滚动到达结束时如何在android expandable listview中使用Loadmore数据

Question

I am creating an android application in which i have used expandable listview in which i would like to set a limit to show only 10 datas at first in the expandable listview.once the listview reaches end it will load another 10 datas from the database for which the loading the data for group works fine but for the child view it is not working properly can any one tell me how to make the childview to show the loaded item in the expandable listview.

Background process which loads data:

private class LoadDataTask extends AsyncTask<Void, Void, Void> {
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        loadingMore = true;
        // showDialog(progress_bar_type);
    }

    @Override
    protected Void doInBackground(Void... params) {

        if (isCancelled()) {
            return null;
        }
        Log.e("test2", "reached");
        // Simulates a background task
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
        }


        Log.e("test3", "starting");
        databasehandler = new DatabaseHandler(getApplicationContext());
        if (olimit > totalcount) {
            // olimit = 1;
            // olimit = 2;
        } else {
            olimit = olimit + 10;


        }
        listDataHeader = new ArrayList<String>();
        databasehandler = new DatabaseHandler(getApplicationContext());

        listDataHeader = new ArrayList<String>();
        String selectquery = "SELECT date,IFNULL(SUM(amountin),0) as amountin,IFNULL(SUM(amountout),0),daybookusertype as amountout FROM daybookdetails GROUP BY strftime('%Y-%m-%d',date) ORDER BY strftime('%Y-%m-%d',date) DESC LIMIT '" + olimit + "'";
        SQLiteDatabase db = databasehandler.getReadableDatabase();
        Cursor cursor = db.rawQuery(selectquery, null);
        if (cursor.moveToFirst()) {
            do {
                loadeddate = cursor.getString(0);

                String s = loadeddate;
                String[] spiliter = s.split("-");
                String year = spiliter[0];
                String month = spiliter[1];
                String dates = spiliter[2];
                if (month.startsWith("01")) {
                    disorderedlist = dates + "Jan" + year;
                    disorderedlist = disorderedlist.replaceAll("\\s+", "");
                } else if (month.startsWith("02")) {
                    disorderedlist = dates + "Feb" + year;
                    disorderedlist = disorderedlist.replaceAll("\\s+", "");
                } else if (month.startsWith("03")) {
                    disorderedlist = dates + "Mar" + year;
                    disorderedlist = disorderedlist.replaceAll("\\s+", "");
                } else if (month.startsWith("04")) {
                    disorderedlist = dates + "Apr" + year;
                    disorderedlist = disorderedlist.replaceAll("\\s+", "");
                } else if (month.startsWith("05")) {
                    disorderedlist = dates + "May" + year;
                    disorderedlist = disorderedlist.replaceAll("\\s+", "");
                } else if (month.startsWith("06")) {
                    disorderedlist = dates + "Jun" + year;
                    disorderedlist = disorderedlist.replaceAll("\\s+", "");
                } else if (month.startsWith("07")) {
                    disorderedlist = dates + "Jul" + year;
                    disorderedlist = disorderedlist.replaceAll("\\s+", "");
                } else if (month.startsWith("08")) {
                    disorderedlist = dates + "Aug" + year;
                    disorderedlist = disorderedlist.replaceAll("\\s+", "");
                } else if (month.startsWith("09")) {
                    disorderedlist = dates + "Sep" + year;
                    disorderedlist = disorderedlist.replaceAll("\\s+", "");
                } else if (month.startsWith("10")) {
                    disorderedlist = dates + "Oct" + year;
                    disorderedlist = disorderedlist.replaceAll("\\s+", "");
                } else if (month.startsWith("11")) {
                    disorderedlist = dates + "Nov" + year;
                    disorderedlist = disorderedlist.replaceAll("\\s+", "");
                } else if (month.startsWith("12")) {
                    disorderedlist = dates + "Dec" + year;
                    disorderedlist = disorderedlist.replaceAll("\\s+", "");
                }
                listDataHeader.add(disorderedlist);
                chid = new ArrayList<Daybooklist>();
                daybooklists = databaseHandler.getAllDaywisedaybookdetails(loadeddate);
                for (int j = 0; j < daybooklists.size(); j++) {
                    String name = daybooklists.get(j).getName();
                    String desc = daybooklists.get(j).getDescription();
                    String type = daybooklists.get(j).getType();
                    String usertype = daybooklists.get(j).getUsertype();
                    String amtin = daybooklists.get(j).getAmountin();
                    String amtout = daybooklists.get(j).getAmountout();
                    String extamt = daybooklists.get(j).getExtraamt();
                    String mobno = daybooklists.get(j).getMobileno();
                    String datess = daybooklists.get(j).getSdate();
                    String time = daybooklists.get(j).getCtime();
                    Log.e("ctime", time);
                    chid.add(new Daybooklist(name, desc, type, usertype, amtin, amtout, extamt, mobno, datess, time));
                }

