Music Information

I'm making a music player and it was difficult to get information about the songs.
I'm using a ContentResolver and a Cursor to do the music searches in the device's memory. The information like name, title, artist and others and I can capture normal, since the Cursor itself returns this information, with the exception of the Album.
The problem is to capture the Genre (musical style). For this I use the MediaMetadataRetriever, however it is returning strange values.
In the case of the Album, the information is captured with the Cursor, but when the file does not have a saved album name, it returns the musical genre.
In the case of Genre, it returns numbers in some musical styles, for example: When it is a hip-hop it returns (5), when rap, returns (7) and so on.

The question is: How do I get this information correctly? Below is the code for reading songs

private void lerMusicas() {
    ContentResolver musicResolver = getContentResolver();
    Uri musicUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
    Cursor musicCursor = musicResolver.query(musicUri, null, null, null, null);

    if (musicCursor != null && musicCursor.moveToFirst()) {

        int titleColumn = musicCursor.getColumnIndex(MediaStore.Audio.Media.TITLE);
        int idColumn = musicCursor.getColumnIndex(MediaStore.Audio.Media._ID);
        int nameColumn = musicCursor.getColumnIndex(MediaStore.Audio.Media.DISPLAY_NAME);
        int artistColumn = musicCursor.getColumnIndex(MediaStore.Audio.Media.ARTIST);
        int albumColumn = musicCursor.getColumnIndex(MediaStore.Audio.Media.ALBUM);
        int folderColumn = musicCursor.getColumnIndex(MediaStore.Audio.Media.DATA);


        do {
            long thisId = musicCursor.getLong(idColumn);
            String thisTitle = musicCursor.getString(titleColumn);
            String thisArtist = musicCursor.getString(artistColumn);
            String thisAlbumArtist = "";
            String thisAlbum = musicCursor.getString(albumColumn);
            String thisName = musicCursor.getString(nameColumn);
            Uri thisUri = ContentUris.withAppendedId(musicUri, thisId);
            String thisGender = "";
            String thisFolder = musicCursor.getString(folderColumn);

            try {
                MediaMetadataRetriever retriever = new MediaMetadataRetriever();
                retriever.setDataSource(MainActivity.this, thisUri);
                if (retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_GENRE) != null)
                    thisGender = retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_GENRE);
                else thisGender = "<unknown>";
                if (retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_ALBUMARTIST) != null)
                    thisAlbumArtist = retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_ALBUMARTIST);
                else thisAlbumArtist = "<unknown>";

                retriever.release();
            } catch (RuntimeException ex) {
                // something went wrong with the file, ignore it and continue
            }

            todasMusicas.add(new Music(thisId, thisName, thisTitle, thisArtist, thisAlbumArtist, thisAlbum, thisGender, thisFolder, thisUri));
        }
        while (musicCursor.moveToNext());
    }
}

Ps: In a ViewPager, the information is displayed in a ListView, where only one information is displayed per Fragment.