Volley-发出jsonarray发布请求

Question

我在参考几个谷歌搜索和stackoverflow问题后正在使用POST方法获取json数组的此类，但是我的代码给出了一个奇怪的错误Cannot Resolve Symbol POST

这是我的活动

public class fbuk extends Activity {

    // Movies json url
    private static final String url = "http://example.com/xyz.php";
    private ProgressDialog pDialog;
    private List<Movie> movieList = new ArrayList<Movie>();
    private ListView listView;
    private CustomListAdapter adapter;

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

        listView = (ListView) findViewById(R.id.listview);
        adapter = new CustomListAdapter(this, movieList);
        listView.setAdapter(adapter);

        pDialog = new ProgressDialog(this);
        // Showing progress dialog before making http request
        pDialog.setMessage("Loading...");
        pDialog.show();

        // changing action bar color

        // Creating volley request obj
        JsonArrayRequest movieReq = new PostJsonArrayRequest(Method.POST, url, null, 
            new Response.Listener<JSONArray>() {
                @Override
                public void onResponse(JSONArray response) {
                    Log.d(TAG, response.toString());
                    hidePDialog();

                    // Parsing json
                    for (int i = 0; i < response.length(); i++) {
                        try {

                            JSONObject obj = response.getJSONObject(i);
                            Movie movie = new Movie();
                            movie.setTitle(obj.getString("ttl"));
                            movie.setThumbnailUrl(obj.getString("img"));
                            movie.setRating(obj.getString("stts"));
                            movie.setYear(obj.getString("rel"));

                            movieList.add(movie);

                        } catch (JSONException e) {
                            e.printStackTrace();
                        }

                    }

                    // notifying list adapter about data changes
                    // so that it renders the list view with updated data
                    adapter.notifyDataSetChanged();
                }
            }, 
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    VolleyLog.d(TAG, "Error: " + error.getMessage());
                    hidePDialog();
                }
            });

        // Adding request to request queue
        AppController.getInstance().addToRequestQueue(movieReq);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        hidePDialog();
    }

    private void hidePDialog() {
        if (pDialog != null) {
            pDialog.dismiss();
            pDialog = null;
        }
    }
}


public class PostJsonArrayRequest extends JsonRequest<JSONArray> {

    /**
     * Creates a new request.
     * @param url URL to fetch the JSON from
     * @param listener Listener to receive the JSON response
     * @param errorListener Error listener, or null to ignore errors.
     */
    public PostJsonArrayRequest(String url, Response.Listener<JSONArray> listener, Response.ErrorListener errorListener) {
        super(Method.POST, url, null, listener, errorListener);
    }

    @Override
    protected Map<String, String> getParams() throws AuthFailureError {
        HashMap<String, String> params = new HashMap<String, String>();
        params.put("q", "ram");
        return params;
    }

    @Override
    protected Response<JSONArray> parseNetworkResponse(NetworkResponse response) {
        try {
            String jsonString =
                    new String(response.data,   HttpHeaderParser.parseCharset(response.headers));
            return Response.success(new JSONArray(jsonString),
                    HttpHeaderParser.parseCacheHeaders(response));
        } catch (UnsupportedEncodingException e) {
            return Response.error(new ParseError(e));
        } catch (JSONException je) {
            return Response.error(new ParseError(je));
        }
    }
}

我正在关注androidhive的教程

请指出哪里出了错

Answer 1

我已经这样做了（请参阅示例代码），请确保import com.android.volley.Request; 必须导入到您的活动类中，否则Request.Method.POST将不起作用，并且将出现“ 无法解析”

String url = "http://example.com/xyz.php";

    ErrorListener errorListener = new ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError errorResponce) 
        {

        }
    };

    Listener<JSONArray > jsonArrayListener = new Listener<JSONArray>() 
    {
        @Override
        public void onResponse(JSONArray response) {
            // TODO Auto-generated method stub

        }
    };


    PostJsonArrayRequest req = new PostJsonArrayRequest(Request.Method.POST, url , null, jsonArrayListener, errorListener);

并使用此类

 public class PostJsonArrayRequest extends JsonRequest<JSONArray> 
{

    public PostJsonArrayRequest(int method, String url, String requestBody,
            Listener<JSONArray> listener, ErrorListener errorListener) 
    {
        super(method, url, requestBody, listener, errorListener);
    }

    @Override
    protected Response<JSONArray> parseNetworkResponse(NetworkResponse response) 
    {
        try {
            String jsonString =
                    new String(response.data,   HttpHeaderParser.parseCharset(response.headers));
            return Response.success(new JSONArray(jsonString),
                    HttpHeaderParser.parseCacheHeaders(response));
        } catch (UnsupportedEncodingException e) {
            return Response.error(new ParseError(e));
        } catch (JSONException je) {
            return Response.error(new ParseError(je));
        }
    }

}

Answer 2

检查您的导入Method 。 它应该是

import com.android.volley.Request.Method

可能是您已将其导入为

import java.lang.reflect.Method;

Answer 3

采用

JsonArrayRequest movieReq = new PostJsonArrayRequest(Request.Method.POST,url,
        new Response.Listener<JSONArray>() {

并确保导入

import com.android.volley.Request.Method;

希望它能工作。