我的代码私有无效更新列表中出现错误“this，mCommentList”的所有内容都用红色下划线标出

Question

有人可以帮助我吗？我正在遵循一个很长的教程并且到最后并且无法修复此错误。从公共无效更新列表开始，下面的代码用红色加下划线，我似乎无法解决问题。

public class readComments extends ListActivity {


private ProgressDialog pDialog;


private static final String READ_COMMENTS_URL = "http://120.120.1.100    /webservice/comments.php";


private static final String TAG_SUCCESS = "success";
private static final String TAG_TITLE = "title";
private static final String TAG_POSTS = "posts";
private static final String TAG_POST_ID = "post_id";
private static final String TAG_USERNAME = "username";
private static final String TAG_MESSAGE = "message";




private JSONArray mComments = null;

private ArrayList<HashMap<String, String>> mCommentList;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.read_comments);
}

@Override
protected void onResume() {
    // TODO Auto-generated method stub
    super.onResume();
    //loading the comments via AsyncTask
    new LoadComments().execute();
}

public void addComment(View v)
{
    Intent i = new Intent(readComments.this, AddComment.class);
    startActivity(i);
}


public void updateJSONdata() {

}


private void updateList() {

}

public class LoadComments extends AsyncTask<Void, Void, Boolean> {

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(readComments.this);
        pDialog.setMessage("Loading Comments...");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(true);
        pDialog.show();
    }
    public void updateJSONdata() {



        mCommentList = new ArrayList<HashMap<String, String>>();


        JSONParser jParser = new JSONParser();

        JSONObject json = jParser.getJSONFromUrl(READ_COMMENTS_URL);


        try {

            mComments = json.getJSONArray(TAG_POSTS);

            for (int i = 0; i < mComments.length(); i++) {
                JSONObject c = mComments.getJSONObject(i);


                String title = c.getString(TAG_TITLE);
                String content = c.getString(TAG_MESSAGE);
                String username = c.getString(TAG_USERNAME);



                HashMap<String, String> map = new HashMap<String, String>();

                map.put(TAG_TITLE, title);
                map.put(TAG_MESSAGE, content);
                map.put(TAG_USERNAME, username);

                mCommentList.add(map);

            }

        } catch (JSONException e) {
            e.printStackTrace();
        }
    }

//Problem starts here everything underlined in red
    @Override
    private void updateList() {
        ListAdapter adapter = new SimpleAdapter(this, mCommentList,
                R.layout.single_post, new String[]{TAG_TITLE, TAG_MESSAGE,
                TAG_USERNAME}, new int[]{R.id.title, R.id.message,
                R.id.username});


        setListAdapter(adapter);

        ListView lv = getListView();
        lv.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                                    int position, long id) {


            }
        });
    }