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POnullPointerException when using Aysnctask, android
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  1. POnullPointerException when using Aysnctask, android
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    copied!<p>I am writing an android application to get the current weather using latitude , longitude using openWeatherMap API. I used Aysnctask to get the weather, but the application crashes and it gives me a nullPointerException.</p> <p>here the aysnctask:</p> <pre><code>private class JSONWeatherTask extends AsyncTask&lt;String, Void, Weather&gt; { @Override protected Weather doInBackground(String... params) { Weather weather = new Weather(); // String data = ( (new WeatherHttpClient()).getWeatherData(params[0])); String data = ( (new WeatherHttpClient()).getWeatherData(params[0],params[1])); try { weather = JSONWeatherParser.getWeather(data); // Let's retrieve the icon weather.iconData = ( (new WeatherHttpClient()).getImage(weather.currentCondition.getIcon())); } catch (JSONException e) { e.printStackTrace(); } return weather; } @Override protected void onPostExecute(Weather weather) { super.onPostExecute(weather); if (weather.iconData != null &amp;&amp; weather.iconData.length &gt; 0) { Bitmap img = BitmapFactory.decodeByteArray(weather.iconData, 0, weather.iconData.length); imgView.setImageBitmap(img); } condDescr.setText(weather.currentCondition.getCondition() + "(" + weather.currentCondition.getDescr() + ")"); temp.setText("" + Math.round((weather.temperature.getTemp() - 275.15)) + "°C"); hum.setText("" + weather.currentCondition.getHumidity() + "%"); press.setText("" + weather.currentCondition.getPressure() + " hPa"); windSpeed.setText("" + weather.wind.getSpeed() + " mps"); windDeg.setText("" + weather.wind.getDeg() + "°"); } } </code></pre> <p>the parameters of doInBackground method should be current latitude, longitude. I call the aysnktask like this:</p> <pre><code>JSONWeatherTask task = new JSONWeatherTask(); task.execute(new String[]{currentLatitude,currentLongitude}); </code></pre> <p>and I make the connection to openWeatherMap like this:</p> <pre><code>public String getWeatherData(String lat,String lng) { HttpURLConnection con = null ; InputStream is = null; try { con=(HttpURLConnection)(new URL("http://api.openweathermap.org/data/2.5/weather?lat=%"+Double.parseDouble(lat)+"&amp;lon="+Double.parseDouble(lng))).openConnection(); con.setRequestMethod("GET"); con.setDoInput(true); con.setDoOutput(true); con.connect(); // Let's read the response StringBuffer buffer = new StringBuffer(); is = con.getInputStream(); BufferedReader br = new BufferedReader(new InputStreamReader(is)); String line = null; while ( (line = br.readLine()) != null ) buffer.append(line + "\r\n"); is.close(); con.disconnect(); return buffer.toString(); } catch(Throwable t) { t.printStackTrace(); } finally { try { is.close(); } catch(Throwable t) {} try { con.disconnect(); } catch(Throwable t) {} } return null; } </code></pre> <p>the nullPointerException is at this line :</p> <pre><code>weather = JSONWeatherParser.getWeather(data); </code></pre> <p>here is the logCat:</p> <pre><code>12-03 11:34:29.110: E/AndroidRuntime(16271): FATAL EXCEPTION: AsyncTask #1 12-03 11:34:29.110: E/AndroidRuntime(16271): java.lang.RuntimeException: An error occured while executing doInBackground() 12-03 11:34:29.110: E/AndroidRuntime(16271): at android.os.AsyncTask$3.done(AsyncTask.java:299) 12-03 11:34:29.110: E/AndroidRuntime(16271): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273) 12-03 11:34:29.110: E/AndroidRuntime(16271): at