Asynk Задание вызова в цикле, не возвращающее значение

Question

Я пытаюсь создать приложение, которое обновит погоду нескольких городов. Каждая строка будет иметь разную временную температуру, поэтому я использую AsynkTask. Но я не могу обновить интерфейс после получения ответа от API.

Мой Основная деятельность

public class MainActivity extends Activity { 
    LinearLayout depart_arrivals_details; 
    LayoutInflater inflater; 
    TextView depart_time, 
    depart_airport_city, depart_airport, arrival_time, 
    arrival_airport_city, arrival_airport, pnr_number,temprature,humidity; 
    ImageView flight_depart_image; 
    public static String url = ""; 
    WeatherResponse response; 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     depart_arrivals_details = (LinearLayout) findViewById(R.id.depart_arrivals_details); 
     inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
     setSectorData(); 
    } 

    void setSectorData() { 
     for (int i = 0; i < 1; i++) { 
      inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
      RelativeLayout layout = (RelativeLayout) inflater.inflate(
        R.layout.sector_details, depart_arrivals_details, false); 
      depart_time = (TextView)layout.findViewById(R.id.depart_time); 
      depart_airport_city = (TextView)layout.findViewById(R.id.depart_airport_city); 
      temprature = (TextView)layout.findViewById(R.id.temprature); 
      humidity = (TextView)layout.findViewById(R.id.humidity); 
      flight_depart_image = (ImageView)layout.findViewById(R.id.flight_depart_image); 
      WeatherResponse responseUpdate = requestWeatherUpdate("DEL"); 

     depart_time.setText("20:45"); 
     depart_airport_city.setText("Mumbai"); 
     /* 
     * This part will be updated when we will se the request and get the response 
     * then we have to set the temp and humidity for each city that we have recived 
     * */ 
     temprature.setText(responseUpdate.getTempInC()+(char) 0x00B0);//Here it is showing null pointer exception after that the respone is coming from the server .So can we do this 
     humidity.setText(responseUpdate.getHumidity()); 

      flight_depart_image.setImageResource(R.drawable.f1); 

      depart_arrivals_details.addView(layout, i); 
     } 
    } 

    /* 
    * Here the location will be dynamic and have to send the request for all the location i have 
    * */ 
    private WeatherResponse requestWeatherUpdate(String location) { 
     url = "http://api.worldweatheronline.com/free/v1/weather.ashx?&format=xml&num_of_days=2&key=uysakmq923nbd5y549yz3aaw&q=" 
       + location; 
     Log.d("URL for Weather Upadate", url); 
     WeatherUpdateAsyncTask weatherReq = new WeatherUpdateAsyncTask(new CallBack() { 
      @Override 
      public void run(Object result) { 
       try { 
        String AppResponse = (String) result; 
        response = ParseWeatherResponseXML 
          .parseMyTripXML(AppResponse); 
       } catch (Exception e) { 
        Log.e("TAG Exception Occured", 
          "Exception is " + e.getMessage()); 
       } 
      } 
     }); 
     weatherReq.execute(url); 
     return response; 

    } 

Это мой requestWeatherUpdate

private WeatherResponse requestWeatherUpdate(String location) { 
     url = "" 
       + location; 
     Log.d("URL for Weather Upadate", url); 
     WeatherUpdateAsyncTask weatherReq = new WeatherUpdateAsyncTask(new CallBack() { 
      @Override 
      public void run(Object result) { 
       try { 
        String AppResponse = (String) result; 
        response = ParseWeatherResponseXML 
          .parseMyTripXML(AppResponse); 
       } catch (Exception e) { 
        Log.e("TAG Exception Occured", 
          "Exception is " + e.getMessage()); 
       } 
      } 
     }); 
     weatherReq.execute(url); 
     return response; 

    } 

И если я пытаюсь установить значение, которое я полученый бросает Исключение нулевого указателя

Answer 1

Попробуйте

Первый в для Loop

depart_arrivals_details.removeAllViews(); 
for (int i = 0; i < 2; i++) { 
      requestWeatherUpdate("BLR"); 
      } 

Функция WeatherResponse

private WeatherResponse requestWeatherUpdate(String location) { 
     url = "" 
       + location; 
     Log.d("URL for Weather Upadate", url); 
     WeatherUpdateAsyncTask weatherReq = new WeatherUpdateAsyncTask(); 
     String weatherRequestResponse=""; 
     try { 
      weatherRequestResponse=weatherReq.execute(url).get(); 
      parsedWeatherResponse = ParseWeatherResponseXML 
        .parseMyTripXML(weatherRequestResponse); 
     } catch (InterruptedException e) { 

      e.printStackTrace(); 
     } catch (ExecutionException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } catch (ParserConfigurationException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } catch (SAXException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } catch (IOException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 
     return parsedWeatherResponse; 

    } 

А потом AsynkTask

public class WeatherUpdateAsyncTask extends AsyncTask<String, Void, String> { 
    Context context; 
    CallBack callBack; 

    @Override 
    protected String doInBackground(String... arg0) { 
     String responseString = ""; 
     HttpClient client = null; 
     try { 
      client = new DefaultHttpClient(); 
      HttpGet get = new HttpGet(arg0[0]); 
      client.getParams().setParameter("http.socket.timeout", 6000); 
      client.getParams().setParameter("http.connection.timeout", 6000); 
      HttpResponse responseGet = client.execute(get); 
      HttpEntity resEntityGet = responseGet.getEntity(); 
      if (resEntityGet != null) { 
       responseString = EntityUtils.toString(resEntityGet); 
       Log.i("GET RESPONSE", responseString.trim()); 
      } 
     } catch (Exception e) { 
      Log.d("ANDRO_ASYNC_ERROR", "Error is " + e.toString()); 
     } 
     Log.d("ANDRO_ASYNC_RESPONSE", responseString.trim()); 
     client.getConnectionManager().shutdown(); 
     return responseString.trim(); 

    } 

    @Override 
    protected void onPostExecute(String result) { 
     super.onPostExecute(result); 
    } 

} 

Answer 2

Вы можете обновите Views, которые выполняются на UI Thread после того, как вы получите результат с помощью AsyncTaskonPostExecute(). Кроме того, для начала необходимо позвонить AsyncTaskexecute() за AsyncTask.