                listDataChild.put(String.valueOf(listDataHeader), chid);

            } while (cursor.moveToNext());

        }
        cursor.close();
        db.close();


        return null;

    }

    @Override
    protected void onPostExecute(Void result) {

        listAdapter.setTransactionList(listDataHeader, listDataChild);


        loadingMore = false;
        //  dismissDialog(progress_bar_type);

        super.onPostExecute(result);
    }

    @Override
    protected void onCancelled() {
        // Notify the loading more operation has finished
        loadingMore = false;
    }
}

Expandable ListAdapter:

public class DaybookExpandableAdapter extends BaseExpandableListAdapter {
String updatedate = "";
private Context _context;
private List<String> _listDataHeader; // header titles
// child data in format of header title, child title
private HashMap<String, List<Daybooklist>> _listDataChild;
private DatabaseHandler databaseHandler;
boolean isListScrolling;

public DaybookExpandableAdapter(Context context, List<String> listDataHeader,
                                HashMap<String, List<Daybooklist>> listChildData) {
    this._context = context;
    this._listDataHeader = listDataHeader;
    this._listDataChild = listChildData;
}

@Override
public Object getChild(int groupPosition, int childPosititon) {
    return this._listDataChild.get(this._listDataHeader.get(groupPosition))
            .get(childPosititon);
}

@Override
public long getChildId(int groupPosition, int childPosition) {
    return childPosition;
}

@Override
public View getChildView(int groupPosition, final int childPosition,
                         boolean isLastChild, View convertView, ViewGroup parent) {

    /*final String childText = (String) getChild(groupPosition, childPosition);
    final String childtime = (String) getChild(groupPosition,childPosition);*/
    Daybooklist daybooklist = (Daybooklist) getChild(groupPosition, childPosition);
    if (convertView == null) {
        LayoutInflater infalInflater = (LayoutInflater) this._context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = infalInflater.inflate(R.layout.model_daybook_listitem, null);
    }

    TextView txtname = (TextView) convertView.findViewById(R.id.tv_daybook_name);
    TextView txttime = (TextView) convertView.findViewById(R.id.tv_daybook_time);
    TextView day_name = (TextView) convertView.findViewById(R.id.tv_daybook_name);
    TextView day_description = (TextView) convertView.findViewById(R.id.tv_daybook_description);
    TextView day_type = (TextView) convertView.findViewById(R.id.tv_daybook_type);
    TextView day_amount = (TextView) convertView.findViewById(R.id.tv_daybook_amount);
    TextView day_usertype = (TextView) convertView.findViewById(R.id.tv_usertype);
    TextView day_time = (TextView) convertView.findViewById(R.id.tv_daybook_time);
    ImageView day_check = (ImageView) convertView.findViewById(R.id.img_doneall);
    TextView daybook_location = (TextView) convertView.findViewById(R.id.tv_daybook_location);


