Question

任何人都可以帮助我吗？我想在使用AsyncTask.向上和向下滚动时加载更多数据我尝试使用下面的代码但是当我向下滚动时它只加载了10个数据，它显示相同的数据。它不会加载新数据。

这是我的代码：

MainActivity.java

@Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, final ViewGroup container, Bundle savedInstanceState) {
        view = inflater.inflate(R.layout.home_fragment, container, false);
        arraylist1 = new ArrayList<>();
        adapter = new ListViewAdapter(view.getContext(), R.layout.list_view_adapter, arraylist1);
        listOfNews = (ListView) view.findViewById(R.id.listView);

        //progress bar
        dialog = new ProgressDialog(HotNewsFrag.this.getActivity());
        dialog.setMessage("Loading News");
        dialog.setCancelable(true);

        //class to parse data from json
        new ReadJSON().execute(url);

        return view;
    }

ListViewAdapter.java

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;
    }
}

ReadJSON AsyncTask

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();
    }
}

Answer 1

如果您想要获取有关滚动的新数据并删除，请更新每次通话中的页码或更新网址 onPostExecute() 来自ReadJSON类中的onCreate()方法，并在listOfNews = (ListView) view.findViewById(R.id.listView);方法中将其设置为listview

https://host:port/hcmCoreApi/resources/11.12.1.0/emps/?q=DateOfBirth='1991-09-19'&PersonNumber=240

当我向下滚动时，它总是加载更多相同的数据

1 个答案: