Question

我正在构建一个从url下载pdf格式的书籍并将其存储到设备中的Android应用程序，所以我编写了这个代码来创建名为“Mypdf”的文件夹并在其下载后保存文件，但是当我运行设备中的应用程序我只找到了Mypdf文件但没有任何pdf书籍，在我使用的代码下面

  class DownloadFileAsync extends AsyncTask<String, String, String> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            showDialog(DIALOG_DOWNLOAD_PROGRESS);
        }

        @Override
        protected String doInBackground(String... aurl) {
            int count;

        try {

            File file = new File(Environment.getExternalStorageDirectory()+"/Mypdf");
            file.mkdir();

        URL url = new URL(aurl[0]);
        URLConnection conexion = url.openConnection();
        conexion.connect();

        int lenghtOfFile = conexion.getContentLength();
        Log.d("ANDRO_ASYNC", "Lenght of file: " + lenghtOfFile);

        InputStream input = new BufferedInputStream(url.openStream());
        OutputStream output = new FileOutputStream("Mypdf/ "+booknameText+ ".pdf");

        byte data[] = new byte[1024];

        long total = 0;

            while ((count = input.read(data)) != -1) {
                total += count;
                publishProgress(""+(int)((total*100)/lenghtOfFile));
                output.write(data, 0, count);
            }

            output.flush();
            output.close();
            input.close();
        } catch (Exception e) {}
        return null;

        }
        protected void onProgressUpdate(String... progress) {
             Log.d("ANDRO_ASYNC",progress[0]);
             mProgressDialog.setProgress(Integer.parseInt(progress[0]));
        }

        @Override
        protected void onPostExecute(String unused) {
            dismissDialog(DIALOG_DOWNLOAD_PROGRESS);

             Toast.makeText(getApplicationContext(), "The Book You downloaded had been saved into your SD Card " , Toast.LENGTH_LONG).show();
        }
    }

}

我使用了这个功能：

   OutputStream output = new FileOutputStream("/sdcard/ "+booknameText+ ".pdf");

但是很多时候很多设备都没有SD卡，所以文件不会被保存，所以请你能帮帮忙吗

在Android中保存pdf文件

0 个答案: