from origin 'null' has been blocked by CORS policy

I want to upgrade the app from version 7 android sdk developed using phonegap to version 16 android sdk.

When you call PhoneGap.JSCallback, the following error occurs:

I/chromium: [INFO:CONSOLE(0)] "Access to XMLHttpRequest at 'http://127.0.0.1:42857/adbed140-2489-4bfd-94bf-319f79216d83' from origin 'null' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.", source: file:///android_asset/www/index.html (0)
I/chromium: [INFO:CONSOLE(711)] "JSCallback Error: Request failed.", source: file:///android_asset/www/js/phonegap.0.9.4.js (711)
D/NetworkManagementSocketTagger: tagSocket(64) with statsTag=0xffffffff, statsUid=-1
D/NetworkManagementSocketTagger: tagSocket(165) with statsTag=0xffffffff, statsUid=-1

I found out that the problem was cross domain and that I could filter it by adding ‘Access-Control-Allow-Orgin’ to the header, but I'm not sure how to add the relevant information to the Android app.

The following is the part of the source that is causing the error:

PhoneGap.JSCallback = function() {

var xmlhttp = new XMLHttpRequest();

// Callback function when XMLHttpRequest is ready
xmlhttp.onreadystatechange=function(){
    if(xmlhttp.readyState == 4){

        // If callback has JavaScript statement to execute
        if (xmlhttp.status == 200) {

            var msg = xmlhttp.responseText;
            setTimeout(function() {
                try {
                    var t = eval(msg);
                }
                catch (e) {
                    // If we're getting an error here, seeing the message will help in debugging
                    console.log("JSCallback: Message from Server: " + msg);
                    console.log("JSCallback Error: "+e);
                }
            }, 1);
            setTimeout(PhoneGap.JSCallback, 1);
        }

        // If callback ping (used to keep XHR request from timing out)
        else if (xmlhttp.status == 404) {
            setTimeout(PhoneGap.JSCallback, 10);
        }

        // If security error
        else if (xmlhttp.status == 403) {
            console.log("JSCallback Error: Invalid token.  Stopping callbacks.");
        }

        // If server is stopping
        else if (xmlhttp.status == 503) {
            console.log("JSCallback Error: Service unavailable.  Stopping callbacks.");
        }

        // If request wasn't GET
        else if (xmlhttp.status == 400) {
            console.log("JSCallback Error: Bad request.  Stopping callbacks.");
        }

        // If error, restart callback server
        else {
            console.log("JSCallback Error: Request failed.");
            CallbackServer.restartServer();
            PhoneGap.JSCallbackPort = null;
            PhoneGap.JSCallbackToken = null;
            setTimeout(PhoneGap.JSCallback, 100);
        }
    }
}

if (PhoneGap.JSCallbackPort == null) {
    PhoneGap.JSCallbackPort = CallbackServer.getPort();
}
if (PhoneGap.JSCallbackToken == null) {
    PhoneGap.JSCallbackToken = CallbackServer.getToken();
}

/** the part where an error is expected to occur. **/
xmlhttp.open("GET", "http://127.0.0.1:"+PhoneGap.JSCallbackPort+"/"+PhoneGap.JSCallbackToken , true);
xmlhttp.send();
};

There are also problems with the following sources:

package com.hello.world.plugin;

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

import android.content.Intent;
import android.net.Uri;
import android.os.Handler;
import android.util.Log;
import com.hello.world.R;
import com.hello.world.World;
import com.hello.world.push.PushService;

import com.phonegap.Device;
import com.phonegap.api.Plugin;
import com.phonegap.api.PluginResult;

public class NativeControls extends Plugin {
String callbackId;
/**
 * Executes the request and returns PluginResult.
 * 
 * @param action        The action to execute.
 * @param args          JSONArray of arguments for the plugin.
 * @param callbackId    The callback id used when calling back into JavaScript.
 * @return              A PluginResult object with a status and message.
 */
public PluginResult execute(String action, JSONArray args, String callbackId) {
    try {
        this.callbackId = callbackId;
        String deviceId = "";
        String serverUrl = "";
        String pushServerIp = "";
        String pushPort = "";
        if (action.equals("serverUrlInfo")) {
            serverUrl = this.ctx.getSharedPreferences(World.TAG, android.content.Context.MODE_PRIVATE).getString(World.SERVER_URL,"");
            if(serverUrl == null || "".equals(serverUrl)){
                Device device = new Device();
                device.setContext(this.ctx);
                deviceId = device.getDeviceId();
                Log.e("NativeControls serverUrlInfo.deviceID", deviceId);

