Java Android ListView添加项目

Question

我想在Load-More中实施ListView功能。

这是我的代码：

public class MainActivity extends Activity {

    int url_page = 0;
    private static String URL = "http://MyURL&page_no=";
    ArrayList<ItemInfo> products = new ArrayList<ItemInfo>();
    BoxAdapter boxAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        new AsyncTaskParseJson().execute();
    }


    public class AsyncTaskParseJson extends AsyncTask<String, String, String> {

       final String TAG = "AsyncTaskParseJson.java";
       JSONArray dataJsonArr = null;

       @Override
       protected void onPreExecute() {}

       @Override
       protected String doInBackground(String... arg0) {

           try {


               JsonParser jParser = new JsonParser();
               JSONObject json = jParser.getJSONFromUrl(URL+"0");
               dataJsonArr = json.getJSONArray("data");

               for (int i = 0; i < dataJsonArr.length(); i++) {

                   JSONObject c = dataJsonArr.getJSONObject(i);

                   String nickname = c.getString("nickname");
                   String description = c.getString("description");
                   products.add(new ItemInfo(nickname, description));
               }

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

           return null;
       }

       @Override
       protected void onPostExecute(String strFromDoInBg) 
       {
            SetAdapter();
       }
   }

    public void SetAdapter()
    {
        boxAdapter = new BoxAdapter(this, products);
        ListView lvMain = (ListView) findViewById(R.id.list);
       lvMain.setOnItemClickListener(new OnItemClickListener() {

           @Override
           public void onItemClick(AdapterView<?> parent, View view,
                   int position, long id) 
           {
            ListView lvMain = (ListView) findViewById(R.id.list);
            int pos = lvMain.getPositionForView(view);
               ItemInfo p = boxAdapter.getItem(pos);
               //
               String username = p.username;
               String description = p.description;
               // Starting single contact activity
               Intent in = new Intent(getApplicationContext(),
                    OnClickActivity.class);
               in.putExtra("username", username);
               in.putExtra("description", description);
               startActivity(in);
           }
       });
        lvMain.setAdapter(boxAdapter);
        lvMain.setOnScrollListener(new OnScrollListener()
        {

            @Override
            public void onScroll(AbsListView view, int firstVisibleItem,
                    int visibleItemCount, int totalItemCount) {
                // TODO Auto-generated method stub
                    ListView lvMain = (ListView) findViewById(R.id.list);
                    if(firstVisibleItem + visibleItemCount >= totalItemCount) {
                        boxAdapter.loadAdditionalItems();
                    }
            }

            @Override
            public void onScrollStateChanged(AbsListView view, int scrollState) {
                // TODO Auto-generated method stub
            }

        });

    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}

我将此添加到onScroll事件：

if (lvMain.getLastVisiblePosition() >= lvMain.getCount())
                    {
                        url_page = url_page + 1;
                        new LoadLastestPost().execute();
                    }

as asaskask：

public class LoadLastestPost extends AsyncTask<String, String, String> {

           final String TAG = "LoadLastestPost.java";
           JSONArray dataJsonArr = null;

           @Override
           protected void onPreExecute() {}

           @Override
           protected String doInBackground(String... arg0) {

               try {


                   JsonParser jParser = new JsonParser();
                   String newURL = URL + String.valueOf(url_page);
                   JSONObject json = jParser.getJSONFromUrl(newURL);
                   dataJsonArr = json.getJSONArray("data");

                   for (int i = 0; i < dataJsonArr.length(); i++) {

                       JSONObject c = dataJsonArr.getJSONObject(i);

                       String nickname = c.getString("nickname");
                       String description = c.getString("description");
                       products.add(new ItemInfo(nickname, description));
                   }

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

               return null;
           }

           @Override
           protected void onPostExecute(String strFromDoInBg) 
           {
               LoadMoreItem();
           }
       }

    private void LoadMoreItem()
    {
        ListView lvMain = (ListView) findViewById(R.id.list);
        boxAdapter = null;
        boxAdapter = new BoxAdapter(this, products);
        lvMain.setAdapter(boxAdapter);
        boxAdapter.notifyDataSetChanged();
    }

但它不起作用;（那需要修复？ P.S我显示10项，并加载已经加载的10个响应。 我想在listview的末尾加载项目。