Check if Content Resolver has value
<p>Following this <a href="http://stackoverflow.com/a/1287415/1072062">answer</a> on how to set a ringtone in an android activity, I'm using this code:</p>

<pre><code>File k = new File(path, "mysong.mp3"); // path is a file to /sdcard/media/ringtone

ContentValues values = new ContentValues();
values.put(MediaStore.MediaColumns.DATA, k.getAbsolutePath());
values.put(MediaStore.MediaColumns.TITLE, "My Song title");
values.put(MediaStore.MediaColumns.SIZE, 215454);
values.put(MediaStore.MediaColumns.MIME_TYPE, "audio/mp3");
values.put(MediaStore.Audio.Media.ARTIST, "Madonna");
values.put(MediaStore.Audio.Media.DURATION, 230);
values.put(MediaStore.Audio.Media.IS_RINGTONE, true);
values.put(MediaStore.Audio.Media.IS_NOTIFICATION, false);
values.put(MediaStore.Audio.Media.IS_ALARM, false);
values.put(MediaStore.Audio.Media.IS_MUSIC, false);

//Insert it into the database
Uri uri = MediaStore.Audio.Media.getContentUriForPath(k.getAbsolutePath());
Uri newUri = main.getContentResolver().insert(uri, values);

RingtoneManager.setActualDefaultRingtoneUri(
  myActivity,
  RingtoneManager.TYPE_RINGTONE,
  newUri
);
</code></pre>

<p>However, this creates a new entry in my Content Resolver every time I run my program. How can I check if a Uri is already present in the Content Resolver? I couldn't find anything in the documentations.</p>
