Android 试图获得歌曲的体裁，但失败了

我知道以前有人问过这个问题，但我还没有找到解决办法。 我正在尝试获取存储在设备存储器中的歌曲类型，并且我的应用程序下面的代码崩溃

public void getMusic() {
    ContentResolver contentResolver = getContentResolver();
    Uri songUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
    Cursor songCursor = contentResolver.query(songUri, null, null, null, null);
    if (songCursor != null && songCursor.moveToFirst()) {
        int songTitle = songCursor.getColumnIndex(MediaStore.Audio.Media.TITLE);
        int songArtist = songCursor.getColumnIndex(MediaStore.Audio.Media.ARTIST);
        int songAlbum = songCursor.getColumnIndex(MediaStore.Audio.Media.ALBUM);
        int songData = songCursor.getColumnIndex(MediaStore.Audio.Media.DATA);
        int songID = songCursor.getColumnIndex(MediaStore.Audio.Media._ID);
        MediaMetadataRetriever mr = new MediaMetadataRetriever();
        Uri trackUri = ContentUris.withAppendedId(
                android.provider.MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,songID);
        mr.setDataSource(getBaseContext(), trackUri);
        do {
            String currentID = songCursor.getString(songID);
            String currentTitle = songCursor.getString(songTitle);
            String currentArtist = songCursor.getString(songArtist);
            String currentAlbum = songCursor.getString(songAlbum);
            String currentData = songCursor.getString(songData);
            String currentGenre = mr.extractMetadata(MediaMetadataRetriever.METADATA_KEY_GENRE);
            songs.add(new Song(currentID, currentTitle, currentArtist, currentAlbum, currentGenre));
        } while (songCursor.moveToNext());
    }
}

我就是这样做的： 首先获取您的id:

           public String getGenreId(Context context, String genrename) {
    ContentResolver cr = context.getContentResolver();
    Uri uri = MediaStore.Audio.Genres.getContentUri("external");

    String genre_id = null;
    String genre = MediaStore.Audio.Genres.NAME;
    String id = MediaStore.Audio.Genres._ID;
    String[] strcriteria = {genrename};
    final String[] columns = {id, genre};
    Cursor cursor = null;
    try {
        cursor = cr.query(uri, columns, "name=?", strcriteria, null);
    } catch (Exception e) {
        e.printStackTrace();
    }
    if (cursor != null && cursor.moveToFirst()) {
        int genre_idCol = cursor
                .getColumnIndex(MediaStore.Audio.Genres._ID);
        genre_id = cursor.getString(genre_idCol);
        cursor.close();
    }
    return genre_id;
}

       public Cursor getgenre_TrackCursor(Context context, long genreID) {
    final String track_id = MediaStore.Audio.Genres.Members._ID;
    final String track_no = MediaStore.Audio.Genres.Members.TRACK;
    final String track_name = MediaStore.Audio.Genres.Members.TITLE;
    final String artist = MediaStore.Audio.Genres.Members.ARTIST;
    final String duration = MediaStore.Audio.Genres.Members.DURATION;
    final String album = MediaStore.Audio.Genres.Members.ALBUM;
    final String composer = MediaStore.Audio.Genres.Members.COMPOSER;
    final String year = MediaStore.Audio.Genres.Members.YEAR;
    final String path = MediaStore.Audio.Genres.Members.DATA;
    final ContentResolver resolve = context.getContentResolver();
    Uri uri = MediaStore.Audio.Genres.Members.getContentUri("external",
            genreID);
    final String[] columns = {track_id, track_no, artist, track_name,
            album, duration, year};
    return resolve.query(uri, columns, null, null, null);
}

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谢谢你的帮助，从我的问题到你的回答，我终于做到了