使用RequestFuture.get（）时出现Android volley超时异常

Question

2.）AVD没有互联网问题（原因稍后解释）。

3.）与我的volley singleton类或请求队列无关（原因稍后解释）。

所以我想我在Volley/Request Future的用法上犯了某种错误。

public class BoxOffice extends android.support.v4.app.Fragment {
    private VolleySingleton volleySingleton;
    private RequestQueue requestQueue;
    private ImageLoader imageLoader;
    private ArrayList<MyMovie> movieList;
    private MyUriBuilder mBuilder;

    public BoxOffice() {
        // Required empty public constructor
        volleySingleton = VolleySingleton.getInstance();
        requestQueue = volleySingleton.getRequestQueue();
        mBuilder = new MyUriBuilder();
        movieList = new ArrayList<>();
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }
        StepA();
    }

    public void StepA() {
        String url = mBuilder.getURL("box");
        Log.d("RT", "StepA initiated - "+ url); // Url is perfect - works when copied in Safari.
        RequestFuture<JSONObject> futureA = RequestFuture.newFuture();
        JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, url, (String) null, futureA, futureA);
        requestQueue.add(request);

        try {
            JSONObject response = futureA.get(30, TimeUnit.SECONDS);
            Log.d("RT", "StepA - response received"); //Never reaches this step
            parseJsonFeed(response);
        } catch (InterruptedException e) {
            Log.e("RT", "StepA - InterruptedException - " + e);
            e.printStackTrace();
        } catch (ExecutionException e) {
            Log.e("RT", "StepA - ExecutionException - " + e);
            e.printStackTrace();
        } catch (TimeoutException e) {
            Log.e("RT", "StepA - TimeoutException - " + e);
            e.printStackTrace();
        }
        Log.d("RT", "StepA END");
    }

    public void parseJsonFeed(JSONObject response) {
        Log.d("RT", "StepA - parseFeed Begin");
        if (response == null || response.length() == 0) {
            return;
        }
        MyMovie currentMovie = null;
        DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");

        try {
            if (response.has("results")) {
                Log.d("RT", "StepA - results");
                JSONArray resultList = response.getJSONArray("results");
                for (int i = 0; i < 3; i++) {
                    Log.d("RT", "movie " + i);
                    JSONObject movieElement = resultList.getJSONObject(i);
                    if (movieElement.has("id") && movieElement.has("title")) {
                        currentMovie = new MyMovie();
                        currentMovie.setTmdb_id(movieElement.getString("id"));
                        currentMovie.setTitle(movieElement.getString("title"));
                        if (movieElement.has("release_date")) {
                            currentMovie.setReleaseDate(dateFormat.parse(movieElement.getString("release_date")));
                        } else {
                            currentMovie.setReleaseDate(dateFormat.parse("0000-00-00"));
                        }
                        movieList.add(i, currentMovie);
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        Log.d("RT", "StepA - parseFeed END");
    }
}

05-30 15:17:51.710  D/RT﹕ TL - Constructor Called
05-30 15:17:51.800  D/RT﹕ StepA initiated - https://api.themoviedb.org/3/movie/now_playing?api_key=##### (link works fine)
05-30 15:18:21.820  E/RT﹕ StepA - TimeoutException - java.util.concurrent.TimeoutException
05-30 15:18:21.820  D/RT﹕ StepA END

JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, mBuilder.getURL("box"), (String) null, new Response.Listener<JSONObject>() {
            @Override
            public void onResponse(JSONObject response) {
                parseJsonFeed(response);
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Toast.makeText(getActivity(), error.toString(), Toast.LENGTH_LONG).show();
            }
        });
        requestQueue.add(request);

Answer 1

遗憾的是，没有人能帮助回答这个问题，但我设法解决了这个问题，如下所示：

如果RequestFuture.get（）与UI线程位于同一线程上，则会发生超时。我已经更改了请求的机制，使得请求是在一个单独的异步线程（而不是UI线程）上完成的，并且响应也是在一个与请求分开的线程上接收的，如下所示：

private void StepA() {
        Log.d("RT", "StepA initiated");
        final CountDownLatch latchA = new CountDownLatch(1);

        Thread t = new Thread(new Runnable() {
            @Override
            public void run() {
                Log.d("RT", "Thread t Begins");
                ThreadA threadA = new ThreadA();
                try {
                    JSONObject jsonObject = threadA.execute().get(10, TimeUnit.SECONDS);
                    parseA(jsonObject);
                    latchA.countDown();
                    Log.d("RT", "Thread t Ends");
                } catch (InterruptedException e) {
                    e.printStackTrace();
                } catch (ExecutionException e) {
                    e.printStackTrace();
                } catch (TimeoutException e) {
                    e.printStackTrace();
                }
            }
        });
        t.start();
        try {
            latchA.await();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        Log.d("RT", "StepA END");
    }

下面是请求的异步任务代码：

protected class ThreadA extends AsyncTask<Void, Void, JSONObject> {
    final String url = mBuilder.getURL("box");

    public ThreadA() {
    }

    @Override
    protected JSONObject doInBackground(Void... params) {
        final RequestFuture<JSONObject> future = RequestFuture.newFuture();
        JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, url, (String) null, future, future);
        requestQueue.add(request);
        try {
            return future.get(10, TimeUnit.SECONDS);
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        } catch (TimeoutException e) {
            e.printStackTrace();
        }
        return null;
    }
}