How to implement OnScrollListener in listview?

Question

I get 500 records from the server. I want to display 10 items in a list, and when the listview reaches the end, I need to load another 10, etc. I have seen many examples on the net, but I cannot resolve it. Help me.

Here is my code:

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.form);
    Seen = (ImageView) findViewById(R.id.SeenStatus);       


    new GetDescendingDate().execute();
    userArray = new ArrayList<listmodel>();

    ListView lv = getListView();


    lv.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
            // getting values from selected ListItem
            String Id = ((TextView) view.findViewById(R.id.txtId))
                    .getText().toString();

            // Starting single activity
            Intent in = new Intent(getApplicationContext(),
                    details.class);
            in.putExtra("TAG_Id", Id);
            startActivity(in);


    });



    }

}


private class GetDescendingDate extends AsyncTask<Void, Void, Void> {

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        // Showing progress dialog
        pDialog = new ProgressDialog(Atab.this);
        pDialog.setMessage("Loading...");
        pDialog.setCancelable(false);
        pDialog.show();

    }

    @TargetApi(Build.VERSION_CODES.GINGERBREAD)
    @Override
    protected Void doInBackground(Void... arg0) {

        JSONParser jParser = new JSONParser();

        // Getting JSON Array node
        JSONArray json;

        session = new SessionManager(getApplicationContext());
        session.checkLogin();
        HashMap<String, String> user = session.getUserDetails();
        String email = user.get(SessionManager.KEY_EMAIL);
        String Status = "New";
        String get;
        get = URL.Get;
        String url_new = get + email + "/" + Status + "/" + "SODD"
                + "/" + "null" + "/" + "0" + "/" + "10";
        try {
            json = jParser.getJSONFromUrl(url_new);

            if (json != null) {
                // looping through All Orders
                for (int i = 0; i < json.length(); i++) {
                    try {
                        JSONObject c = json.getJSONObject(i);

                        String number = c.getString("No");
                        String By = c.getString("By");
                        String Type = c.getString("Type");
                        String Descripton = c.getString("Desc");
                        String Date = c.getString("DateTime");
                        String Id = c.getString("Id");
                        String ONo = c.getString("ONo");
                        String FirstName = c        .getString("FirstName");
                        String Price = c.getString("Price");


                        listmodel list = new listmodel();
                        list.setId(Id);
                        list.setBy(By);
                        list.setType(Type);
                        list.setDescription(Descripton);
                        list.setDate(Date);
                        list.setPrice(Price);
                        list.setName(FirstName);

                        userArray.add(list);

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

            else {
                Log.e("New", "Couldn't get any data from the url");

            }
        } catch (JSONException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }

        return null;
    }

    protected void onPostExecute(Void result) {
        super.onPostExecute(result);

        if (pDialog.isShowing())
            pDialog.dismiss();

        adapter = new adapter(Atab.this,userArray);         
        setListAdapter(adapter);


    }

}

Answer 1

You can implement this.

 listView.setOnScrollListener(new OnScrollListener() {
        private int currentVisibleItemCount;
        private int currentScrollState;
        private int currentFirstVisibleItem;
        private int totalItem;
        private LinearLayout lBelow;


        @Override
        public void onScrollStateChanged(AbsListView view, int scrollState) {
            // TODO Auto-generated method stub
            this.currentScrollState = scrollState;
            this.isScrollCompleted();               
        }

        @Override
        public void onScroll(AbsListView view, int firstVisibleItem,
                int visibleItemCount, int totalItemCount) {
            // TODO Auto-generated method stub
            this.currentFirstVisibleItem = firstVisibleItem;
            this.currentVisibleItemCount = visibleItemCount;
            this.totalItem = totalItemCount;


        }

        private void isScrollCompleted() {
            if (totalItem - currentFirstVisibleItem == currentVisibleItemCount
                    && this.currentScrollState == SCROLL_STATE_IDLE) {
             /** To do code here*/


        }
    });

Answer 2

Easiest option

First you need to add a footer and assign an OnScrollListener

ProgressBar footer = new ProgressBar(this);
listView.addFooterView(footer);
listView.setOnScrollListener(scrollListener);

and this implementation of OnScrollListener

private AbsListView.OnScrollListener scrollListener = new AbsListView.OnScrollListener() {
        @Override
        public void onScrollStateChanged(AbsListView view, int scrollState) {

        }

        @Override
        public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
            int lastInScreen = firstVisibleItem + visibleItemCount;
            if(lastInScreen == totalItemCount && !isLoading){
                loadMoreItems(totalItemCount - 1);
                isLoading = true;
            }
        }
    };

server gave me records of 10 items

isLoading changes when download is complete

totalItemCount - 1start position ( footer is also a list item)

adapter.addAll(list); adapter.notifyDataSetChanged (); isLoading = false;

Answer 3

This is the following:

public OnScrollListener scrollListener = new OnScrollListener() 
{
    @Override
    public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) 
    { 
         if((firstVisibleItem + visibleItemCount) >= totalItemCount) && /*also maybe some condition else*/) 
         {    

             //here start next 10 items request                   
         }


    @Override
    public void onScrollStateChanged(AbsListView arg0, int arg1) {
            // TODO Auto-generated method stub

    }

};

If your server provides the next 10 request elements URL, as nextUrlin each standby mode, you can check if it is nextUrlnull or not condition else, if null means there are no more elements available.

Finally, listen again to ListView:

yourListView.setOnScrollListener(scrollListener);