Retrofit 在onResponse方法外返回null？

Question

In the onResponse method, the logs returns a value but outside it, it returns null , maybe it does not wait for the response to finish, what could be the problem?

private  MovieResponse AsyncRequest() {
    Retrofit mRetrofit;
    MyWebService mService;
    mRetrofit = new Retrofit.Builder()
            .baseUrl(Constants.BASE_API_URL)
            .addConverterFactory(GsonConverterFactory.create(new Gson()))
            .build();
    mService = mRetrofit.create(MyWebService.class);
    mService.discoverPopularMovie(Constants.MOVIEDB_APIKEY).enqueue(new Callback<MovieResponse>() {
        @Override
        public void onResponse(@NonNull Call<MovieResponse> call, @NonNull Response<MovieResponse> response) {
            MovieResponse body = response.body();
            movieResponse = body ;
            Log.i(TAG, "onResponse: "+ " movieResponse "+ "HERE" +movieResponse);
        }
        @Override
        public void onFailure(Call<MovieResponse> call, Throwable t) {
            Toast.makeText(context, " failure", Toast.LENGTH_SHORT).show();
            t.printStackTrace();
        }
    });
    return movieResponse ;
}

Answer 1

The problem as you said, It doesn't wait for the response. What you need to know that enqueue() calls the request in another thread, so your code runs the request in a different thread than the return will calls.

If you need to wait for the response to return the response body using execute() instead of enqueue()

    try {
            Response<MovieResponse> = mService.discoverPopularMovie(Constants.MOVIEDB_APIKEY).execute();
        } catch (IOException e) {
            e.printStackTrace();
        }

note: This mustn't run in UI thread