Domain objects using both Gson and SugarRecord, clashing over field name "id" in Retrofit call

Hey there,

I’m wondering if there’s a workaround for this little issue I’ve encountered in a class called User, which I deserialize from a JSON object using Gson, annotating like so:

public class User extends SugarRecord{
    private Long id; //used by Sugar

    @SerializeName("id") //used by Gson -- I can't change this field name
    private String userId;
}

Even though the variables are called totally different things and are different types in the definition of User, this addition of the Long id field with Sugar is causing Retrofit to throw an error, which says “com.package.User declares multiple JSON fields named id”.

Is there any possible workaround for this? Let me know if there’s anything else you might need to see, and thanks so much for any help you can offer!

[JonatanSalas]

@rachellejane @MangeshKadam What you have to do is not to extend from base class SugarRecord. Instead you should use the @Table annotation which gives to you the ability to declare by yourself a private Long id.

When declaring the private Long id, you have to use the keyword transient like this:

private transient Long id;

That mean that your id field won’t be serialized NEVER!

Example class:

@Table
public class User  {
    //If you declare as transient that field will be never serialized. 
    private transient Long id; 

    @SerializeName("id") 
    private String userId;
}

Hope this helps!

[JonatanSalas]

@rachellejane another thing that can be done when you have your model class extend from SugarRecord it’s to create an exclusion strategy for Gson.

public class SugarExclusionStrategy implements ExclusionStrategy {
    private Class<?> clazz;

    public SugarExclusionStrategy(Class<?> clazzToExclude) {
        this.clazz = clazzToExclude;
    }

    @Override
    public boolean shouldSkipClass(Class<?> clazz) {
        return false;
    }

    @Override
    public boolean shouldSkipField(FieldAttributes f) {
        return f.getDeclaringClass().equals(clazz) && f.getName().equals("id");
    }
}

And then add it when you create your Retrofit object like this:

final SugarExclusionStrategy strategy = new SugarExclusionStrategy(SugarRecord.class);

final Gson gson = new GsonBuilder()
                .addDeserializationExclusionStrategy(strategy)
                .addSerializationExclusionStrategy(strategy)
                .create();

final Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(baseUrl)
                .addConverterFactory(GsonConverterFactory.create(gson))
                .client(buildClient())
                .build();