gistfile1.txt

            File dir = Environment.getExternalStoragePublicDirectory(
                    Environment.DIRECTORY_DOWNLOADS);

            if (!dir.exists() && !dir.mkdirs()) {
                dir = Environment.getExternalStorageDirectory();
                if (!dir.exists() && !dir.mkdirs()) {
                    throw new IOException(dir.getName() + " permissions denied");
                }
            }

            String name = "file_";
            
            SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd_HHmmss");
            name = name.concat(sdf.format(Calendar.getInstance().getTime())).concat(".bin");
            File dst = new File(dir, name);