My android studio app keeps crashing after using a background method to read a json from my fragment

Question

I am making an app using the Kitsu API. Here in this moment I have a fragment that allows me to search different anime using the api to get information such as name, synopsis, etc. After parsing the information I proceed to go back to my main activity to pass it to my new fragment, but it crashes the moment I initialize the method to go back to my main activity. My question is how do I use a fragment to read a JSON with a background class using ASYNCTASK and display it in a new fragment?

I have noticed that it jumps around a lot from my fragment, in an activity different from my main, to a class running in the background, to my main, to my fragment. Below are images of my code. Thank you very much.

Search fragment code, Main Activity search related methods, Search results background tasks, Search Results Fragment. To clarify It stops before I get to the string I labeled crashpoint and doesn't make it to the search results fragment. I felt like it would be handy to have that bit of code in there. Here is the error I get with my code when I run it.

Answer 1

You don't need to create a new fragment after reading JSON. Just to post an simple code that read JSON with async task:

package com.example.compsci_734t;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.URL;
import java.util.ArrayList;
import java.util.zip.GZIPInputStream;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.StatusLine;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.Activity;
import android.app.ListActivity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.ArrayAdapter;
import android.widget.ListView;



public class People extends Activity{

        ArrayList<String> items = new ArrayList<String>();
        static InputStream is = null;
        //private static String url = "";
        //private static String url = "http:...";
        private static String url = "http....";
        //URL requestUrl = new URL(url);
        JSONArray people = null;
        private static final String TAG_COURSES = "Courses";
        static JSONObject jObj = null;
        static String json = "";

        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.people);
            new MyTasks().execute();
        }


        private class MyTasks extends AsyncTask<URL, Void, JSONObject> {

            @Override
            protected JSONObject doInBackground(URL... urls) {
               // return loadJSON(url);
                try {
                    // defaultHttpClient
                    DefaultHttpClient httpClient = new DefaultHttpClient();
                    //HttpPost httpPost = new HttpPost(url);
                    HttpGet httpGet = new HttpGet(url);
                    HttpResponse httpResponse = httpClient.execute(httpGet);

                    HttpEntity httpEntity = httpResponse.getEntity();
                    is = httpEntity.getContent();

                } catch (UnsupportedEncodingException e) {
                    e.printStackTrace();
                } catch (ClientProtocolException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
              try {
                /*BufferedReader reader = new BufferedReader(new InputStreamReader(
                        is, "UTF-8"), 8);*/
                InputStream inputStream = is;
                GZIPInputStream input = new GZIPInputStream(inputStream);
                InputStreamReader reader = new InputStreamReader(input);
                BufferedReader in = new BufferedReader(reader);
                StringBuilder sb = new StringBuilder();
                String line = null;
                while ((line = in.readLine()) != null) {
                    sb.append(line);
                   //System.out.println(line);
                }
                is.close();
                json = sb.toString();
            } catch (Exception e) {
                Log.e("Buffer Error", "Error converting result " + e.toString());
            }

            // try parse the string to a JSON object

            try {

                JSONArray people = new JSONArray(json);
                //JSONArray people = new JSONArray(json);

                for (int i = 0; i < people.length(); i++) {
                    //System.out.println(courses.getJSONObject(i).toString());
                    JSONObject p = people.getJSONObject(i);

                    // Storing each json item in variable
                    String person_id = p.getString("someString1");


                    items.add(person_id);

                    /*Log.v("--", "People: \n" + "\n UPI: " + person_id);*/
                }


                //jObj = new JSONObject(json);
            } catch (JSONException e) {
                Log.e("JSON Parser", "Error parsing data " + e.toString());
            } 

            // return JSON String
            return jObj;
            }

            protected void onPostExecute(JSONObject json) {
                ListView myListView = (ListView)findViewById(R.id.peopleList);
                myListView.setAdapter(new ArrayAdapter(getApplicationContext(), android.R.layout.simple_list_item_1, items));
   }
}

The sample code was taken from this answer.