    txtname.setText(daybooklist.getName());
    txttime.setText(daybooklist.getCtime());
    databaseHandler = new DatabaseHandler(_context);
    if (daybooklist.getUsertype() != null && !daybooklist.getUsertype().isEmpty()) {
        if (daybooklist.getUsertype().startsWith("farmer") | daybooklist.getUsertype().startsWith("singleworker") | daybooklist.getUsertype().startsWith("groupworker") | daybooklist.getUsertype().startsWith("payvehicle")) {
            if (daybooklist.getUsertype().startsWith("farmer")) {
                day_name.setText(daybooklist.getName());
                day_description.setText(daybooklist.getDescription());
                String mobno = daybooklist.getMobileno();
                Log.e("mobno", mobno);
                String locat = String.valueOf(databaseHandler.getfarmerlocation(mobno));
                locat = locat.replaceAll("\\[", "").replaceAll("\\]", "");
                Log.e("farmerlocation", locat);
                daybook_location.setText(locat);
                day_type.setText(daybooklist.getType());
                if (daybooklist.getName() != null && daybooklist.getName().startsWith("no")) {
                    day_name.setText(" ");
                } else if (daybooklist.getDescription() != null && daybooklist.getDescription().startsWith("no")) {
                    day_description.setText(" ");
                }

                day_amount.setText("\u20B9" + daybooklist.getExtraamt());
                if (daybooklist.getAmountout().startsWith("0.0") | daybooklist.getAmountout().startsWith("0")) {
                    //     day_amount.setTextColor(activity.getResources().getColor(R.color.green));
                    Log.e("Amountout", daybooklist.getAmountout());
                    day_check.setVisibility(View.INVISIBLE);
                } else {
                    //    day_amount.setTextColor(activity.getResources().getColor(R.color.album_title));
                    Log.e("Amountout", daybooklist.getAmountout());
                    day_check.setVisibility(View.VISIBLE);
                }

                day_time.setText(daybooklist.getCtime());
            } else {
                day_name.setText(daybooklist.getName());
                day_description.setText(daybooklist.getDescription());
                daybook_location.setText(daybooklist.getType());
                day_type.setText(daybooklist.getType());
                if (daybooklist.getName() != null && daybooklist.getName().startsWith("no")) {
                    day_name.setText(" ");
                } else if (daybooklist.getDescription() != null && daybooklist.getDescription().startsWith("no")) {
                    day_description.setText(" ");
                }

                day_amount.setText("\u20B9" + daybooklist.getExtraamt());
                if (daybooklist.getAmountout().startsWith("0.0") | daybooklist.getAmountout().startsWith("0")) {
                    //  day_amount.setTextColor(activity.getResources().getColor(R.color.green));
                    Log.e("Amountout", daybooklist.getAmountout());
                    day_check.setVisibility(View.INVISIBLE);
                } else {
                    //  day_amount.setTextColor(activity.getResources().getColor(R.color.album_title));
                    Log.e("Amountout", daybooklist.getAmountout());
                    day_check.setVisibility(View.VISIBLE);
                }

                day_time.setText(daybooklist.getCtime());
            }


        } else if (daybooklist.getUsertype().startsWith("advancefarmer") | daybooklist.getUsertype().startsWith("workeradvance") | daybooklist.getUsertype().startsWith("kgroupadvance") | daybooklist.getUsertype().startsWith("otherexpense") | daybooklist.getUsertype().startsWith("vehicle")) {
            if (daybooklist.getUsertype().startsWith("advancefarmer")) {
                day_name.setText(daybooklist.getName());
                day_description.setText(daybooklist.getDescription());
                day_type.setText(daybooklist.getType());
                String mobno = daybooklist.getMobileno();
                Log.e("mobno", mobno);
                String locat = String.valueOf(databaseHandler.getfarmerlocation(mobno));
                locat = locat.replaceAll("\\[", "").replaceAll("\\]", "");
                Log.e("farmerlocation", locat);
                daybook_location.setText(locat);
                if (daybooklist.getName() != null && daybooklist.getName().startsWith("no")) {
                    day_name.setText(" ");
                } else if (daybooklist.getDescription() != null && daybooklist.getDescription().startsWith("no")) {
                    day_description.setText(" ");
                }
                Log.e("amountout", daybooklist.getAmountout());
                day_amount.setText("\u20B9" + daybooklist.getAmountout());
                day_time.setText(daybooklist.getCtime());
            } else {
                day_name.setText(daybooklist.getName());
                day_description.setText(daybooklist.getType());
                day_type.setText(daybooklist.getType());
                daybook_location.setText(daybooklist.getDescription());
                if (daybooklist.getName() != null && daybooklist.getName().startsWith("no")) {
                    day_name.setText(" ");
                } else if (daybooklist.getDescription() != null && daybooklist.getDescription().startsWith("no")) {
                    day_description.setText(" ");
                }
                Log.e("amountout", daybooklist.getAmountout());
                day_amount.setText("\u20B9" + daybooklist.getAmountout());
                day_time.setText(daybooklist.getCtime());
            }


