androidjsonandroid-listviewendlessscroll

How to implement endless scrolling listview


I am creating an application in which I am parsing data using Json parsing. I've implemented listview and in my response i have totalpage and current page objects,

A new user will get items from the first page. While the user is scrolling through the listview, the list expands with items from the next page (and the next and the next etc.)

this is my response http://pastie.org/10259792

The following is code I've tried:

HomeFragment

public class HomeFragment extends Fragment {
// Listview Adapter
        ListViewAdapter adapters;

            // Connection detector
            ConnectionDetector cd;

            // Alert dialog manager
            AlertDialogManager alert = new AlertDialogManager();

            // Progress Dialog
            private ProgressDialog pDialog;

            // Creating JSON Parser object
            JSONparserr jsonParser = new JSONparserr();

            ArrayList<HashMap<String, String>> WebsiteList;

            // albums JSONArray
            JSONArray data = null;
            String link_url;

            ArrayList<HashMap<String, String>> arrayTemplist;

            private AutoCompleteTextView inputSearch;

            private ListView lv;

            private static final String URL_ALBUMS = "";

            private static final String WEBSITE_MENU_ID ="Brand_name";

            private static final String TAG_MATCH="data";
            //private static final String TAG_NAME="Brand_name";
            private static final String TAG_PROFILE="id";
            private static final String TAG_CAST="Company";

public HomeFragment(){}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.fragment_home, container, false);

    lv = (ListView)rootView.findViewById(R.id.listpehlu);


    cd = new ConnectionDetector(getActivity());


    WebsiteList = new ArrayList<HashMap<String, String>>();

 // Loading Albums JSON in Background Thread
 new LoadAlbums().execute();

    // get listview

    inputSearch = (AutoCompleteTextView)rootView.findViewById(R.id.autoCompleteTextViewhomefrag);

    inputSearch.addTextChangedListener(new TextWatcher() {


        @Override
        public void onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) {

            arrayTemplist= new ArrayList<HashMap<String,String>>();
            String searchString =inputSearch.getText().toString().toLowerCase();

            for (int i = 0; i < WebsiteList.size(); i++)
            {
                String currentString =WebsiteList.get(i).get(HomeFragment.this.WEBSITE_MENU_ID);
                if (currentString.toLowerCase().startsWith(searchString ))
                {
                    arrayTemplist.add(WebsiteList.get(i));
                }
            }

            for (int i = 0; i < arrayTemplist.size(); i++)
            {
                String currentstrin = arrayTemplist.get(i).get(HomeFragment.this.WEBSITE_MENU_ID);
                //Toast.makeText(getApplicationContext(), currentstrin, Toast.LENGTH_LONG).show();

            }
      SimpleAdapter adapters = new SimpleAdapter(getActivity(), arrayTemplist,R.layout.list_item_match, new String[] {WEBSITE_MENU_ID,TAG_CAST
            }, new int[] {
                    R.id.txtbrndnm,R.id.txtbrndcomp});
            lv.setAdapter(adapters);

        }

        @Override
        public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,
                int arg3) {
            // TODO Auto-generated method stub

        }

        @Override
        public void afterTextChanged(Editable arg0) {
            // TODO Auto-generated method stub                         
        }
    });


    lv.setOnItemClickListener(new android.widget.AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> arg0, View view, int position,
                long arg3) {


            Selected_Product_Listing tf = new Selected_Product_Listing();
             Bundle bundle = new Bundle();
             bundle.putString("prducts_name", WebsiteList.get(position).get((WEBSITE_MENU_ID)));
            // bundle.putString("prducts_name", aList.get(position).get(INTEREST_ACCEPT_NAME));
             tf.setArguments(bundle);
              FragmentManager fm = getFragmentManager();
              FragmentTransaction ft = fm.beginTransaction();
              ft.replace(R.id.frame_container, tf);
              ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
              ft.addToBackStack(null);
              ft.commit();

            // Toast.makeText(getActivity(),"lets"+ WebsiteList.get(position).get(convertToBase64(convertToBase64(WEBSITE_MENU_ID))), Toast.LENGTH_LONG).show();

        }
    });   

    lv.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)
        {

        }
        }
        });



    return rootView;
}

public String convertToBase64(String text) {
    byte[] data = null;
    try {
        data = text.getBytes("UTF-8");
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    }
    return Base64.encodeToString(data, Base64.DEFAULT);
}

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

    private JSONObject jsonObj;


    /**
     * Before starting background thread Show Progress Dialog
     * */
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(getActivity());
        pDialog.setMessage("Loading...");
        pDialog.setIndeterminate(true);
        pDialog.setIndeterminateDrawable(getResources().getDrawable(R.drawable.custom_progress));

        pDialog.setCancelable(false);
        pDialog.show();
    }
    protected String doInBackground(String... args) {
        // Building Parameters
        List<NameValuePair> params = new ArrayList<NameValuePair>();

        // getting JSON string from URL
        String json = jsonParser.makeHttpRequest(URL_ALBUMS, "GET",
                params);

