Json Data not showing up in spinner

Question

I am trying to retrieve JSON data from a server and then display that in a spinner, But the data is not showing up in the spinner, I am using volley to call to the server. How can i get the json data to show up in the spinner?

This is for testing pruposes, The spinner will retrieve catergories for upload location on my server then you select a category and then it uploads a file to that category also it will be using the selected categroy to link to uri.builder or something similiar to generate the URL for the location.

MainActivity.java

package com.smartpractice.myapplication;


import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.Toast;

import com.android.volley.DefaultRetryPolicy;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.RetryPolicy;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    Spinner spinner;
    String URL="https://www.smarhdhdh.co.za/app-categories.asp";
    ArrayList<String> categories;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        categories=new ArrayList<>();
        spinner=findViewById(R.id.country_Name);
        loadSpinnerData(URL);
        spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
                String country=   spinner.getItemAtPosition(spinner.getSelectedItemPosition()).toString();
                Toast.makeText(getApplicationContext(),country,Toast.LENGTH_LONG).show();
            }
            @Override
            public void onNothingSelected(AdapterView<?> adapterView) {
                // DO Nothing here
            }
        });
    }
    private void loadSpinnerData(String url) {
        RequestQueue requestQueue=Volley.newRequestQueue(getApplicationContext());
        StringRequest stringRequest=new StringRequest(Request.Method.GET, url, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                try{
                    JSONObject jsonObject=new JSONObject(response);
                    if(jsonObject.getInt("success")==1){
                        JSONArray jsonArray=jsonObject.getJSONArray("categories");

                        for(int i=0;i<jsonArray.length();i++){
                            JSONObject jsonObject1=jsonArray.getJSONObject(i);
                            String cat1=jsonObject1.getString("cat1");
                            categories.add(cat1);
                            JSONObject jsonObject2=jsonArray.getJSONObject(i);
                            String cat2=jsonObject2.getString("cat2");
                            categories.add(cat2);
                            JSONObject jsonObject3=jsonArray.getJSONObject(i);
                            String cat3=jsonObject3.getString("cat3");
                            categories.add(cat3);
                        }
                    }
                    spinner.setAdapter(new ArrayAdapter<>(MainActivity.this, android.R.layout.simple_spinner_dropdown_item, categories));
                }catch (JSONException e){e.printStackTrace();}
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                error.printStackTrace();
            }
        });
        int socketTimeout = 30000;
        RetryPolicy policy = new DefaultRetryPolicy(socketTimeout, DefaultRetryPolicy.DEFAULT_MAX_RETRIES, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT);
        stringRequest.setRetryPolicy(policy);
        requestQueue.add(stringRequest);
    }

Json data

ClientID = 5767
Username = [email protected]
Pwd = Smarthdhdhd@123

{"categories": { "cat1":"Ford", "cat2":"BMW", "cat3":"Fiat" }}

Answer 1

I assume the 'categories' field is not a JsonArray, it is a JsonObject instead. You should change your parsing code into

JSONObject categories = jsonObject.getJSONObject("categories");
 String cat1 = categories.getString("cat1");
 String cat2 = categories.getString("cat2");
 String cat3 = categories.getString("cat3");`