java.lang. RuntimeException No Retrofit annotation found. (parameter #3)

Question

I'm trying to update this RetroFit + Otto tutorial, so my code updated is:

IWeather.java

RetroFit 2.+ doesn't allow to return void, so instead of void getWeather(...) I added Call<Weather> getWeather(...).

public interface IWeather {

    @GET("/{latitude},{longitude}")
    Call<Weather> getWeather(@Path("latitude") String latitude,
                             @Path("longitude") String longitude,
                             Callback<Weather> callback);
} 

ForecastClient.java

RetroFit 2.+ has changed his constructor, so the new ForecastClient has the next form. The IllegalArgumentException points to the weather.getWeather(...) method.

public class ForecastClient {

    private static final String BASE_URL = "https://api.darksky.net/forecast/";
    private static final String API_KEY = "******************";
    public static final String API_URL = BASE_URL + API_KEY + "/";

    private static ForecastClient mForecastClient;
    private static Retrofit mRetroAdapter;

    public static ForecastClient getClient() {
        if (mForecastClient == null) {
            mForecastClient = new ForecastClient();
        }
        return mForecastClient;
    }

    private ForecastClient() {
        mRetroAdapter = new Retrofit.Builder()
                .baseUrl(API_URL)
                .addConverterFactory(GsonConverterFactory.create())
                .client(new OkHttpClient())
                .build();
    }

    public void getWeather(String latitude, String longitude, Callback<Weather> callback) {
        IWeather weather = mRetroAdapter.create(IWeather.class);
        weather.getWeather(latitude, longitude, callback);
    }
}

ForecastManager.java

public class ForecastManager {

    private Context mContext;
    private Bus mBus;
    private ForecastClient sForecastClient;

    public ForecastManager(Context context, Bus bus) {
        this.mContext = context;
        this.mBus = bus;
        sForecastClient = ForecastClient.getClient();
    }

    @Subscribe
    public void onGetWeatherEvent(GetWeatherEvent getWeatherEvent) {
        String latitude = Double.toString(getWeatherEvent.getLatitude()).trim();
        String longitude = Double.toString(getWeatherEvent.getLongitude()).trim();

        Callback<Weather> callback = new Callback<Weather>() {
            @Override
            public void onResponse(Call<Weather> call, Response<Weather> response) {
                Log.d(ForecastManager.class.getSimpleName(), response.body().toString());
                mBus.post(new SendWeatherEvent(response.body()));
            }

            @Override
            public void onFailure(Call<Weather> call, Throwable t) {
                Log.e(ForecastManager.class.getSimpleName(), t.getMessage());
            }
        };

        sForecastClient.getWeather(latitude, longitude, callback);
    }
}

I'm receiving a No Retrofit annotation found and I guess the reason is something related with my callback, but it is a RetroFit callback, so I don't understand why the error.

The stacktrace points to the MainActivity, in particular to the Otto's method post() with a java.lang.RuntimeException: Could not dispatch event, caused by the error previously mentioned java.lang.IllegalArgumentException: No Retrofit annotation found. (parameter #3):

MainActivity.java

public class MainActivity extends AppCompatActivity {

    @BindView(R.id.activity_main_textView)
    TextView textView;
    @BindView(R.id.activity_main_button)
    Button button;

    private static final double LATITUDE = **.******;
    private static final double LONGITUDE = **.******;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ButterKnife.bind(this);
    }

    @OnClick(R.id.activity_main_button)
    public void onClick(View view) {
        BusProvider.getInstace().post(new GetWeatherEvent(LATITUDE, LONGITUDE));
    }

    @Subscribe
    public void onSendWeatherEvent(SendWeatherEvent sendWeatherEvent) {
        Weather weather = sendWeatherEvent.getWeather();
        Currently currently = weather.getCurrently();
        textView.setText(currently.getSummary());
    }

Any clue about where is the error or how should I handle the bus subscriptions, the callback, etcetera?

Answer 1

java.lang.IllegalArgumentException: No Retrofit annotation found. (parameter #3)

As the error says, the problem is that the third parameter of the getWeather method does not have an annotation. The Callback class is used for the Call#enqueue(Callback) method.

Simply change

sForecastClient.getWeather(latitude, longitude, callback)

to

sForecastClient.getWeather(latitude, longitude).enqueue(callback)

and remove the third parameter.

Answer 2

Try it and modify your retrofit version number to 2.6.0. The use of coroutines in Retrofit 2.6.0 can return a Response object directly. If await() is not needed, Retrofit will automatically call it. This is not applicable when the version is below 2.6.0.