如何从另一个类访问内部AsyncTask类并检索其结果

Question

新手在这里，我试图从内部AsyncTask拨打AsyncTask，如下所示，但它不起作用。有人能指出我正确的方向吗？当我从setCrowdSubtitle调用方法card1时，它没关系，但在尝试从AsyncTask类设置时却没有。

class Card extends CardBase {

public void setCrowdTitle(String cTitle) {
    CardHeader header = new CardHeader(getContext());
    header.setTitle(cTitle);
    header.setButtonExpandVisible(true);
    addCardHeader(header);
}

public class HttpAsyncTask extends AsyncTask<String, Void, String> {
        @Override
        protected String doInBackground(String... urls) {

        return GET(urls[0]);
        }

        @Override
        protected void onPostExecute(String result) {

        }
}
}

class Activity {

private class LoaderAsyncTask extends AsyncTask<Void, Void,  ArrayList<Card>> {
    @Override
    protected ArrayList<Card> doInBackground(Void... params) {

        if (isAdded()) {
            ArrayList<Card> cards = initcrowdCard();
            return cards;
        } else
            return null;
    }

    @Override
    protected void onPostExecute(ArrayList<Card> cards) {

        onRefreshComplete(cards);
}

private ArrayList<Card> initcrowdCard() {

    ArrayList<Card> cards = new ArrayList<>();

    Card card1 = new Card(this.getActivity(), R.layout.crowd_card);
    card1.setCrowdSubtitle("Url");
    cards.add(card1);

    Card card2 = new Card(this.getActivity(), R.layout.crowd_card);
    card2.new HttpAsyncTask() {
        @Override
        public void onPostExecute(String picUrl) {
            card2.setCrowdSubtitle(picUrl);
        }
    }.execute(phpScript);
   cards.add(card2);
}
}