        } else if (daybooklist.getUsertype().startsWith("buyer")) {
            day_name.setText(daybooklist.getName());
            day_description.setText(daybooklist.getDescription());
            day_amount.setText("\u20B9" + daybooklist.getAmountin());
            day_type.setText(" ");
            day_time.setText(daybooklist.getCtime());
            daybook_location.setText(daybooklist.getType());
        }
        if (daybooklist.getUsertype().startsWith("farmer")) {
            day_usertype.setText("F");
            day_usertype.setBackgroundResource(R.drawable.textview_farmer);
        } else if (daybooklist.getUsertype().startsWith("advancefarmer")) {
            day_usertype.setText("FA");
            day_usertype.setBackgroundResource(R.drawable.textview_farmer);
        } else if (daybooklist.getUsertype().startsWith("singleworker")) {
            day_usertype.setText("W");
            day_usertype.setBackgroundResource(R.drawable.textview_worker);
        } else if (daybooklist.getUsertype().startsWith("workeradvance")) {
            day_usertype.setText("WA");
            day_usertype.setBackgroundResource(R.drawable.textview_worker);
        } else if (daybooklist.getUsertype().startsWith("groupworker")) {
            day_usertype.setText("G");
            day_usertype.setBackgroundResource(R.drawable.textview_worker);
        } else if (daybooklist.getUsertype().startsWith("kgroupadvance")) {
            day_usertype.setText("GA");
            day_usertype.setBackgroundResource(R.drawable.textview_worker);
        } else if (daybooklist.getUsertype().startsWith("otherexpense")) {
            day_usertype.setText("E");
            day_usertype.setBackgroundResource(R.drawable.textview_otherexpense);
        } else if (daybooklist.getUsertype().startsWith("vehicle")) {
            day_usertype.setText("V");
            day_usertype.setBackgroundResource(R.drawable.textview_vehicle);
        } else if (daybooklist.getUsertype().startsWith("gsalary")) {
            day_usertype.setText("GS");
            day_usertype.setBackgroundResource(R.drawable.textview_worker);
        } else if (daybooklist.getUsertype().startsWith("isalary")) {
            day_usertype.setText("WS");
            day_usertype.setBackgroundResource(R.drawable.textview_worker);
        } else if (daybooklist.getUsertype().startsWith("payvehicle")) {
            day_usertype.setText("VP");
            day_usertype.setBackgroundResource(R.drawable.textview_vehicle);
        } else if (daybooklist.getUsertype().startsWith("buyer")) {
            day_usertype.setText("B");
            day_usertype.setBackgroundResource(R.drawable.textview_buyer);
        }
    }


    return convertView;
}

@Override
public int getChildrenCount(int groupPosition) {
    return this._listDataChild.get(this._listDataHeader.get(groupPosition))
            .size();
}

@Override
public Object getGroup(int groupPosition) {
    return this._listDataHeader.get(groupPosition);
}

@Override
public int getGroupCount() {
    return this._listDataHeader.size();
}

@Override
public long getGroupId(int groupPosition) {
    return groupPosition;
}

@Override
public View getGroupView(int groupPosition, boolean isExpanded,
                         View convertView, ViewGroup parent) {
    final String headerTitle = (String) getGroup(groupPosition);

    if (convertView == null) {
        LayoutInflater infalInflater = (LayoutInflater) this._context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = infalInflater.inflate(R.layout.model_daybook_group, null);
    }

    TextView lblListHeader = (TextView) convertView
            .findViewById(R.id.tv_daybook_date);
    final ImageView img_pdg = (ImageView) convertView.findViewById(R.id.img_printpdf);

    lblListHeader.setTypeface(null, Typeface.BOLD);
    lblListHeader.setText(headerTitle);
    String strDate = headerTitle;
    SimpleDateFormat dateFormat = new SimpleDateFormat("ddMMMyyyy");
    try {
        Date varDate = dateFormat.parse(strDate);
        dateFormat = new SimpleDateFormat("yyyy-MM-dd");
        updatedate = dateFormat.format(varDate);

