CODEWITHSUNDEEP
androiddatabaserealmpersistenceone-to-many
IrApp
IrApp

Reputation: 1843

Realm one to many relationship not persisted

I'm trying to implement a Many-to-many relationship with Realm between Userand Chat objects. I'm following the oficial documentation. Here are my objects.

 public class User implements RealmModel {

  @PrimaryKey
  private String userId;
  private String name;
  private String phone;
  private String pictureURL;
  private String thumbnailURL;
  private String pushToken;
  private String status;
  private long lastOnlineMs;
  public RealmList<Chat> chats = new RealmList<>();

  public User() {}

}  

public class Chat implements RealmModel {

  @Required
  @PrimaryKey
  private String chatId;
  private long creationDateMs;
  private String creatorUserId;
  private String name;

  @LinkingObjects("chats")
  public final RealmResults<User> users = null;

  private int chatType;


  public Chat() {}
 }

Here is the code where I create the Chat object in the database and add the relation. The users have been correctly created before:

public void addChat(final Chat chat, final User creatorUser, final User opponentUser ) {
    realm.executeTransaction(realm -> {
        realm.copyToRealmOrUpdate(chat);

        creatorUser.chats.add(chat);
        opponentUser.chats.add(chat);
    });
}

After executing the code User and Chat objects are stored in database but chat list for users are empty.

I also use realm.beginTransaction that is just a same like executeTransaction, the difference just execute are thread safe.

I also use realm.insertOrUpdate(obj), but just have same result.

Upvotes: 1

Views: 583

Answers (1)

Maelig
Maelig

Reputation: 2096

copyToRealmOrUpdate from doc :

Updates an existing RealmObject that is identified by the same {@link io.realm.annotations.PrimaryKey} or a new copy if no existing object could be found

It does not update the RealmObject your are giving as parameter because it's not a managed object yet, so you need to retrieve the returned object that is managed to add it to your users.

public void addChat(final Chat chat, final User creatorUser, final User opponentUser ) {
    realm.executeTransaction(realm -> {
        Chat managedChat = realm.copyToRealmOrUpdate(chat);
        creatorUser.chats.add(managedChat);
        opponentUser.chats.add(managedChat);
    });
}

Upvotes: 1

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