动态列表视图添加“加载更多项目"在滚动的末尾 [英] dynamic listview adding "Load more items" at the end of scroll

问题描述

我有一个列表视图，它通过 Json 从 sqlite 数据库中获取数据.

I have a listview which is fetching data from sqlite database by Json.

我想把它变成动态列表视图，在滚动结束时，加载更多项目"出现在列表的页脚，同时加载更多项目并将它们添加到适配器(例如每次 10 个项目).我在实现此功能时遇到问题.请帮我解决.谢谢.

I want to turn it into dynamic listview that at the end of scroll, a "load more items" appears in the footer of the list while loading more items and adding them to the adapter (for example 10 items each time). I have problem in implementing this feature. Please help me with it. Thanks.

public class AllProductsActivity extends Activity {

... defining variables...;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    new LoadAllProducts().execute();

}

class LoadAllProducts extends AsyncTask<String, String, String> {

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        ... progress dialog...
    }

    protected String doInBackground(String... args) {
        countryList = new ArrayList<Country>();
        List<NameValuePair> params = new ArrayList<NameValuePair>();
        JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params);

        Log.d("All Products: ", json.toString());

        try {
            // Checking for SUCCESS TAG
            int success = json.getInt(TAG_SUCCESS);

            if (success == 1) {
                // products found
                // Getting Array of Products
                products = json.getJSONArray(TAG_PRODUCTS);

                // looping through All Products
                for (int i = 0; i < products.length(); i++) {
                    JSONObject c = products.getJSONObject(i);

                    // Storing each json item in variable
                    String id = c.getString(TAG_PID);
                    String name = c.getString(TAG_NAME);
                    String description = c.getString(TAG_DESCRIPTION);
                    String due_date = c.getString(TAG_DUE_DATE);
                    String staff = c.getString(TAG_STAFF);
                    String status = c.getString(TAG_STATUS);

                    country = new Country(id,name,description,
                            due_date, staff, status);
                    countryList.add(country);
                }
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }

        return null;
    }

    protected void onPostExecute(String file_url) {
        pDialog.dismiss();
        runOnUiThread(new Runnable() {
            public void run() {

                displayListView();

            }
        });
    }
}

private void displayListView() {
    dataAdapter = new MyCustomAdapter(this,
            R.layout.country_info, countryList);
    ListView listView = (ListView) findViewById(R.id.listView1);
    listView.setAdapter(dataAdapter);
}

private class MyCustomAdapter extends ArrayAdapter<Country> {

    ... blah blah blah ...

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        ViewHolder holder = null;
        Log.v("ConvertView", String.valueOf(position));
        if (convertView == null) {
        ... blah blah blah ...
        }

        return convertView;
    }
}
}

推荐答案

你试试下面的代码

list.setOnScrollListener(new OnScrollListener() {

        public void onScrollStateChanged(AbsListView view, int scrollState) {


        }

        public void onScroll(AbsListView view, int firstVisibleItem,
                int visibleItemCount, int totalItemCount) {

            if(firstVisibleItem+visibleItemCount == totalItemCount && totalItemCount!=0)
            {
                if(flag_loading == false)
                {
                    flag_loading = true;
                    additems();
                }
            }
        }
    });

在additem() 中添加接下来的10 项到数组列表并将flag_loading 设置为false.并调用 notifydatasetchanged.它应该可以工作.

in the additem() add the next 10 items to array list and set the flag_loading as false. and call notifydatasetchanged. it should work.

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