android application unfortunately stopped when running from real device

Question

hi I have made my first android application and it got a webservices to connect to mysql DB in my local PC using XAMPP I can run it perfectly from the Android emulator with no hassle but I need to run from my real device but I got the issue of the connection to the DB

so far I have changed the IP address in the file that contains the connection details for the web service and also the userfunction.java in eclipse (this one for the user reg. and login functions)

in the phone side , my PC uses LAN and my phone connects to the same connection using connectify wireless

but when I click on login button from my real device I got this in my logcat

05-18 12:19:40.600: E/SensorManager(13663): thread start
05-18 12:19:40.725: E/SpannableStringBuilder(13663): SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
05-18 12:19:40.725: E/SpannableStringBuilder(13663): SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
05-18 12:19:47.695: E/JSON Parser(13663): Error parsing data org.json.JSONException: End of input at character 0 of 
05-18 12:19:47.700: E/AndroidRuntime(13663): FATAL EXCEPTION: main
05-18 12:19:47.700: E/AndroidRuntime(13663): java.lang.NullPointerException
05-18 12:19:47.700: E/AndroidRuntime(13663):    at com.mohammed.watzIslam.LoginActivity$1.onClick(LoginActivity.java:62)
05-18 12:19:47.700: E/AndroidRuntime(13663):    at android.view.View.performClick(View.java:4211)
05-18 12:19:47.700: E/AndroidRuntime(13663):    at android.view.View$PerformClick.run(View.java:17267)
05-18 12:19:47.700: E/AndroidRuntime(13663):    at android.os.Handler.handleCallback(Handler.java:615)
05-18 12:19:47.700: E/AndroidRuntime(13663):    at android.os.Handler.dispatchMessage(Handler.java:92)
05-18 12:19:47.700: E/AndroidRuntime(13663):    at android.os.Looper.loop(Looper.java:137)
05-18 12:19:47.700: E/AndroidRuntime(13663):    at android.app.ActivityThread.main(ActivityThread.java:4898)
05-18 12:19:47.700: E/AndroidRuntime(13663):    at java.lang.reflect.Method.invokeNative(Native Method)
05-18 12:19:47.700: E/AndroidRuntime(13663):    at java.lang.reflect.Method.invoke(Method.java:511)
05-18 12:19:47.700: E/AndroidRuntime(13663):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)
05-18 12:19:47.700: E/AndroidRuntime(13663):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)
05-18 12:19:47.700: E/AndroidRuntime(13663):    at dalvik.system.NativeStart.main(Native Method)

this is the userfunction.java that keeps the location address of user reg. and login webserives

\
public class UserFunctions {

private JSONParser jsonParser;

private static String loginURL = "http://xxxx:port#/android_login_api/";
private static String registerURL = "http://xxxx:port#/android_login_api/";

private static String login_tag = "login";
private static String register_tag = "register";

// constructor
public UserFunctions(){
jsonParser = new JSONParser();
}

/**
* function make Login Request
* @param email
* @param password
* */
public JSONObject loginUser(String email, String password){
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("tag", login_tag));
params.add(new BasicNameValuePair("email", email));
params.add(new BasicNameValuePair("password", password));
JSONObject json = jsonParser.getJSONFromUrl(loginURL, params);
// return json
// Log.e("JSON", json.toString());
return json;
}

/**
* function make reg. Request
* @param name
* @param email
* @param password
* */
public JSONObject registerUser(String name, String password, String email){
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("tag", register_tag));
params.add(new BasicNameValuePair("name", name));
params.add(new BasicNameValuePair("email", email));
params.add(new BasicNameValuePair("password", password));



// getting JSON Object
JSONObject json = jsonParser.getJSONFromUrl(registerURL, params);
// return json
return json;
}

/**
* Function get Login status
* */
public boolean isUserLoggedIn(Context context){
DatabaseHandler db = new DatabaseHandler(context);
int count = db.getRowCount();
if(count > 0){
// user logged in
return true;
}
return false;
}

/**
* Function to logout user
* Reset Database
* */
public boolean logoutUser(Context context){
DatabaseHandler db = new DatabaseHandler(context);
db.resetTables();
return true;
}

}

can someone points out for any mistake or suggest me a solution

thanks

Answer 1

Add these packages:

import android.app.ProgressDialog;
import android.os.AsyncTask;

Declare json as class member field:

private JSONObject json;

Replace JSONObject json = jsonParser.getJSONFromUrl(loginURL, params); with this:

new AsyncTask<Void, Void, Void>() {
    ProgressDialog progressDialog;
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        progressDialog = new ProgressDialog(SplashActivity.this);
        progressDialog.setCancelable(false);
        progressDialog.setMessage("Loading, please wait...");
        progressDialog.show();
    }

    @Override
    protected Void doInBackground(Void... pms) {
        List<NameValuePair> params = new ArrayList<NameValuePair>();
        params.add(new BasicNameValuePair("tag", login_tag));
        params.add(new BasicNameValuePair("email", email));
        params.add(new BasicNameValuePair("password", password));
        json = jsonParser.getJSONFromUrl(loginURL, params);
        return null;
    }
    protected void onPostExecute(Void result) {
        if(progressDialog.isShowing()) {
            progressDialog.dismiss();
        }
        if(json != null) {
            Log.e("JSON", json.toString());
        }
        else {
            Log.e("JSON", "JSON is NULL");
        }
    };
}.execute();