Не удалось выполнить намерение после вставки данных в mysql

Question

Я вставляю свои данные в MySql, и данные вставляются успешно. Но я не могу до Intent к другому Activity после успешной операции.
Вот мой код:

public void registerfinish(View view) { 
    ... 
    new finalRegister().execute(); 
} 

class finalRegister extends AsyncTask<String, String, String> { 

    /** 
    * Before starting background thread Show Progress Dialog 
    * */ 
    @Override 
    protected void onPreExecute() { 
     super.onPreExecute(); 
     ... 
    } 

    /** 
    * getting All products from url 
    * */ 
    protected String doInBackground(String... args) { 

     List<NameValuePair> params = new ArrayList<NameValuePair>(); 
     ... 
     // getting JSON Object 
     // Note that create product url accepts POST method 
     JSONObject json = null ; 

     try { 
      json = jsonParser.makeHttpRequest(url, 
        "GET", params); 
     } catch (JSONException e) { 
      e.printStackTrace(); 
     } 



     // check for success tag 

     try { 
      // check log cat fro response 
      Log.d("Create Response", json.toString()); 
      success = json.getInt(TAG_SUCCESS); 
     } catch (JSONException e) { 
      e.printStackTrace(); 
     } 
     if (success == 1) { 
       // successfully created product 
       Intent i = new Intent(Register2ndStep.this, FinalScreen.class); 
       startActivity(i); 

       // closing this screen 
       //finish(); 
      } else { 
       ... 
      } 
     return null; 
    } 
    protected void onPostExecute(String file_url) { 
     // dismiss the dialog after getting all products 
     pDialog.dismiss(); 
     } 
    } 

} 

Logcat:

Caused by: java.lang.NullPointerException 
     at wolverine.example.com.btp_scientist.Register2ndStep$finalRegister.doInBackground(Register2ndStep.java:220) 
     at wolverine.example.com.btp_scientist.Register2ndStep$finalRegister.doInBackground(Register2ndStep.java:173) 

Register2ndStep.java:220: Log.d("Create Response", json.toString()) 
Register2ndStep.java:173: class finalRegister extends AsyncTask<String, String, String> 

Answer 1

Просто переместите пристальный код метода onPostExecute:

protected void onPostExecute(String file_url) { 
     Intent i = new Intent(Register2ndStep.this, FinalScreen.class); 
     startActivity(i); 
     pDialog.dismiss(); 
    }