AsyncTaskLoaderGist

public class MainActivity 
  extends FragmentActivity 
  implements LoaderCallbacks<String> {
 
  ProgressDialog dialog;
  String json;
  
  private static final int MEU_LOADER = 0;
 
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
 
    // Recovering the status of the Activity
    if (savedInstanceState != null) {
      json = savedInstanceState.getString("valores");
      updateScreen();
    }
 
    // This class manages all Loaders
    LoaderManager lm = getSupportLoaderManager();
 
    // If JSON has not yet been downloaded
    if (json == null) {
      // Displays the dialog
      dialog = ProgressDialog.show(
        this, "Wait...", "Downloading tweets");
 
      // And initializes the Loader (if it has already been initialized, it will just continue)
      lm.initLoader(MEU_LOADER, null, this);
    }
  }
 
  @Override
  protected void onDestroy() {
    super.onDestroy();
    // If you are viewing progress, remove it
    if (dialog != null && dialog.isShowing()) 
      dialog.dismiss();
  } 
 
  @Override
  protected void onSaveInstanceState(Bundle outState){
    super.onSaveInstanceState(outState);
    // Saving the status of the Activity
    outState.putString("valores", json);
  }
 
  // Interface Methods LoaderCallbacks
  @Override
  public Loader<String> onCreateLoader(
    int id, Bundle args) {
    // Instances and returns the AsyncTaskLoader
    return new MinhaAsyncTask(this);
  }
 
  @Override
  public void onLoadFinished(Loader<String> loader, 
    String data) {
    // Called when the Loader finishes its work
    // Here, we assign the result to the json attribute and hide the dialog
    json = data;
    updateScreen();
    dialog.dismiss();
  }
 
  @Override
  public void onLoaderReset(Loader<String> loader) {
     // Called if the Loader is reset
     Log.d("NGVL", "onLoaderReset");
  }
 
  // AsyncTaskLoader
  public static class MinhaAsyncTask 
    extends AsyncTaskLoader<String> {
 
    // The downloaded JSON will be stored here to be passed to Activity
    String data;
 
    public MinhaAsyncTask(Context context) {
      super(context);
    }
 
    @Override
    protected void onStartLoading() {
      // If you have not downloaded the data, do it now!
      if (data == null) {
        forceLoad();
 
      // If you have already downloaded, just deliver the result
      } else {
        deliverResult(data);
      }
    }
 
    @Override
    public String loadInBackground() {
      // In this method the JSON will be downloaded
      return downloadJSON();
    }
  }
}