改造 2：我的 GET 请求出错

Question

我正在开发一个 Android 应用程序来显示评分最高的电影的海报。我想使用 Retrofit 2 来构建它。但是，我不断收到错误 'Service methods cannot return void'。这是堆栈跟踪：

FATAL EXCEPTION: main
Process: com.hfad.popularmovies, PID: 17921
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.hfad.popularmovies/com.hfad.popularmovies.MainActivity}: java.lang.IllegalArgumentException: Service methods cannot return void.
for method MoviesAPI.getFeedPopular
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
 at android.os.Looper.loop(Looper.java:148)
 at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.IllegalArgumentException: Service methods cannot return void.

我创建了一个 POJO，其中包含我需要的字段以及包含 get 请求的必要接口 =>

public interface MoviesAPI {
    @GET("/movie/top_rated?api_key=XXXXXXX")
    void getFeedTopRated(Callback <List<Movie>> response);

    @GET("/movie/popular?api_key=XXXXXXX")
    void getFeedPopular(Callback<List<Movie>> response);
}

这是应该通过 RecyclerView 显示海报的片段：

public class TopRatedFragment extends Fragment {
    private static final String ENDPOINT = "http://api.themoviedb.org/3/";
    private PosterAdapter adapter;
    private List<Movie> movieList;

    public TopRatedFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        RecyclerView recyclerView = (RecyclerView) inflater.inflate(R.layout.fragment_top_rated, container, false);
        adapter = new PosterAdapter(getActivity());
        recyclerView.setAdapter(adapter);
        GridLayoutManager layoutManager = new GridLayoutManager(getActivity(), 2);
        recyclerView.setLayoutManager(layoutManager);
        getTopRatedMovies();

        return recyclerView;
    }

    private void getTopRatedMovies() {
        Retrofit retrofit = new Retrofit.Builder()
                           .baseUrl(ENDPOINT)
                           .build();
        MoviesAPI api = retrofit.create(MoviesAPI.class);
        api.getFeedTopRated(new Callback<List<Movie>>() {
        @Override
        public void onResponse(Call<List<Movie>> call, Response<List<Movie>> response) {
            movieList = response.body();
            for (Movie movie : movieList) {
                movie.getPoster_path(); //I get the same error when I use 
            }
        }

        @Override
        public void onFailure(Call<List<Movie>> call, Throwable t) {
        }
    });
  }
}

如果我应该提供更多代码或背景信息，请告诉我。

Answer 1

您的接口方法需要 return 类型为

的对象

Call<Expected Result Object>

例如

@GET("/movie/top_rated?api_key=XXXXXXX")
Call<List<Movie>> getFeedTopRated();

并且在方法中需要编写如下函数：

api.getFeedTopRated().enque(new Callback<List<Movie>>() { /* */ });

改造 2：我的 GET 请求出错

Retrofit 2: error in my GET request

android

get-request

retrofit2