java.util.concurrent.FutureTask.setException(FutureTask.java:124) 12-03 11:34:29.110: E/AndroidRuntime(16271): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307) 12-03 11:34:29.110: E/AndroidRuntime(16271): at java.util.concurrent.FutureTask.run(FutureTask.java:137) 12-03 11:34:29.110: E/AndroidRuntime(16271): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230) 12-03 11:34:29.110: E/AndroidRuntime(16271): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076) 12-03 11:34:29.110: E/AndroidRuntime(16271): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569) 12-03 11:34:29.110: E/AndroidRuntime(16271): at java.lang.Thread.run(Thread.java:856) 12-03 11:34:29.110: E/AndroidRuntime(16271): Caused by: java.lang.NullPointerException 12-03 11:34:29.110: E/AndroidRuntime(16271): at org.json.JSONTokener.nextCleanInternal(JSONTokener.java:116) 12-03 11:34:29.110: E/AndroidRuntime(16271): at org.json.JSONTokener.nextValue(JSONTokener.java:94) 12-03 11:34:29.110: E/AndroidRuntime(16271): at org.json.JSONObject.&lt;init&gt;(JSONObject.java:154) 12-03 11:34:29.110: E/AndroidRuntime(16271): at org.json.JSONObject.&lt;init&gt;(JSONObject.java:171) 12-03 11:34:29.110: E/AndroidRuntime(16271): at com.survivingwithandroid.weatherapp.JSONWeatherParser.getWeather(JSONWeatherParser.java:42) 12-03 11:34:29.110: E/AndroidRuntime(16271): at com.survivingwithandroid.weatherapp.MainActivity$JSONWeatherTask.doInBackground(MainActivity.java:290) 12-03 11:34:29.110: E/AndroidRuntime(16271): at com.survivingwithandroid.weatherapp.MainActivity$JSONWeatherTask.doInBackground(MainActivity.java:1) 12-03 11:34:29.110: E/AndroidRuntime(16271): at android.os.AsyncTask$2.call(AsyncTask.java:287) 12-03 11:34:29.110: E/AndroidRuntime(16271): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305) </code></pre> <p>this is getWeather method :</p> <pre><code>public static Weather getWeather(String data) throws JSONException { Weather weather = new Weather(); // We create out JSONObject from the data JSONObject jObj = new JSONObject(data); // We start extracting the info Location1 loc = new Location1(); JSONObject coordObj = getObject("coord", jObj); loc.setLatitude(getFloat("lat", coordObj)); loc.setLongitude(getFloat("lon", coordObj)); JSONObject sysObj = getObject("sys", jObj); loc.setCountry(getString("country", sysObj)); loc.setSunrise(getInt("sunrise", sysObj)); loc.setSunset(getInt("sunset", sysObj)); loc.setCity(getString("name", jObj)); weather.location = loc; // We get weather info (This is an array) JSONArray jArr = jObj.getJSONArray("weather"); // We use only the first value JSONObject JSONWeather = jArr.getJSONObject(0); weather.currentCondition.setWeatherId(getInt("id", JSONWeather)); weather.currentCondition.setDescr(getString("description", JSONWeather)); weather.currentCondition.setCondition(getString("main", JSONWeather)); weather.currentCondition.setIcon(getString("icon", JSONWeather)); JSONObject mainObj = getObject("main", jObj); weather.currentCondition.setHumidity(getInt("humidity", mainObj)); weather.currentCondition.setPressure(getInt("pressure", mainObj)); weather.temperature.setMaxTemp(getFloat("temp_max", mainObj)); weather.temperature.setMinTemp(getFloat("temp_min", mainObj)); weather.temperature.setTemp(getFloat("temp", mainObj)); // Wind JSONObject wObj = getObject("wind", jObj); weather.wind.setSpeed(getFloat("speed", wObj)); weather.wind.setDeg(getFloat("deg", wObj)); // Clouds JSONObject cObj = getObject("clouds", jObj); weather.clouds.setPerc(getInt("all", cObj)); // We download the icon to show return weather; } </code></pre>
 

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