android - 如何使用异步任务返回对象？

Question

我试图在从异步任务解析后返回推文列表....但我没有从任务中取回数组列表。谁能提出解决方案？

public class Main extends ListActivity {
    String MY_APP_TAG = "com.list";

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ArrayList listItems = new ArrayList();
        new myAsyncTask().execute(listItems);

        setListAdapter(new ArrayAdapter(this, R.layout.tweet, R.id.tweet,listItems));
        ListView lv = getListView();
        lv.setTextFilterEnabled(true);
        lv.setOnItemClickListener(new OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                // When clicked, show a Toaster
                Toast.makeText(getApplicationContext(), ((TextView) view).getText(), Toast.LENGTH_SHORT).show();
            }
        });
    }

    private class myAsyncTask extends AsyncTask<ArrayList<Object>, Void, Void>
    {
        ArrayList<Object> listItems;
        ProgressDialog dialog;
        @Override
        protected void onPreExecute() {
            dialog = ProgressDialog.show(Main.this, "", "Loading....");
        }
        @Override
        protected Void doInBackground(ArrayList<Object>... params) {

            String host = "api.twitter.com";
            String twitterURL = "http://"+host+"/1/statuses/user_timeline.json?screen_name=i1990jain&amp;count;=10";
            try {
                HttpClient client = new DefaultHttpClient();
                BasicHttpContext localContext = new BasicHttpContext();
                HttpHost targetHost = new HttpHost(host, 80, "http");
                HttpGet httpget = new HttpGet(twitterURL);
                httpget.setHeader("Content-Type", "application/json");
                HttpResponse response = client.execute(targetHost, httpget, localContext);
                HttpEntity entity = response.getEntity();
                Object content = EntityUtils.toString(entity);
                Log.d(MY_APP_TAG, "OK: " + content.toString());

                JSONArray ja = new JSONArray(content.toString());

                for(int i = 0; i < ja.length(); i++){
                    JSONObject jo = ja.getJSONObject(i);
                    listItems.add(jo.getString("text"));
                }
            } catch(Exception e) {
                e.printStackTrace();
            }
            return null;
        }
        @Override
        protected void onPostExecute(Void result) {
            dialog.dismiss();
        }
    }
}

Answer 1

是 AsyncTask<Params, Progress, Result> .所以你应该将它声明为 AsyncTask<Void, Void, ArrayList<Object>> .

从 doInBackground 返回列表方法。