在listview Android中解析Rss feed

Question

在我的Android应用程序中，我成功解析了网站上的JSON代码。但是当我尝试从网站解析RSS feed（XML）时，我收到了一个错误。能帮我解决这个问题。

public class FeedListActivity extends Activity {

    private ArrayList<FeedItem> feedList = null;
    private ProgressBar progressbar = null;
    private ListView feedListView = null;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_posts_list);
        progressbar = (ProgressBar) findViewById(R.id.progressBar);
        String url = "http://javatechig.com/api/get_category_posts/?dev=1&slug=android";
        new DownloadFilesTask().execute(url);
    }

    public void updateList() {
        feedListView= (ListView) findViewById(R.id.custom_list);
        feedListView.setVisibility(View.VISIBLE);
        progressbar.setVisibility(View.GONE);

        feedListView.setAdapter(new CustomListAdapter(this, feedList));
        feedListView.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> a, View v, int position, long id) {
                Object o = feedListView.getItemAtPosition(position);
                FeedItem newsData = (FeedItem) o;

                Intent intent = new Intent(FeedListActivity.this, FeedDetailsActivity.class);
                intent.putExtra("feed", newsData);
                startActivity(intent);
            }
        });
    }

    private class DownloadFilesTask extends AsyncTask<String, Integer, Void> {

        @Override
        protected void onProgressUpdate(Integer... values) {
        }

        @Override
        protected void onPostExecute(Void result) {
            if (null != feedList) {
                updateList();
            }
        }

        @Override
        protected Void doInBackground(String... params) {
            String url = params[0];

            // getting JSON string from URL
            JSONObject json = getJSONFromUrl(url);

            //parsing json data
            parseJson(json);
            return null;
        }
    }


    public JSONObject getJSONFromUrl(String url) {
        InputStream is = null;
        JSONObject jObj = null;
        String json = null;

        // Making HTTP request
        try {
            // defaultHttpClient
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpPost httpPost = new HttpPost(url);

            HttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();

            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    is, "iso-8859-1"), 8);
            StringBuilder sb = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
            is.close();
            json = sb.toString();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        try {
            jObj = new JSONObject(json);
        } catch (JSONException e) {
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }

        // return JSON String
        return jObj;

    }

    public void parseJson(JSONObject json) {
        try {

            // parsing json object
            if (json.getString("status").equalsIgnoreCase("ok")) {
                JSONArray posts = json.getJSONArray("posts");

                feedList = new ArrayList<FeedItem>();

                for (int i = 0; i < posts.length(); i++) {
                    JSONObject post = (JSONObject) posts.getJSONObject(i);
                    FeedItem item = new FeedItem();
                    item.setTitle(post.getString("title"));
                    item.setDate(post.getString("date"));
                    item.setId(post.getString("id"));
                    item.setUrl(post.getString("url"));
                    item.setContent(post.getString("content"));
                    JSONArray attachments = post.getJSONArray("attachments");

                    if (null != attachments && attachments.length() > 0) {
                        JSONObject attachment = attachments.getJSONObject(0);
                        if (attachment != null)
                            item.setAttachmentUrl(attachment.getString("url"));
                    }

                    feedList.add(item);
                }
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }

}