Custom Converter for Retrofit

Question

I am trying to use a custom converter for Retrofit

 RestAdapter.Builder builder = new RestAdapter.Builder()
                .setEndpoint(BuildConfig.BASE_SER         


        

Answer 1

I would do something like that:

public class StringList extends ArrayList {
    // Empty on purpose. The class is here only to be recognized by Gson
}

public class CitationMain {
    @SerializedName("field_name_here")
    StringList values;

    // Your other fields
}

Then when creating the RestAdapter:

public class StringListDeserializer implements JsonDeserializer {

    @Override
    public StringList deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext
            context) throws JsonParseException {
        StringList value = new StringList();
        if (json.isJsonArray()) {
            for (JsonElement element : json.getAsJsonArray()) {
                value.add(element.getAsString());
            }
        } else {
            value.add(json.getAsString());
        }
        return value;
    }
}

And then:

Gson gson = new GsonBuilder()
            .registerTypeAdapter(StringList.class, new StringListDeserializer())
            .create();

RestAdapter.Builder builder = new RestAdapter.Builder()
            //...
            .setConverter(new GsonConverter(gson));

It's not ideal, since the object is custom, but any other solution that I can think of right now is significantly more complex.

The deserializer here is registered specifically for the fields declared as StringList, and will handle the case of a single string as well as the case of a string array. Any other field type will use the default deserialization process.