如何将RealmObject添加到RealmList？

我试图像这样将SongRealm添加到SongListRealm：

public void insertSongToListWithKey(final int key, Song song){
    final SongRealm songRealm = mapper.toRealm(song);
    realm.beginTransaction();

    SongListRealm songListRealm = realm.where(SongListRealm.class).equalTo("key", key).findFirst();
    if(songListRealm!=null){
        songListRealm.getSongList().add(songRealm);
        realm.insertOrUpdate(songListRealm);
    }

    realm.commitTransaction();
}

之前：

名为“ A”的歌曲列表{名为“ 1”的歌曲，名为“ 2”的歌曲}

名为“ B”的歌曲清单{名为“ 14”的歌曲}

后：

名为“ A”的歌曲列表{名为“ 4”的歌曲，名为“ 4”的歌曲}

名为“ B”的歌曲列表{名为“ 4”的歌曲，名为“ 4”的歌曲}

我究竟做错了什么？祝你有个愉快的夜晚。预先谢谢你。

编辑

我要添加更多代码:)

SongListMapper（在SongList上更改SongListRealm的类）方法：

public SongList fromRealm(SongListRealm songListRealm){
    SongList songList = new SongList();
    ArrayList<Song> songArrayList = new ArrayList<>();
    RealmList<SongRealm> realmSongList = songListRealm.getSongList();
    for(SongRealm songRealm: realmSongList){
        songArrayList.add(songMapper.fromRealm(songRealm));
    }
    songList.setSongList(songArrayList);
    songList.setTitle(songListRealm.getName());
    songList.setKey(songListRealm.getKey());
    return songList;
}

SongMapper（用于在Song上更改SongRealm的类，反之亦然）：

public Song fromRealm(SongRealm songRealm){
    Song song = new Song();
    song.setArtist(songRealm.getArtist());
    song.setId(songRealm.getId());
    song.setPath(songRealm.getPath());
    song.setTitle(songRealm.getTitle());
    return song;
}

getAllTheSongLists（）方法：

public ArrayList<SongList> getAllTheSongLists() {
    ArrayList<SongList> songs = new ArrayList<>();
    SongListMapper mapper = new SongListMapper();
    RealmResults<SongListRealm> all = realm.where(SongListRealm.class).findAll().sort("key");
    for (SongListRealm songRealm : all) {
        if(songRealm.getKey()==idLastSongListValue)
            continue;
        songs.add(mapper.fromRealm(songRealm));
    }
    return songs;
}

我正在使用idLastSongListValue变量中的键保存上次使用的SongList-因此它不是由用户创建的SongList，并且我不想为用户显示它。

[解决了]

我必须使用新的主键创建新对象，并将Song对象的变量设置为创建的SongRealm对象，并从EpicPandaForce复制方法。希望对您有帮助。

public void insertSongToListWithKey(final int key, final Song song){
    realm.executeTransaction(new Realm.Transaction() {
        @Override
        public void execute(Realm r) {
            SongRealm songRealmNew = createSongRealm(song);
            SongListRealm songListRealm = realm.where(SongListRealm.class).equalTo("key", key).findFirst();
            if (songListRealm != null) {
                SongRealm savedSongRealm = realm.copyToRealmOrUpdate(songRealmNew);
                RealmList<SongRealm> songs = songListRealm.getSongList();
                if(!songs.contains(savedSongRealm)) {
                    songs.add(savedSongRealm);
                }
            }
        }
    });
}

private SongRealm createSongRealm(Song song){
    SongRealm songRealmNew = realm.createObject(SongRealm.class, generateIdForSong());
    songRealmNew.setId(song.getId());
    songRealmNew.setTitle(song.getTitle());
    songRealmNew.setPath(song.getPath());
    songRealmNew.setArtist(song.getArtist());
    return songRealmNew;
}

 private int generateIdForSong() {
    if(realm.where(SongRealm.class).max("key")==null)
        return 0;
    return realm.where(SongRealm.class).max("key").intValue() + 1;
 }