                //default값 resource strings.xml read
                serverUrl = this.ctx.getResources().getString(R.string.server_url);
                pushServerIp = this.ctx.getResources().getString(R.string.push_server);
                pushPort = this.ctx.getResources().getString(R.string.push_port);

                // 서버 정보가 정상이라고 가정할 때, SharedPreferences에 SERVER_URL의 값이 없는 상태로 
                // WebView를 동작시에는 Toolbar에서 SERVER_URL이 빈 문자열로 반환될 수 있으므로, 기본값을 저장한다.
                this.ctx.getSharedPreferences(World.TAG, android.content.Context.MODE_PRIVATE).edit().putString(World.SERVER_URL, serverUrl).commit();

                this.ctx.getSharedPreferences(PushService.TAG, android.content.Context.MODE_PRIVATE).edit()
                    .putString(PushService.PREF_DEVICE_ID, deviceId)
                    .putString(PushService.MQTT_SVR_IP, pushServerIp)
                    .putInt(PushService.MQTT_SVR_PORT, Integer.parseInt(pushPort))
                    .commit();
            }
            String gwProtocol = "http", gwPort = "80";
            if ( serverUrl.startsWith("https://") ){
                gwProtocol = "https";
                gwPort = "443";
            }
            String gwDomain = serverUrl.substring(gwProtocol.length() + 3);
                   gwDomain = gwDomain.substring(0, gwDomain.indexOf("/"));

            if ( gwDomain.indexOf(":") > -1) {
                gwPort = gwDomain.substring(gwDomain.indexOf(":")+1);
                gwDomain = gwDomain.substring(0, gwDomain.indexOf(":"));
            }
            String gwContext = serverUrl.substring(serverUrl.lastIndexOf("/"));
            if ( gwContext.startsWith(gwDomain) && gwContext.indexOf("/") < 0) {
                gwContext = "";
            }

            JSONObject srvrInfo = new JSONObject();
            srvrInfo.put("serverUrl", serverUrl);
            srvrInfo.put("gwProtocol", gwProtocol);         // GW service Protocol (http , https)
            srvrInfo.put("gwDomain", gwDomain);             // GW service Domain or Ip
            srvrInfo.put("gwPort", gwPort);                 // GW service Port
            srvrInfo.put("gwContext", gwContext);           // GW service Context Name

            // The corresponding code returns new pluginResult (PluginResult.Status).JSON_EXCEPTION); returns to
            PluginResult r = new PluginResult(PluginResult.Status.OK, srvrInfo);
            return r;

        }
        //config
        else if (action.equals("serverUrlSave")) {
            saveConfig(args);
        }
        else if (action.equals("showToolBar")) {
            Handler mHandler = ((World)this.ctx).getToolbarHandler();
            mHandler.sendEmptyMessage(1);
        }
        else if (action.equals("hideToolBar")) {
            Handler mHandler = ((World)this.ctx).getToolbarHandler();
            mHandler.sendEmptyMessage(0);
        }
        else if (action.equals("openBrowser")) {
            String url = args.getString(0);     //URL
            final Intent intent = new Intent(Intent.ACTION_VIEW).setData(Uri.parse(url));
            this.ctx.startActivity(intent);
        }
        PluginResult r = new PluginResult(PluginResult.Status.OK);
        return r;
    } catch (JSONException e) {
        e.printStackTrace();

        // I don't know why the stacks are returned immediately without being created.
        return new PluginResult(PluginResult.Status.JSON_EXCEPTION);
    }
}
public void onActivityResult(int requestCode, int resultCode, Intent data){
    super.onActivityResult(requestCode, resultCode, data);
}
}