Here I am getting parsed data from a URL and now I am trying to change the value of parse data to users only dynamically on an text view and my code is

package com.mokshya.jsontutorial;

import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.HashMap;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

import com.mokshya.jsontutorialhos.xmltest.R;

import android.app.AlertDialog;
import android.app.ListActivity;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.EditText;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.Toast;

public class Main extends ListActivity {

    EditText resultTxt;

    public double C_webuserDouble;
    public double C_cashDouble;
    public double C_transferDouble;

    public double S_webuserDouble;
    public double S_cashDouble;
    public double S_transferDouble;

    TextView cashTxtView;
    TextView webuserTxtView;
    TextView transferTxtView;
    TextView S_cashTxtView;
    TextView S_webuserTxtView;
    TextView S_transferTxtView;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.listplaceholder);
        cashTxtView = (TextView) findViewById(R.id.cashTxtView);
        webuserTxtView = (TextView) findViewById(R.id.webuserTxtView);
        transferTxtView = (TextView) findViewById(R.id.transferTxtView);

        S_cashTxtView = (TextView) findViewById(R.id.S_cashTxtView);
        S_webuserTxtView = (TextView) findViewById(R.id.S_webuserTxtView);
        S_transferTxtView = (TextView) findViewById(R.id.S_transferTxtView);

        ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();

        JSONObject json = JSONfunctions
                .getJSONfromURL("http://ldsclient.com/ftp/strtojson.php");

        try {

            JSONArray netfoxlimited = json.getJSONArray("netfoxlimited");

            for (inti = 0; i < netfoxlimited.length(); i++) {
                HashMap<String, String> map = new HashMap<String, String>();
                JSONObject e = netfoxlimited.getJSONObject(i);

                map.put("date", e.getString("date"));
                map.put("c_web", e.getString("c_web"));
                map.put("c_bank", e.getString("c_bank"));
                map.put("c_cash", e.getString("c_cash"));
                map.put("s_web", e.getString("s_web"));
                map.put("s_bank", e.getString("s_bank"));
                map.put("s_cash", e.getString("s_cash"));
                mylist.add(map);
            }
        } catch (JSONException e) {
            Log.e("log_tag", "Error parsing data " + e.toString());
        }

        ListAdapter adapter = new SimpleAdapter(this, mylist, R.layout.main,
                new String[] { "date", "c_web", "c_bank", "c_cash", "s_web",
                        "s_bank", "s_cash", }, new int[] { R.id.item_title,
                        R.id.webuserTxtView, R.id.transferTxtView,
                        R.id.cashTxtView, R.id.S_webuserTxtView,
                        R.id.S_transferTxtView, R.id.S_cashTxtView });

        setListAdapter(adapter);

        final ListView lv = getListView();
        lv.setTextFilterEnabled(true);
        lv.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                @SuppressWarnings("unchecked")
                HashMap<String, String> o = (HashMap<String, String>) lv
                        .getItemAtPosition(position);
                Toast.makeText(Main.this,
                        "ID '" + o.get("id") + "' was clicked.",
                        Toast.LENGTH_SHORT).show();

            }
        });
        resultTxt = (EditText) findViewById(R.id.editText1);
        resultTxt.setOnClickListener(new View.OnClickListener() {

            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                resultTxt.setText("");
            }
        });
        resultTxt.addTextChangedListener(new TextWatcher() {
            public void afterTextChanged(Editable arg0) {
                // TODO Auto-generated method stub

                String text;
                text = resultTxt.getText().toString();
                if (resultTxt.getText().length() > 5) {
                    calculateSum(C_webuserDouble, C_cashDouble,
                            C_transferDouble);
                    calculateSunrise(S_webuserDouble, S_cashDouble,
                            S_transferDouble);
                } else {

                }
            }

            public void beforeTextChanged(CharSequence s, int start, int count,
                    int after) {
                // TODO Auto-generated method stub

            }

            public void onTextChanged(CharSequence s, int start, int before,
                    int count) {
                // TODO Auto-generated method stub

            }

        });
    }

    private void calculateSum(Double webuserDouble, Double cashDouble,
            Double transferDouble) {

