序中使用所有网络调用的截击库。想法。

Answer 1

class DownloadFileFromURL extends AsyncTask<String, String, String> {     
        /**
         * Before starting background thread
         * Show Progress Bar Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            showDialog(progress_bar_type);
        }
        /**
         * Downloading file in background thread
         * */
        @Override
        protected String doInBackground(String... f_url) {
            int count;
            try {
                URL url = new URL(f_url[0]);
                URLConnection conection = url.openConnection();
                conection.connect();
                // this will be useful so that you can show a tipical 0-100%           progress bar
                int lenghtOfFile = conection.getContentLength();
                // download the file
                InputStream input = new BufferedInputStream(url.openStream(), 8192);
                // Output stream
                OutputStream output = new FileOutputStream("/sdcard/downloadedfile.jpg");
                byte data[] = new byte[1024];
                long total = 0;
                while ((count = input.read(data)) != -1) {
                    total += count;
                    // publishing the progress....
                    // After this onProgressUpdate will be called
                    publishProgress(""+(int)((total*100)/lenghtOfFile));
                    // writing data to file
                    output.write(data, 0, count);
                }
                // flushing output
                output.flush();
                // closing streams
                output.close();
                input.close();
            } catch (Exception e) {
                Log.e("Error: ", e.getMessage());
            }
            return null;
        }
        /**
         * Updating progress bar
         * */
        protected void onProgressUpdate(String... progress) {
            // setting progress percentage
            pDialog.setProgress(Integer.parseInt(progress[0]));
       }
        /**
         * After completing background task
         * Dismiss the progress dialog
         * **/
        @Override
        protected void onPostExecute(String file_url) {
            // dismiss the dialog after the file was downloaded
            dismissDialog(progress_bar_type);
            // Displaying downloaded image into image view
            // Reading image path from sdcard
            String imagePath = Environment.getExternalStorageDirectory().toString() + "/downloadedfile.jpg";
            // setting downloaded into image view
        }
    }
}