Data is not displayed in the ListView but if it is seen that it is full

public class FillList extends AsyncTask<String, String, String> {
        String z = "";
        ListView lstpoints = (ListView) findViewById(R.id.lstpoints);
        List<Map<String, String>> pointslist  = new ArrayList<Map<String, String>>();

        @Override
        protected void onPreExecute() {
            pbbar.setVisibility(View.VISIBLE);
        }

        @Override
        protected void onPostExecute(String r) {

            pbbar.setVisibility(View.GONE);
            Toast.makeText(MapsPreviosProductor.this, r, Toast.LENGTH_SHORT).show();

            String[] from = { "_id", "Latitud", "Longitud"};
            int[] views = { R.id.lblidpunprepro, R.id.lbllatprepro, R.id.lbllonprepro};
            final SimpleAdapter ADA = new SimpleAdapter(MapsPreviosProductor.this,  pointslist, R.layout.lstpunpreproii, from,  views);

            lstpoints.setAdapter(ADA);

            lstpoints.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
                    HashMap<String, Object> obj = (HashMap<String, Object>) ADA.getItem(arg2);
                    idpoint = (String) obj.get("A");
                    String latitud = (String) obj.get("B");
                    String longitud = (String) obj.get("C");
                    txtlatitud.setText(latitud);
                    txtlongitud.setText(longitud);
                }
            });
        }

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

            try {
                SQLiteDatabase db = openOrCreateDatabase("SAICoffeeSQL", MODE_PRIVATE, null);
                if (db == null) {
                    z = "Error al conectar con la base de datos";
                } else {
                    String query = "select _id, Latitud, Longitud from TB_previos_productor";
                    Cursor ps = db.rawQuery(query, null);
                    //ArrayList<String> data1 = new ArrayList<String>();
                    ps.moveToFirst();
                    while (ps.moveToNext()){
                       Map<String, String> datanum = new HashMap<String, String>();
                       datanum.put("A", ps.getString(ps.getColumnIndex("_id")));
                       datanum.put("B", ps.getString(ps.getColumnIndex("Latitud")));
                       datanum.put("C", ps.getString(ps.getColumnIndex("Longitud")));
                      pointslist.add(datanum);
                   }
                    z = "Consulta exitosa";
                    db.close();
                    ps.close();
                }
            } catch (Exception ex) {
                z = "Error al obtener los valores de las tabla";
            }
            return z;
        }
    }