JSON parsing from database

Question

I am trying to parse JSON from one of my json created but I am unable to parse it an throws a null pointer exception at the showdata() method. what is it that i am missing.I have checked with the array name and the php script. How do I implement it to solve the problem

parse activity

 import android.content.Intent;
    import android.support.v7.app.ActionBarActivity;
    import android.os.Bundle;
    import android.view.Menu;
    import android.view.MenuItem;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;

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


    public class ParseJSON extends ActionBarActivity implements View.OnClickListener {
        private String myJSONString;

        private static final String JSON_ARRAY="result";
        private static final String ID = "id";
        //private static final String NAME ="name";
        //private static final String PROFESSION= "profession";

        private JSONArray users = null;

        private int TRACK= 0;

        private EditText editTextId;
        private EditText editTextName;
        private EditText editTextProf;

        Button btnPrev;
        Button btnNext;

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

            Intent intent =getIntent();
            myJSONString = intent.getStringExtra(MainActivity.MY_JSON);


            editTextId = (EditText)findViewById(R.id.editTextID);
            //editTextName=(EditText)findViewById(R.id.editTextUsername);
            //editTextProf=(EditText)findViewById(R.id.editTextPassword);

            btnNext=(Button)findViewById(R.id.buttonNext);
            btnPrev=(Button)findViewById(R.id.buttonPrev);

            btnPrev.setOnClickListener(this);
            btnNext.setOnClickListener(this);

            extractJSON();
             showData();

        }



        private void extractJSON() {
            try {
                JSONObject jsonObject = new JSONObject();
                users = jsonObject.getJSONArray(JSON_ARRAY);

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

        }
            private void moveNext(){
           if(TRACK0){
                TRACK--;
            }
            showData();
        }

        private void showData(){
          try{
              JSONObject jsonObject= users.getJSONObject(TRACK);

              editTextId.setText(jsonObject.getString(ID));
          //    editTextName.setText(jsonObject.getString(NAME));
            //  editTextProf.setText(jsonObject.getString(PROFESSION));
          }catch(JSONException e){
              e.printStackTrace();
          }
        }
        @Override
        public boolean onCreateOptionsMenu(Menu menu) {
            // Inflate the menu; this adds items to the action bar if it is present.
            getMenuInflater().inflate(R.menu.menu_parse_json, menu);
            return true;
        }

        @Override
        public boolean onOptionsItemSelected(MenuItem item) {
            // Handle action bar item clicks here. The action bar will
            // automatically handle clicks on the Home/Up button, so long
            // as you specify a parent activity in AndroidManifest.xml.
            int id = item.getItemId();

            //noinspection SimplifiableIfStatement
            if (id == R.id.action_settings) {
                return true;
            }

            return super.onOptionsItemSelected(item);
        }

        @Override
        public void onClick(View view) {
          if(view==btnNext){
              moveNext();
          }
          else if (view==btnPrev)
              movePrev();
        }
    }

mainactivity

import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.text.method.ScrollingMovementMethod;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;


public class MainActivity extends ActionBarActivity implements View.OnClickListener {

    private TextView textviewJSON;
    private Button buttonGet;
    private Button buttonParse;


    public static final String MY_JSON="MY_JSON";
    public static final String JSON_URL="http://www.humanfox.com/capsule/dash.php";

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

        textviewJSON=(TextView)findViewById(R.id.textViewJSON);
        textviewJSON.setMovementMethod(new ScrollingMovementMethod());
        buttonGet=(Button)findViewById(R.id.buttonGet);
        buttonParse=(Button)findViewById(R.id.buttonParse);
        buttonGet.setOnClickListener(this);
        buttonParse.setOnClickListener(this);

    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }


        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onClick(View view) {
       if (view==buttonGet){
        getJSON(JSON_URL);

       }
       else if(view==buttonParse){
           showParseActivity();
       }
    }
    private void showParseActivity() {
        Intent intent = new Intent(this, ParseJSON.class);
        intent.putExtra(MY_JSON,textviewJSON.getText().toString());
        startActivity(intent);
    }

    private void getJSON(String url){
        class GetJSON extends AsyncTask{
                ProgressDialog loading;

            @Override
            protected void onPreExecute() {
                super.onPreExecute();
                loading= ProgressDialog.show(MainActivity.this, "Please Wait.....",null, true , true);
            }

            @Override
            protected String doInBackground(String... params) {

                String uri=params[0];
                BufferedReader bufferedReader= null;
                try{
                    URL url = new URL(uri);
                    HttpURLConnection con = (HttpURLConnection) url.openConnection();
                    StringBuilder sb = new StringBuilder();

                    bufferedReader= new BufferedReader(new InputStreamReader(con.getInputStream()));

                    String json;
                    while((json= bufferedReader.readLine())!=null){

                        sb.append(json+"
");

                    }
                    return sb.toString().trim();
                }catch(Exception e){
                    return null;
                }



            }

            @Override
            protected void onPostExecute(String s) {
                super.onPostExecute(s);
                loading.dismiss();

            }
        }

       GetJSON gj = new GetJSON();
       gj.execute(url);

    }


}

JSON parsing from database

Answers (1)

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