title: how to start a new activity after login success?
body: <p>i want to start a new activity after login success. that is when login goes correct a new activity should start automatically...i dont know where to mention startactivity. please help me with this, im a newbie to android.
  this is my code...</p>
  
  <pre><code>    public class BackgroundTask extends AsyncTask&lt;String,Void,String&gt; {
      AlertDialog alertDialog;
      Context ctx;
      BackgroundTask(Context ctx)
      {
          this.ctx =ctx;
      }
      @Override
      protected void onPreExecute() {
          alertDialog = new AlertDialog.Builder(ctx).create();
          alertDialog.setTitle("Login Information....");
      }
  
      @Override
      protected String doInBackground(String... params) {
          String reg_url = "";
          String login_url = "";
          String method = params[0];
          if (method.equals("register")) {
              String name = params[1];
              String user_name = params[2];
              String user_pass = params[3];
              try {
                  URL url = new URL(reg_url);
                  HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
                  httpURLConnection.setRequestMethod("POST");
                  httpURLConnection.setDoOutput(true);
  
                  //httpURLConnection.setDoInput(true);
                  OutputStream OS = httpURLConnection.getOutputStream();
                  BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(OS, "UTF-8"));
                  String data = URLEncoder.encode("user", "UTF-8") + "=" + URLEncoder.encode(name, "UTF-8") + "&amp;" +
                          URLEncoder.encode("user_name", "UTF-8") + "=" + URLEncoder.encode(user_name, "UTF-8") + "&amp;" +
                          URLEncoder.encode("user_pass", "UTF-8") + "=" + URLEncoder.encode(user_pass, "UTF-8");
                  bufferedWriter.write(data);
                  bufferedWriter.flush();
                  bufferedWriter.close();
                  OS.close();
                  InputStream IS = httpURLConnection.getInputStream();
                  IS.close();
                  //httpURLConnection.connect();
                  httpURLConnection.disconnect();
                  return "Registration Success...";
              } catch (MalformedURLException e) {
                  e.printStackTrace();
              } catch (IOException e) {
                  e.printStackTrace();
              }
          }
  
          else if(method.equals("login"))
          {
              String login_name = params[1];
              String login_pass = params[2];
              try {
                  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 data = URLEncoder.encode("login_name","UTF-8")+"="+URLEncoder.encode(login_name,"UTF-8")+"&amp;"+
                          URLEncoder.encode("login_pass","UTF-8")+"="+URLEncoder.encode(login_pass,"UTF-8");
                  bufferedWriter.write(data);
                  bufferedWriter.flush();
                  bufferedWriter.close();
                  outputStream.close();
  
                  InputStream inputStream = httpURLConnection.getInputStream();
                  BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream,"iso-8859-1"));
                  String response = "";
                  String line  = "";
                  while ((line = bufferedReader.readLine())!=null)
                  {
                      response+= line;
                  }
                  bufferedReader.close();
                  inputStream.close();
                  httpURLConnection.disconnect();
                  return response;
  
  
              } catch (MalformedURLException e) {
                  e.printStackTrace();
              } catch (IOException e) {
                  e.printStackTrace();
              }
  
  
          }
          return null;
      }
  
      @Override
      protected void onProgressUpdate(Void... values) {
          super.onProgressUpdate(values);
      }
  
      @Override
      protected void onPostExecute(String result) {
          if(result.equals("Registration Success..."))
          {
              Toast.makeText(ctx, result, Toast.LENGTH_LONG).show();
          }
          else
          {
              alertDialog.setMessage(result);
              alertDialog.show();
          }
  
      }
  }
  </code></pre>