        // Check your log cat for JSON reponse
        Log.d("Albums JSON: ", "> " + json);
        if (json != null) {
            try {
                jsonObj = new JSONObject(json);
                // Getting JSON Array node
                data = jsonObj.getJSONArray(TAG_MATCH);

                String totpage=jsonObj.getString("total_page");
                System.out.println("Total Page"+totpage);

                String curpage=jsonObj.getString("current_page");
                System.out.println("Total Page"+curpage);



                // looping through All Contacts
                for (int i = 0; i < data.length(); i++) {
                    JSONObject c = data.getJSONObject(i);
                    HashMap<String, String> map = new HashMap<String, String>();
                    map.put(WEBSITE_MENU_ID,c.getString(WEBSITE_MENU_ID));
                 map.put(TAG_PROFILE, c.getString(TAG_PROFILE));
                    map.put(TAG_CAST, c.getString(TAG_CAST));

                    WebsiteList.add(map);
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
        } else {
            Log.e("ServiceHandler", "Couldn't get any data from the url");
        }
       return null;
    }


    protected void onPostExecute(String file_url) {
        // dismiss the dialog after getting all albums
        pDialog.dismiss();
        // updating UI from Background Thread

                ListAdapter adapter = new SimpleAdapter(
                        getActivity(), WebsiteList,
                        R.layout.list_item_match, new String[] {WEBSITE_MENU_ID,TAG_CAST
                         }, new int[] {
                                R.id.txtbrndnm,R.id.txtbrndcomp});


               lv.setAdapter(adapter); 

            }


    }

EndlessAdapter

 public class EndLessAdapter extends ArrayAdapter<String> {

private Context context;
private List<String> items;
private int layoutId;

public EndLessAdapter(Context context, List<String> items, int LayoutId) {
    super(context,LayoutId,items);
    this.context = context;
    this.items = items;
    this.layoutId = LayoutId;
}

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

    if(convertView == null)
        convertView = ((LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE)).inflate(layoutId,parent,false);

    TextView tView = (TextView)convertView.findViewById(R.id.txt);
    tView.setText(items.get(position));

    return convertView;
}
 }

EndlessLisView

public class EndlessListView extends ListView implements OnScrollListener {

private Context context;
private View footer;
private boolean isLoading;
private EndLessListener listener;

private BaseAdapter  adapter;

public EndlessListView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);        
    this.setOnScrollListener(this);

    this.context = context;
}

public EndlessListView(Context context, AttributeSet attrs) {
    super(context, attrs);
    this.setOnScrollListener(this);

    this.context = context;
}

public EndlessListView(Context context) {
    super(context);     
    this.setOnScrollListener(this);

    this.context = context;
}

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

}   

//  4
public void addNewData() {
    this.removeFooterView(footer);
   //       adapter.addAll(products);

    adapter.notifyDataSetChanged();
    isLoading = false;
}
public void setLoading()
{
    isLoading = false;
}

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

    if(getAdapter() == null)
        return;

    if(getAdapter().getCount() == 0)
        return;

    int l = visibleItemCount + firstVisibleItem;
    System.out.println("List View Total Item Count = "+totalItemCount+" , l = "+l+", is_loading = "+isLoading);
    if(l >= totalItemCount && !isLoading){

        //  add footer layout
        this.addFooterView(footer);

        //  set progress boolean
        isLoading = true;
        System.out.println("$$$$$$$$$ call loaddata $$$$$$$$$$$");
        //  call interface method to load new data
        listener.loadData();
    }
}

//  Calling order from MainActivity
//  1
public void setLoadingView(int resId) {

    footer = ((LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE)).inflate(resId, null);      //      footer = (View)inflater.inflate(resId, null);
    this.addFooterView(footer);
    System.out.println("addfooter ====@@@@@@");
}   

//  2
public void setListener(EndLessListener listener) {
    this.listener = listener;
}   

//  3
public void setAdapter(BaseAdapter adapter) {       

    super.setAdapter(adapter);
    this.adapter = adapter;

    this.removeFooterView(footer);
}

public void removeFooter(){
    this.removeFooterView(footer);
}

}


Solution

  • you didn't use EndlessListView in your Fragment. As I looked your response, it includes pagination. So, you need to request with page number to use endless scroll.

    This is just flow for Endless Listview. If your code still doesn't work, I hope you can learn sample projects after read this messages. I added only parts you need. Thanks

    Endless scroll only shows limited data on listview. When user scroll down to bottom, it will get next limited data from server. So you need to add current_page paramater in your request. I don't know exactly your api.

    First, you need variable for current_page which initialize with 0

    You have to know when to stop. You response has total_page field for that. Save and add validation

    Then you need to know when to request next page. For that,you already have codes in onScroll within EndlessListView. That code calculate and tell when user scroll down to bottom and it called

    listener.loadData();
    

    to request new data. But you still need to add listener for that. You already have

    public void setListener(EndLessListener listener) {
        this.listener = listener;
    } 
    

    You need to create Interface with the name EndlessListener and implements in your fragment. EndlessListener Interface will include loadData() function that request to server. After that you need to add listener for the listview.

    endlessListView.setListener(this);