    } catch (Exception e) {
        // TODO: handle exception
        e.printStackTrace();
    }
    img_pdg.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View view, MotionEvent motionEvent) {
            switch (motionEvent.getAction()) {
                case MotionEvent.ACTION_DOWN:
                    img_pdg.setColorFilter(ContextCompat.getColor(_context, R.color.colorAccent));

                    break;
                case MotionEvent.ACTION_UP:
                    img_pdg.clearColorFilter();
                    AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(
                            _context);

                    // set title
                    alertDialogBuilder.setTitle(R.string.app_name);

                    // set dialog message
                    alertDialogBuilder
                            .setMessage(_context.getResources().getString(R.string.daybookreport) + headerTitle)
                            .setCancelable(true)
                            .setPositiveButton(R.string.yes, new DialogInterface.OnClickListener() {
                                public void onClick(DialogInterface dialog, int id) {
                                    // if this button is clicked, close
                                    // current activity
                                    Intent pdfreport = new Intent(_context, Activity_Daybookpdf.class);
                                    pdfreport.putExtra("date", updatedate);
                                    _context.startActivity(pdfreport);
                                }
                            })
                            .setNegativeButton(R.string.no, new DialogInterface.OnClickListener() {
                                public void onClick(DialogInterface dialog, int id) {
                                    // if this button is clicked, just close
                                    // the dialog box and do nothing
                                    dialog.cancel();
                                }
                            });

                    // create alert dialog
                    AlertDialog alertDialog = alertDialogBuilder.create();

                    // show it
                    alertDialog.show();
                    Button nbutton = alertDialog.getButton(DialogInterface.BUTTON_NEGATIVE);
                    nbutton.setTextColor(_context.getResources().getColor(R.color.colorAccent));
                    Button pbutton = alertDialog.getButton(DialogInterface.BUTTON_POSITIVE);
                    pbutton.setBackgroundColor(_context.getResources().getColor(R.color.colorAccent));
                    pbutton.setPadding(0, 10, 10, 0);
                    pbutton.setTextColor(Color.WHITE);
                    break;
            }
            return true;


        }
    });
    return convertView;
}

@Override
public boolean hasStableIds() {
    return false;
}

@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
    return true;
}

public void setTransactionList(List<String> newList, HashMap<String, List<Daybooklist>> childlist) {
    _listDataHeader = newList;
    _listDataChild = childlist;

    notifyDataSetChanged();
}



public void isScrolling(boolean isScroll) {
    isListScrolling = isScroll;
    Log.e("scrollcheck", String.valueOf(isListScrolling));
}

}

Problem:

  listDataChild.put(String.valueOf(listDataHeader), chid);

can anyone tell me what i have to change over here

Answer 1

try this may help you :

1. at first define this variable to save states :

     private boolean loadMore = true; private int pastVisiblesItems, visibleItemCount, totalItemCount; 

2. then set scroll listener for listView :

     listView.setOnScrollListener(new AbsListView.OnScrollListener() { @Override public void onScrollStateChanged(AbsListView absListView, int i) { } @Override public void onScroll(AbsListView absListView, int i, int i1, int i2) { visibleItemCount = listView.getChildCount(); totalItemCount = listView.getCheckedItemCount(); pastVisiblesItems = listView.getFirstVisiblePosition(); if (loadMore) { if ((visibleItemCount + pastVisiblesItems) >= totalItemCount) { soundListSearch.add(null); new LoadDataTask().execute(); } } } }); 

3. And finally loadMore=false ever that you want to prevent load more data(for example when catch exception in AsyncTask or data query ended or....)

---

Edit 1 for adding to listDataChild HashMap

no , it's not correct. you should use like this

  listDataChild.put(listDataHeader.get(position), chid); 

because first value of listDataChild should be string type but you try set a arrayList

for add all items of listDataChild into listDataChild do this :

  for (int i =0 ; i<listDataHeader.size();i++)
    {
         listDataChild.put(listDataHeader.get(i), chid); 
    }