Does Retrofit support keypath on json parsing or something alike?

Question

For example i have json looks like:

{
    "data": [
        {
            "name": "one"
        },
        {
            "name": "two"
        }
    ]
}

For example i have object User with field name.

Is it possible write method which will parse data array to objects User?

something like

Call<List<User>> getUsers(@KeyPath("data"))

Now to do this, i need create a wrapper class something like

public class UsersWrapper {
    @SerializeName("data")
    public ArrayList<User> users;
}

and in service i do next

public interface Service {
    @GET("users")
    Call<UsersWrapper> getUsers()
}

But my all requests is just response with data but variable objects in array.

In this case i need create wrappers to any data requests. Pain :(

?

I don't understand the question. Your response object should be an array of `User` — gilgil28, Jan 27 '16 at 15:10
I tend to solve that by making the call return a `JsonObject`, then chain the call in a transformer that uses a gson instance to get the list from the `JsonObject`. And then I go after the API writer until they change it. — njzk2, Jan 27 '16 at 15:27

score 2 · Accepted Answer · edited May 23 '17 at 10:27

I'd do it this way:

Global class Wrapper<T> to parse the whole JSON

public class Wrapper<T> {
    public List<T> data;
}

And User to parse actual array;

public class User {
    public String name;
}

Then, the API interface:

@GET("/people")
Wrapper<User> getUsers();

And in DataSource class just do something like this:

@Override
public List<User> getUsers() {
    Wrapper<User> usersWrapper = myApiInterface.getUsers();
    return usersWrapper.data;
}

Upd1:
Another solution is to create custom JsonDeserializer (like described here) for List<User> type, register by registerTypeAdapter it with your custom Gson object and then you can deserialise your Json directly into List<User>. Though, this solution brings much more extra code and potential benefit is unclear for me.

That works. You can also generalize that for several API calls to `class Wrapper { public List data; }` provided that your responses all use the same `data` key. — njzk2, Jan 27 '16 at 15:29

Does Retrofit support keypath on json parsing or something alike?

1 Answers1