AsyncTask() with HTTP log in not working

AsyncTask() with HTTP log in not working

The main aim is for me to connect my app with mysql database on the web.
Data is collected in JSON format.. and from the log cat the data seem to
be coming in but my app keeps on crashing after receiving the data.. This
is the error i got from the logCat
E/SpannableStringBuilder(3081): SPAN_EXCLUSIVE_EXCLUSIVE spans cannot
have a zero length
09-08 06:17:57.720: E/SpannableStringBuilder(3081):
SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
09-08 06:17:57.740: E/SpannableStringBuilder(3081):
SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
09-08 06:17:57.740: E/SpannableStringBuilder(3081):
SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
09-08 06:18:05.655: E/JSON(3081):
{"tag":"login","success":1,"error":0,"uid":"20","user":{"name":"mash","email":"mafulun4real@gmail.com","created_at":"28\/04\/13
06:27:"}}n
09-08 06:18:05.665: E/AndroidRuntime(3081): FATAL EXCEPTION: main
09-08 06:18:05.665: E/AndroidRuntime(3081): java.lang.NullPointerException
09-08 06:18:05.665: E/AndroidRuntime(3081): at
com.nairation.rss.LoginActivity.onPostExecute(LoginActivity.java:70)
09-08 06:18:05.665: E/AndroidRuntime(3081): at
com.nairation.rss.LoginActivity.onPostExecute(LoginActivity.java:1)
09-08 06:18:05.665: E/AndroidRuntime(3081): at
android.os.AsyncTask.finish(AsyncTask.java:631)
09-08 06:18:05.665: E/AndroidRuntime(3081): at
android.os.AsyncTask.access$600(AsyncTask.java:177)
09-08 06:18:05.665: E/AndroidRuntime(3081): at
android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644)
09-08 06:18:05.665: E/AndroidRuntime(3081): at
android.os.Handler.dispatchMessage(Handler.java:99)
09-08 06:18:05.665: E/AndroidRuntime(3081): at
android.os.Looper.loop(Looper.java:137)
09-08 06:18:05.665: E/AndroidRuntime(3081): at
android.app.ActivityThread.main(ActivityThread.java:5289)
09-08 06:18:05.665: E/AndroidRuntime(3081): at
java.lang.reflect.Method.invokeNative(Native Method)
09-08 06:18:05.665: E/AndroidRuntime(3081): at
java.lang.reflect.Method.invoke(Method.java:525)
09-08 06:18:05.665: E/AndroidRuntime(3081): at
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:739)
09-08 06:18:05.665: E/AndroidRuntime(3081): at
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:555)
09-08 06:18:05.665: E/AndroidRuntime(3081): at
dalvik.system.NativeStart.main(Native Method)
and this is the code
package com.nairation.rss;
import org.json.JSONException;
import org.json.JSONObject;
import com.nairation.library.DatabaseHandler;
import com.nairation.library.JSONParser;
import com.nairation.library.UserFunctions;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.widget.EditText;
public class LoginActivity extends AsyncTask<String, Void, Integer>{
private ProgressDialog progressDialog;
private int responsecode = 0;
private JSONParser jparser;
private String username;
private String password;
private Login activity;
public LoginActivity(ProgressDialog progressDialog){
this.progressDialog = progressDialog;
}
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
progressDialog.show();
}
@Override
protected Integer doInBackground(String... params) {
// TODO Auto-generated method stub
int count = params.length;
if(count == 2){
username = params[0];
password = params[1];
UserFunctions userfunc = new UserFunctions();
JSONObject jp = userfunc.loginUser(username, password);
try{
if(jp.getString("success") != null){
String res = jp.getString("success");
if(Integer.parseInt(res) == 1){
//Dat means the use is successfully logged in
DatabaseHandler db = new
DatabaseHandler(activity.getApplicationContext());
JSONObject juser = jp.getJSONObject("user");
userfunc.logoutUser(activity.getApplicationContext());
db.addUser(juser.getString("name"),
juser.getString("email"), jp.getString("uid"),
juser.getString("created_at"));
responsecode = 1;
}
}
} catch(NullPointerException e){
e.printStackTrace();
} catch(JSONException e){
e.printStackTrace();
}
}else{
responsecode = 0;
}
return responsecode;
}
@Override
protected void onPostExecute(Integer responsecode) {
// TODO Auto-generated method stub
//super.onPostExecute(responsecode);
EditText username = (EditText) activity.findViewById(R.id.loginname);
EditText pword = (EditText) activity.findViewById(R.id.loginpass);
if (responsecode == 1){
username.setText("");
pword.setText("");
progressDialog.dismiss();
}
if (responsecode == 0){
progressDialog.dismiss();
activity.showLoginError(responsecode);
}
}
}