Line -> JSONArray jArray=new JSONArray(result); giving nullpointer exception

Question

package com.example.fyptrialapp;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.HashMap;

import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONObject;

import android.app.Activity;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.StrictMode;
import android.text.Editable;
import android.text.TextWatcher;
import android.util.Log;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.AutoCompleteTextView;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Toast;

public class SearchByName extends Activity{

    HttpPost httppost;
    StringBuffer buffer;
    HttpResponse response;
    HttpClient httpclient;
    InputStream inputStream=null;
    Intent i;

    //public static final String recipes[]=new String[]{"Almond-Sheera","Bhel","Bread-Pizzas","Carrot-Pickle","Carrot-Relish"};
     String recipes[];

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.search_recipe);

        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);

        Button b2=(Button)findViewById(R.id.bSearchByName);

        try{

            httpclient = new DefaultHttpClient();
            httppost = new HttpPost("http://10.0.2.2/fypTrial2/searchByName.php");
            response = httpclient.execute(httppost);    // Execute HTTP Post Request
            inputStream = response.getEntity().getContent();
            String result=null;

            BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "iso-8859-1"), 8);
            StringBuilder sb = new StringBuilder();
            String line=null;
            while((line=reader.readLine())!= null){
                sb.append(line+"\n");
            }

            inputStream.close();
            result=sb.toString();

            JSONArray jArray=new JSONArray(result);// this statment gives error

            for(int i=0;i<jArray.length();i++){
                JSONObject json=jArray.getJSONObject(i);
                recipes[i]=json.getString("name");
            }
        }
        catch(Exception e){

            Log.e("log_tag3", "Error convering result"+e.toString());

        }

        ArrayAdapter<String> ac=new ArrayAdapter<String>(this,android.R.layout.simple_dropdown_item_1line,recipes);
            AutoCompleteTextView tv=(AutoCompleteTextView) findViewById(R.id.autoCompleteTextView2);
            tv.setAdapter(ac);
        b2.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
            Intent i=new Intent("com.example.practice.Search_Result");
            startActivity(i);
            }
        });     


    }   
}

ERROR

java.nullpointerexception. Error converting result variable.And the fatal main error

If i want to use ASnk task how should i write it.

Try to print `result` to see if it's `null`. – betteroutthanin Apr 05 '14 at 21:56 — betteroutthanin, Apr 05 '14 at 21:56

TmKVU · Answer 1 · 2014-04-06T08:12:44.983

0

You should indeed use AsyncTask for the networking part. Your app probably already crashes with a NetworkOnMainThread error follow this link for the usasge of AsyncTask.

But that besides, you are providing to little code to point to a reason for the NullPointerException. You should always check if an object is not null if it may occur it is.

try{
   //your code
}catch(NullPointerException ex){
   ex.printStackTrace();
}

edited Apr 06 '14 at 08:12

answered Apr 05 '14 at 22:00

TmKVU

2,910
2
16
30

code showing result is != null and still giving null pointerException – user3502270 Apr 06 '14 at 04:28
@user3502270 I have edited my code. This should catch the error, but you should probably find the source of why it is null – TmKVU Apr 06 '14 at 08:16

score 0 · Accepted Answer · edited May 23 '17 at 12:05

0

JSON syntax never starts as an array. It could be that it starts with { followed by [, but never straight to [. This is why trying to convert your results to JSONArray will not work. You should therefor try to get the object first, then the array elements.

JSONObject jo = new JSONObject(result);
JSONArray jArray = jo.getJSONArray("keyIdentifyer");

If you dont have the array key identifyer, you could try to iterate or get the first element. See this post answear on iterations when no keys are present.

edited May 23 '17 at 12:05

Community

1
1

answered Apr 06 '14 at 00:02

Olavz

139
1
6

thnx my problem solved. problem is in recipes[i]=json.getString("name"); line – user3502270 Apr 06 '14 at 07:16

Line -> JSONArray jArray=new JSONArray(result); giving nullpointer exception

2 Answers2

Linked