CODEWITHSUNDEEP
androidjsonrealm
steprobe
steprobe

Reputation: 1699

RealmObject to JSON

I am using Realm on Android and I have a RealmObject that I need to serialize to JSON and I am using GSON. The model looks like:

@RealmClass
public class User implements RealmModel {

    private String name;
    private RealmList<RealmString> memberships;

    ... (getters and setters omitted) 
}

When I read it from the server (using Retrofit and GSON), I write it to the database like:

realm.executeTransaction(realm1 -> realm1.copyToRealmOrUpdate(user));

If I then attempt to serialize the object, it works:

String userAsJson = getRealmSafeGson().toJson(test);

The Realm safe GSON is pretty much boilerplate from the docs. I put it here to avoid noise: https://gist.github.com/stephenroberts82/0e2cc93fa8983dd86b1f178b7c2c1a88

However, the next time I come and read the model from the database, all the values are null. This is fine, it is the documented lazy evaluation. So I try to do a copy, so GSON can work with it:

User copied = realm.copyFromRealm(user);
String userAsJson = getRealmSafeGson().toJson(copied);

But this time it doesn't work. It just hangs and eventually crashes due to out of memory.

Upvotes: 2

Views: 1599

Answers (2)

Vinay
Vinay

Reputation: 1899

Below code works for me:

try (Realm realm = Realm.getDefaultInstance()) {

    RealmResults<User> realmResult=realm.where(User.class).findAll();
    String reslutAsString=new Gson().toJson(realm.copyFromRealm(realmResult));
}

Upvotes: 2

EpicPandaForce
EpicPandaForce

Reputation: 81539

This is most likely because your User contains a cyclical reference, and copyFromRealm()'s default parameter says that it should try to copy it for as long as possible.

Try something like, copyFromRealm(user, 1) or copyFromRealm(user, 2).

Upvotes: 3

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