java - 将更多数据加载到 ListView - Android

Question

我已经实现了一个 ListView ，其中通过异步任务加载数据，为了加载更多数据，我使用了此代码发现here (完全复制粘贴)

主要 Activity

class load_data extends AsyncTask<Integer, Void, Void>{

// This asynctask takes in a page number as argument and depending on that page number
// data is loaded and stored in various String[] arrays and their length is extended as     new items are loaded

protected void onPostExecute(Void result) {

if(adapter == null){
            adapter = new Listadapter(Main.this,String[],String[],String[]);
            list.setAdapter(adapter);

            }
            else if(adapter != null){

                adapter.notifyDataSetChanged();
            }

}
    }

此任务称为 new load_data().execute(1);

在此代码之后，我从上面的链接加载了更多数据 fragment 一切工作完美，没有语法错误，在我的例子中，数据在达到给定阈值(20)后加载，但是没有显示新数据。如何通知适配器已添加更多数据或数据已更改谢谢!.

编辑:加载更多类

class EndlessScrollListener implements OnScrollListener {

            private int visibleThreshold = 5;
            private int currentPage = 1;
            private int previousTotal = 0;
            private boolean loading = true;

            public EndlessScrollListener() {
            }

            public EndlessScrollListener(int visibleThreshold) {
                this.visibleThreshold = visibleThreshold;
            }

            @Override
            public void onScroll(AbsListView view, int firstVisibleItem,
                    int visibleItemCount, int totalItemCount) {
                if (loading) {
                    if (totalItemCount > previousTotal) {
                        loading = false;
                        previousTotal = totalItemCount;
                        currentPage++;
                    }
                }
                if (!loading && (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold)) {
                    // I load the next page of gigs using a background task,
                    // but you can call any function here.
                    new load_data().execute(currentPage);
                    adapter.notifyDataSetChanged();
                    loading = true;
                }
            }

            @Override
            public void onScrollStateChanged(AbsListView view, int scrollState) {
            }
        }

list.setOnScrollListener(new EndlessScrollListener(20)); // 20 being the threshold

Answer 1

终于!对于那些遇到同样问题的人，我有解决方案。

我注意到adapter.notifyDataSetChanged();如果您使用 String[] 数组来存储显示在 ListView 行中的数据，则不起作用。

如果您使用 List<String> list = new ArrayList<String>();并将数据存储在 ListView 将使用新数据更新:)