Unable to create call adapter for class example.Simple

Question

I am using retrofit 2.0.0-beta1 with SimpleXml. I want the retrieve a Simple (XML) resource from a REST service. Marshalling/Unmarshalling the Simple object with SimpleXML w

Answer 1

public interface SimpleService {

  @GET("/simple/{id}")
  Simple getSimple(@Path("id") String id);

}

Communication with the network is done with the separate thread so you should change your Simple with that.

public interface SimpleService {

  @GET("/simple/{id}")
  Call<Simple> getSimple(@Path("id") String id);

}

Answer 2

Short answer: return Call<Simple> in your service interface.

It looks like Retrofit 2.0 is trying to find a way of creating the proxy object for your service interface. It expects you to write this:

public interface SimpleService {
    @GET("/simple/{id}")
    Call<Simple> getSimple(@Path("id") String id);
}

However, it still wants to play nice and be flexible when you don't want to return a Call. To support this, it has the concept of a CallAdapter, which is supposed to know how to adapt a Call<Simple> into a Simple.

The use of RxJavaCallAdapterFactory is only useful if you are trying to return rx.Observable<Simple>.

The simplest solution is to return a Call as Retrofit expects. You could also write a CallAdapter.Factory if you really need it.