        String Qty;
        Qty = resultTxt.getText().toString();

        if (Qty.length() > 0) {
            double QtyValue = Double.parseDouble(Qty);
            double cashResult;
            double webuserResult;
            double transferResult;

            cashResult = cashDouble * QtyValue;
            webuserResult = webuserDouble * QtyValue;
            transferResult = transferDouble * QtyValue;

            DecimalFormat df = new DecimalFormat("#.##");
            String cashResultStr = df.format(cashResult);
            String webuserResultStr = df.format(webuserResult);
            String transferResultStr = df.format(transferResult);

            cashTxtView.setText(String.valueOf(cashResultStr));
            webuserTxtView.setText(String.valueOf(webuserResultStr));
            transferTxtView.setText(String.valueOf(transferResultStr));

            // cashTxtView.setFilters(new InputFilter[] {new
            // DecimalDigitsInputFilter(2)});

        }

        if (Qty.length() == 0) {
            cashTxtView.setText(String.valueOf(cashDouble));
            webuserTxtView.setText(String.valueOf(webuserDouble));
            transferTxtView.setText(String.valueOf(transferDouble));

        }

    }

    private void calculateSunrise(Double webuserDouble, Double cashDouble,
            Double transferDouble) {

        String Qty;
        Qty = resultTxt.getText().toString();

        if (Qty.length() > 0) {
            double QtyValue = Double.parseDouble(Qty);
            double cashResult;
            double webuserResult;
            double transferResult;

            cashResult = cashDouble * QtyValue;
            webuserResult = webuserDouble * QtyValue;
            transferResult = transferDouble * QtyValue;

            DecimalFormat df = new DecimalFormat("#.##");
            String cashResultStr = df.format(cashResult);
            String webuserResultStr = df.format(webuserResult);
            String transferResultStr = df.format(transferResult);

            S_cashTxtView.setText(String.valueOf(cashResultStr));
            S_webuserTxtView.setText(String.valueOf(webuserResultStr));
            S_transferTxtView.setText(String.valueOf(transferResultStr));
        }

        if (Qty.length() == 0) {
            S_cashTxtView.setText(String.valueOf(cashDouble));
            S_webuserTxtView.setText(String.valueOf(webuserDouble));
            S_transferTxtView.setText(String.valueOf(transferDouble));

        }

    }
}

and I am getting following error on logcat

08-28 15:04:12.839: E/AndroidRuntime(584): Uncaught handler: thread main exiting due to uncaught exception
08-28 15:04:12.848: E/AndroidRuntime(584): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mokshya.jsontutorialhos.xmltest/com.mokshya.jsontutorial.Main}: java.lang.NullPointerException
08-28 15:04:12.848: E/AndroidRuntime(584):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2401)
08-28 15:04:12.848: E/AndroidRuntime(584):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2417)
08-28 15:04:12.848: E/AndroidRuntime(584):  at android.app.ActivityThread.access$2100(ActivityThread.java:116)
08-28 15:04:12.848: E/AndroidRuntime(584):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794)
08-28 15:04:12.848: E/AndroidRuntime(584):  at android.os.Handler.dispatchMessage(Handler.java:99)
08-28 15:04:12.848: E/AndroidRuntime(584):  at android.os.Looper.loop(Looper.java:123)
08-28 15:04:12.848: E/AndroidRuntime(584):  at android.app.ActivityThread.main(ActivityThread.java:4203)
08-28 15:04:12.848: E/AndroidRuntime(584):  at java.lang.reflect.Method.invokeNative(Native Method)
08-28 15:04:12.848: E/AndroidRuntime(584):  at java.lang.reflect.Method.invoke(Method.java:521)
08-28 15:04:12.848: E/AndroidRuntime(584):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791)
08-28 15:04:12.848: E/AndroidRuntime(584):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:549)
08-28 15:04:12.848: E/AndroidRuntime(584):  at dalvik.system.NativeStart.main(Native Method)
08-28 15:04:12.848: E/AndroidRuntime(584): Caused by: java.lang.NullPointerException
08-28 15:04:12.848: E/AndroidRuntime(584):  at com.mokshya.jsontutorial.Main.onCreate(Main.java:111)
08-28 15:04:12.848: E/AndroidRuntime(584):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1123)
08-28 15:04:12.848: E/AndroidRuntime(584):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2364)