How to get an item from child in ExpandableListView?

I have onChildClick method on my application, this my code

public class listview extends ExpandableListActivity {

 private static final String NAME = "NAME";
 private static final String IS_EVEN = "IS_EVEN";
 private ExpandableListAdapter mAdapter;
 List<Map<String, String>> groupData = new ArrayList<Map<String, String>>();
 List<List<Map<String, String>>> childData = new ArrayList<List<Map<String, String>>>();
 InputStream is;
 boolean addState = true;
 boolean addCountry;
 HashMap<String, String> countryMap = new HashMap<String, String>();
 HashMap<String, String> stateMap = new HashMap<String, String>();
 int count = 0;
 int count1 = -1;
 int count2 = 0;
 List<String> stateCount = new ArrayList<String>();

 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  // Reading data from text file to inout stream
  is = this.getResources().openRawResource(R.raw.countrystate);
  BufferedReader reader = new BufferedReader(new InputStreamReader(is));
  try {
   String line = "";
   while ((line = reader.readLine()) != null) {
    String[] strings = line.split("-");
    String ctry = strings[0].trim();
    String st = strings[1].trim();
    /*
     * loading country and state to two separate hash tables
     */
    if (countryMap.containsValue(ctry)) {
     addCountry = false;
     if (!addState) {
      stateMap.put("state" + count1 + count2, st);
      count2++;
     }
    } else {
     addCountry = !addCountry;
     count1++;
     //adding no. of states for a country to a list
     stateCount.add("" + count2);
     if (addCountry) {
      count2 = 0;
      countryMap.put("country" + count, ctry);
      stateMap.put("state" + count1 + count2, st);
      addState = false;
     }
     count2++;
     count++;
    }
   }
  } catch (Exception e) {
  }
  //re-arranging the state count list
  stateCount.add("" + count2