Android Retrofit Parameterized @Headers

Besides using @Header parameter, I'd rather use RequestInterceptor to update all your request without changing your interface. Using something like:

RestAdapter.Builder builder = new RestAdapter.Builder()    .setRequestInterceptor(new RequestInterceptor() {        @Override        public void intercept(RequestFacade request) {            request.addHeader("Accept", "application/json;versions=1");            if (isUserLoggedIn()) {                request.addHeader("Authorization", getToken());            }                            }    });

p/s : If you are using Retrofit2, you should use Interceptor instead of RequestInterceptor

Since RequestInterceptor is not longer available in Retrofit 2.0

Yes, you can pass them in runtime. As a matter of fact, pretty much exactly as you typed it out. This would be in your API interface class, named say SecretApiInterface.java

public interface SecretApiInterface {    @GET("/secret_things")    SecretThing.List getSecretThings(@Header("Authorization") String token)}

Then you pass the parameters to this interface from your request, something along those lines: (this file would be for example SecretThingRequest.java)

public class SecretThingRequest extends RetrofitSpiceRequest<SecretThing.List, SecretApiInteface>{    private String token;    public SecretThingRequest(String token) {        super(SecretThing.List.class, SecretApiInterface.class);        this.token = token;    }    @Override    public SecretThing.List loadDataFromNetwork() {        SecretApiInterface service = getService();        return service.getSecretThings(Somehow.Magically.getToken());    }}

Where Somehow.Magically.getToken() is a method call that returns a token, it is up to you where and how you define it.

You can of course have more than one @Header("Blah") String blah annotations in the interface implementation, as in your case!

I found it confusing too, the documentation clearly says it replaces the header, but it DOESN'T!
It is in fact added as with @Headers("hardcoded_string_of_liited_use") annotation

Hope this helps ;)

The accepted answer is for an older version of Retrofit. For future viewers the way to do this with Retrofit 2.0 is using a custom OkHttp client:

OkHttpClient httpClient = new OkHttpClient.Builder()  .addInterceptor(new Interceptor() {    @Override    public Response intercept(Chain chain) throws IOException {      Builder ongoing = chain.request().newBuilder();      ongoing.addHeader("Accept", "application/json;versions=1");      if (isUserLoggedIn()) {        ongoing.addHeader("Authorization", getToken());      }      return chain.proceed(ongoing.build());    }  })  .build();Retrofit retrofit = new Retrofit.Builder()  // ... extra config  .client(httpClient)  .build();

Hope it helps someone. :)