jSoup method closes android App

Question

I'm trying to use jsoup to display temperature of Boston from a website as a toast message in an android app. My Java program looks like this:

public static void showWeather() throws IOException
{
    Document doc = Jsoup.connect("http://www.wunderground.com/US/ma/boston.html?MR=1").get();
    Elements languages = doc.select("#tempActual span.b ");


    for(Element langElement: languages)
    {
        //System.out.println(" The temperature in Boston: "+langElement.text()+ " F");

    }

}

The Java program works Okay and prints the temperature of Boston to the screen. I want to use this method to try to display the temperature as a toast in a simple android app, but when I try to run to method (without the print statement of course) in the onCreate method in my android activity, the program closes automatically. Here's my onCreate method:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    addKeyListener();

    try {
        showWeather();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

Can anybody please tell how to run this java program in my android activity? I don't know how to treat the try/catch clause properly. I tried put toast in the catch clause but to no avail. Please help.

Answer 1

AsyncTask enables proper and easy use of the UI thread. This class allows to perform background operations and publish results on the UI thread without having to manipulate threads and/or handlers.

Reference:
http://developer.android.com/reference/android/os/AsyncTask.html

Usage
AsyncTask must be subclassed to be used. The subclass will override at least one method ( doInBackground(Params...) ), and most often will override a second one ( onPostExecute(Result) .)

Here is an example of subclassing:

private class DownloadFilesTask extends AsyncTask<URL, Integer, Long> {
  protected Long doInBackground(URL... urls) {
     int count = urls.length;
     long totalSize = 0;
     for (int i = 0; i < count; i++) {
         totalSize += Downloader.downloadFile(urls[i]);
         publishProgress((int) ((i / (float) count) * 100));
         // Escape early if cancel() is called
         if (isCancelled()) break;
     }
     return totalSize;
  }

  protected void onProgressUpdate(Integer... progress) {
      setProgressPercent(progress[0]);
  }

  protected void onPostExecute(Long result) {
      showDialog("Downloaded " + result + " bytes");
  }
 }

Once created, a task is executed very simply:

new DownloadFilesTask().execute(url1, url2, url3);