Android 当我向下滚动时，它总是加载更多相同的数据

有人能帮我吗？我想在使用AsyncTask上下滚动时加载更多数据。我试图使用下面的代码，但当我向下滚动时，它只加载了10个以上的数据。除此之外，它还显示相同的数据。它不会加载新数据

这是我的代码：

MainActivity.java

ListViewAdapter.java

ReadJSON异步任务

---

如果您想在滚动时获得新数据并删除，请在每次通话中更新页码或更新url listOfNews.setAdapteradapter； 从ReadJSON类中的onPostExecute方法，并在之后的onCreate方法中将其设置为listview

listOfNews = (ListView) view.findViewById(R.id.listView);

public class ListViewAdapter extends ArrayAdapter<HotNews> {
    private final LayoutInflater mInflater;
    Context context;
    ArrayList<HotNews> arrayList;
    ImageView image;
    TextView doer;
    TextView date;
    TextView text;
    Days day = new Days();

    public ListViewAdapter(Context context, int resource, ArrayList<HotNews> arrayList) {
        super(context, resource, arrayList);
        mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        this.arrayList = arrayList;
        this.context = context;
    }

    @Override
    public int getCount() {
        if (arrayList == null) {
            return 0;
        }
        return arrayList.size();
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        final HotNews news;
        View v = convertView;

        if (v == null) {
            v = mInflater.inflate(R.layout.list_view_adapter, parent, false);
        }
        image = (ImageView) v.findViewById(R.id.imagetitle);
        title = (TextView) v.findViewById(R.id.txtTitle);
        doer = (TextView) v.findViewById(R.id.doer);
        date = (TextView) v.findViewById(R.id.txtdate);
        text = (TextView) v.findViewById(R.id.text);

        news = getItem(position);
        Picasso.with(getContext()).load(url + news.getImage()).error(R.drawable.dap).noFade().into(image);

        title.setText(news.getTitle());
        doer.setText("ព័ត៍មានដោយ៖" + news.getDoer());
        date.setText(day.Days(news.getDate()) + ":" + news.getTime());
        text.setText(news.getContent());

        //set onItemListener
        listOfNews.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Toast.makeText(getContext(), "Stop Clicking me", Toast.LENGTH_SHORT).show();
                Intent detail = new Intent(getContext(), HotNewsDetail.class);
                detail.putExtra(newsid, String.valueOf(getItem(position).getId()));
                startActivity(detail);
            }
        });
        listOfNews.setOnScrollListener(new AbsListView.OnScrollListener() {

            @Override
            public void onScrollStateChanged(AbsListView view, int scrollState) {
                if (scrollState == 0) {
                    // new loadMoreListView().execute();
                }
            }

            @Override
            public void onScroll(AbsListView view, int firstVisibleItem,
                                 int visibleItemCount, int totalItemCount) {
                final int lastItem = firstVisibleItem + visibleItemCount;
                if (lastItem == totalItemCount) {
                    new ReadJSON().execute(url);
                } else {

                }
            }
        });
        return v;
    }
}

private class ReadJSON extends AsyncTask<String, Integer, String> {

    @Override
    protected String doInBackground(String... url) {
        String st = readURL(url[0]);
        Log.d("st", st);
        return st;
    }

    @Override
    protected void onPostExecute(String content) {

        try {
            JSONObject jsonObject = new JSONObject(content);
            JSONArray jsonArray = jsonObject.optJSONArray("data");
            for (int i = 0; i < jsonArray.length(); i++) {

                Log.d(i + ":jsonArray object", jsonArray.toString() + " size= " + jsonArray.length());
                JSONObject productObject = jsonArray.optJSONObject(i);
                JSONObject img = productObject.optJSONObject("image");
                if (img != null) {
                    JSONObject da = img.optJSONObject("data");
                    if (da != null) {
                        arraylist1.add(new HotNews(
                                da.optString("filename"),
                                productObject.optString("title"),
                                productObject.optString("article_by"),
                                productObject.optString("date_publish"),
                                productObject.optString("short_description"),
                                productObject.optInt("id"),
                                productObject.optString("time_publish")
                        ));


                        Log.d("jsonArray news list1", arraylist1.size() + "");

                    }

                } else {
                    arraylist1.add(new HotNews(
                            "",
                            productObject.optString("title"),
                            productObject.optString("article_by"),
                            productObject.optString("date_publish"),
                            productObject.optString("short_description"),
                            productObject.optInt("id"),
                            productObject.optString("time_publish")

                    ));
                }
            }
            listOfNews.setAdapter(adapter);
            adapter.notifyDataSetChanged();
            dialog.dismiss();

            // super.onPostExecute(content);
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }

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

listOfNews = (ListView) view.findViewById(R.id.listView);