Android Media Library

You can add new Media to the Android media library. Via an Intent you can tell the media application on the device that new content is available 

ContentValues values = new ContentValues(4);
long current = System.currentTimeMillis();
values.put(MediaStore.Audio.Media.TITLE, "audio" + audiofile.getName());
values.put(MediaStore.Audio.Media.DATE_ADDED, (int) (current / 1000));
values.put(MediaStore.Audio.Media.MIME_TYPE, "audio/3gpp");
values.put(MediaStore.Audio.Media.DATA, audiofile.getAbsolutePath());
ContentResolver contentResolver = getContentResolver();

Uri base = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
Uri newUri = contentResolver.insert(base, values);

// Notifiy the media application 
sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, newUri));