Gson deserialization of List into realmList

Question

I\'m using retrofit with gson to deserialize my json into realm objects. This works very well for the most part. Trouble arises when dealing with

Rea

Answer 1

It is better to use JsonSerializer and JsonDeserializer rather than TypeAdapter for your RealmObject, because of 2 reasons:

1. They allow you to delegate (de)serialization for your RealmObject to the default Gson (de)serializer, which means you don't need to write the boilerplate yourself.

2. There's a weird bug in Gson 2.3.1 that might cause a StackOverflowError during deserialization (I tried the TypeAdapter approach myself and encountered this bug).

Here's how (replace Tag with your RealmObject class):

(NOTE that context.serialize and context.deserialize below are equivalent to gson.toJson and gson.fromJson, which means we don't need to parse the Tag class ourselves.)

Parser + serializer for RealmList:

public class TagRealmListConverter implements JsonSerializer>,
        JsonDeserializer> {

    @Override
    public JsonElement serialize(RealmList src, Type typeOfSrc,
                                 JsonSerializationContext context) {
        JsonArray ja = new JsonArray();
        for (Tag tag : src) {
            ja.add(context.serialize(tag));
        }
        return ja;
    }

    @Override
    public RealmList deserialize(JsonElement json, Type typeOfT,
                                      JsonDeserializationContext context)
            throws JsonParseException {
        RealmList tags = new RealmList<>();
        JsonArray ja = json.getAsJsonArray();
        for (JsonElement je : ja) {
            tags.add((Tag) context.deserialize(je, Tag.class));
        }
        return tags;
    }

}

Tag class:

@RealmClass
public class Tag extends RealmObject {
    private String value;

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }
}

Then register your converter class with Gson:

Gson gson = new GsonBuilder()
        .registerTypeAdapter(new TypeToken>() {}.getType(),
                new TagRealmListConverter())
        .create();