Context context;
AlertDialog alertDialog;
boolean correct;
public BackgrroundWorker(Context context){
    this.context = context;
}
@Override
protected String doInBackground(String... params) {
    String type = params[0];
    String login_url = "random";
    String register_url = "random";
    if(type.equals("login")){
        try {
            String username = params[1];
            String password = params[2];
            URL url = new URL(login_url);
            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setDoOutput(true);
            httpURLConnection.setDoInput(true);
            OutputStream outputStream = httpURLConnection.getOutputStream();
            BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
            String post_data = URLEncoder.encode("username","UTF-8") + "=" +URLEncoder.encode(username,"UTF-8")+ "&"
                +URLEncoder.encode("password","UTF-8") + "=" +URLEncoder.encode(password,"UTF-8");
            bufferedWriter.write(post_data);
            bufferedWriter.flush();
            bufferedWriter.close();
            outputStream.close();
            InputStream inputStream = httpURLConnection.getInputStream();
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream,"iso-8859-1"));
            String result = "";
            String line = "";
            correct = false;
            while((line = bufferedReader.readLine()) != null){
                result += line;
            }
            bufferedReader.close();
            inputStream.close();
            httpURLConnection.disconnect();
            System.out.println(result);
            if (result.equalsIgnoreCase("login success"))
                correct=true;
            return result;
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
    return null;
}

@Override
protected void onPreExecute() {
    progressDialog = ProgressDialog.show(context, "Login",
            "Please wait for a while.", true);
    alertDialog = new AlertDialog.Builder(context).create();
    alertDialog.setTitle("Login status");



}

@Override
protected void onPostExecute(String result) {
    if(!result.equals("login success")) {
        alertDialog.setMessage(result);
        alertDialog.show();

    }
    progressDialog.dismiss();
}

@Override
protected void onProgressUpdate(Void... values) {
    super.onProgressUpdate(values);
}