Android Volley请求将Recycler视图文本作为参数发布时出错

Question

I am creating a project using android recycler views to list the names of Indian states and districts. The Recycler view for state is working fine. However, when I try to post the retrieved text from recycler view to server using volley string request, it gives me error: "Value no of type java.lang.String cannot be converted to JSONObject." I am not able to figure out what is wrong. Can anyone please help me out with this? Iam new to Android and JSON. I have tried spinners and listviews as well to do this activity. It gives the same error when I try to send the text retrieved from adapter.

Method where I get the error:

private void loadDistricts() {

    RequestQueue queue = Volley.newRequestQueue(States.this);
    StringRequest request = new StringRequest(Request.Method.GET, url_districts,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {

                    try {
                        JSONObject obj = new JSONObject(response);
                        JSONArray statesArray = obj.getJSONArray("districts");

                        for(int i=0; i<statesArray.length(); i++) {
                            JSONObject stateObject = statesArray.getJSONObject(i);

                            String DtHindi = stateObject.getString("DtHindi");
                            String DTName = stateObject.getString("DTName");
                            String District11 = stateObject.getString("District11");

                            District districts = new District(DtHindi, DTName, District11);
                            dist_list.add(districts);
                            districtAdapter.notifyDataSetChanged();
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                        Toast.makeText(States.this, e.getMessage(), Toast.LENGTH_LONG).show();
                    }
                }
            }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            Toast.makeText(States.this, error.getMessage(), Toast.LENGTH_LONG).show();
        }
    }){
        @Override
        protected Map<String, String> getParams() throws AuthFailureError {
            Map<String, String> map = new HashMap<String, String>();
            map.put("state", state.getText().toString());
            return map;
        }
    };
    queue.add(request);
}

Entire code of the activity:

public class States extends AppCompatActivity {

EditText state, district;
RecyclerView state_recycler_view, district_recycler_view;
StateAdapter stateAdapter;
DistrictAdapter districtAdapter;
RecyclerView.LayoutManager stateLayoutManager, distLayoutManager;
List<State> state_list = new ArrayList<>();
List<District> dist_list = new ArrayList<>();

String getState, getDistrict;
String url_states = "http://subdomain.portalsamples.esy.es/states";
String url_districts = "http://subdomain.portalsamples.esy.es/districts";

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

    state = (EditText) findViewById(R.id.state);
    district = (EditText) findViewById(R.id.district);

    state_recycler_view = (RecyclerView) findViewById(R.id.state_recycler_view);
    stateAdapter = new StateAdapter(state_list);
    stateLayoutManager = new LinearLayoutManager(getApplicationContext());
    state_recycler_view.setLayoutManager(stateLayoutManager);

    district_recycler_view = (RecyclerView) findViewById(R.id.district_recycler_view);
    districtAdapter = new DistrictAdapter(dist_list);
    distLayoutManager = new LinearLayoutManager(getApplicationContext());
    district_recycler_view.setLayoutManager(distLayoutManager);

    state.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            loadStates();
            state_recycler_view.setAdapter(stateAdapter);
            state_recycler_view.setVisibility(View.VISIBLE);
        }
    });

    district.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            loadDistricts();
            district_recycler_view.setAdapter(districtAdapter);
            district_recycler_view.setVisibility(View.VISIBLE);
        }
    });

    state_recycler_view.addOnItemTouchListener(new RecyclerTouchListener(States.this, state_recycler_view, new RecyclerTouchListener.ClickListener() {
        @Override
        public void onClick(View view, int position) {
            state.setText(((TextView) state_recycler_view.findViewHolderForAdapterPosition(position).itemView.findViewById(R.id.STName)).getText().toString());
            state_list.clear();
            state_recycler_view.setVisibility(View.GONE);
        }

        @Override
        public void onLongClick(View view, int position) {
            district.setText(((TextView) district_recycler_view.findViewHolderForAdapterPosition(position).itemView.findViewById(R.id.DTName)).getText().toString());
            dist_list.clear();
            district_recycler_view.setVisibility(View.GONE);
        }
    }));
}

private void loadStates() {
    RequestQueue queue = Volley.newRequestQueue(States.this);
    StringRequest request = new StringRequest(Request.Method.GET, url_states,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {

                    try {
                        JSONObject obj = new JSONObject(response);
                        JSONArray statesArray = obj.getJSONArray("states");

                        for(int i=0; i<statesArray.length(); i++) {
                            JSONObject stateObject = statesArray.getJSONObject(i);

                            String StHindi = stateObject.getString("StHindi");
                            String STName = stateObject.getString("STName");
                            String State11 = stateObject.getString("State11");

                            State states = new State(StHindi, STName, State11);
                            state_list.add(states);
                            stateAdapter.notifyDataSetChanged();
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                        Toast.makeText(States.this, e.getMessage(), Toast.LENGTH_LONG).show();
                    }
                }
            }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            Toast.makeText(States.this, error.getMessage(), Toast.LENGTH_LONG).show();
        }
    });
    queue.add(request);
}

private void loadDistricts() {

    RequestQueue queue = Volley.newRequestQueue(States.this);
    StringRequest request = new StringRequest(Request.Method.GET, url_districts,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {

                    try {
                        JSONObject obj = new JSONObject(response);
                        JSONArray statesArray = obj.getJSONArray("districts");

                        for(int i=0; i<statesArray.length(); i++) {
                            JSONObject stateObject = statesArray.getJSONObject(i);

                            String DtHindi = stateObject.getString("DtHindi");
                            String DTName = stateObject.getString("DTName");
                            String District11 = stateObject.getString("District11");

                            District districts = new District(DtHindi, DTName, District11);
                            dist_list.add(districts);
                            districtAdapter.notifyDataSetChanged();
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                        Toast.makeText(States.this, e.getMessage(), Toast.LENGTH_LONG).show();
                    }
                }
            }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            Toast.makeText(States.this, error.getMessage(), Toast.LENGTH_LONG).show();
        }
    }){
        @Override
        protected Map<String, String> getParams() throws AuthFailureError {
            Map<String, String> map = new HashMap<String, String>();
            map.put("state", state.getText().toString());
            return map;
        }
    };
    queue.add(request);
}

Answer 1

Sorry... The problem was with the api. Unable to parse the response from server. Was using laravel to create my api. I have no idea why the response is always "empty input" when i use laravel to create the api. Using core php for api solved it. However my question is still there for laravel scripts. Why doesn't it accept input when posting data using volley request .....