Question

I have a PreferenceActivity that gets its data from a web service(Call forward Numbers, Voicemail status etc)

The class looks like this :

public class SettingsActivity extends PreferenceActivity
{
UserController userControl;
ListPreference lp;
public SharedPreferences prefs;
@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    userControl = new UserController(getParent());
    addPreferencesFromResource(R.layout.settings);

    new PullNumbersTask().execute();

}

   private class PullNumbersTask extends AsyncTask<Void, Void, String[]>
{
    private ProgressDialog Dialog;
    private String[] numbers;
    private boolean vmStatus;
    private String[] cfInfo;
    public PullNumbersTask()
    {
         Dialog = new ProgressDialog(getParent());
         Dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
    }


    protected void onPreExecute() 
    {
        Dialog.setMessage("Henter brugerindstillinger..");
        Dialog.show();
    }

    @Override
    protected String[] doInBackground(Void... arg0) 
    {
        numbers = userControl.GetNumbers(); // Returns a String array containing available numbers
        Dialog.setProgress(30);
        vmStatus = userControl.GetVoicemailStatus(); // Returns a boolean containing voicemail status(enabled/disabled)
        Dialog.setProgress(80);
        cfInfo = userControl.GetCallForwardInfo(); // Returns a String array containing Call forward info.
        Dialog.setProgress(100);

        return null;
    }



     protected void onPostExecute(String[] result) 
     {
        lp = (ListPreference) findPreference("shownumber_list");
        lp.setEntries(result);
        lp.setEntryValues(result);
        Dialog.dismiss();
     }

}

I decided that I want a single AsyncTask call to perform all my web service calls – But how do I Set the data of my preferences onPostExecute?

Answer 1

Instead of using a String[] as return value from the doInBackground() method, define a class inside your AyncTask with the fields you need to be passed to the onPostExecute() method.

Moreover you should avoid updating the progress dialog directly from the doInBackground() as it will not be performed in the UI thread. The AsynClass provides the possibility to pass a parameter to a onProgressUpdate() method to reflect changes in the progress of background execution.

More details here: http://developer.android.com/reference/android/os/AsyncTask.html