Android : ExpandableListView shows only first parentlist not child of it in android

I want to create an Expandable-List-view inside tab fragment programmatically. So i tried an example from here [enter link description here][1]

[1]: http://www.androidhive.info/2013/07/android-expandable-list-view-tutorial/ know the problem is I am getting only one list with no child-list and I am trying to create 3 Expandable-list-view here the code for creating list

public class FormFragment extends Fragment implements OnMenuItemClickListener{
ExpandableListAdapter adapter;
List<String> listDataHeader;
HashMap<String, List<String>> listDataChild; 
String editview = "";
App app;
public View onCreateView(final LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) 
{
    app = (App) getActivity().getApplication();
view = new LinearLayout(getActivity());
    view.setOrientation(LinearLayout.VERTICAL);
LinearLayout listlayout = new LinearLayout(getActivity());
listlayout.setOrientation(LinearLayout.VERTICAL);
    ExpandableListView listitem = new ExpandableListView(getActivity());
    prepareListData();
    adapter = new ExpandableListAdapter(getActivity(),listDataHeader, listDataChild);
    listitem.setAdapter(adapter);
    listlayout.addView(listitem);

 view.addView(listlayout);
}
private void prepareListData() {
    listDataHeader = new ArrayList<String>();
    listDataChild = new HashMap<String, List<String>>();

    // Adding child data
    listDataHeader.add("Top 250");
    listDataHeader.add("Now Showing");
    listDataHeader.add("Coming Soon..");

    // Adding child data
    List<String> top250 = new ArrayList<String>();
    top250.add("The Shawshank Redemption");
    top250.add("The Godfather");
    top250.add("The Godfather: Part II");
    top250.add("Pulp Fiction");
    top250.add("The Good, the Bad and the Ugly");
    top250.add("The Dark Knight");
    top250.add("12 Angry Men");

    List<String> nowShowing = new ArrayList<String>();
    nowShowing.add("The Conjuring");
    nowShowing.add("Despicable Me 2");
    nowShowing.add("Turbo");
    nowShowing.add("Grown Ups 2");
    nowShowing.add("Red 2");
    nowShowing.add("The Wolverine");

    List<String> comingSoon = new ArrayList<String>();
    comingSoon.add("2 Guns");
    comingSoon.add("The Smurfs 2");
    comingSoon.add("The Spectacular Now");
    comingSoon.add("The Canyons");
    comingSoon.add("Europa Report");

    listDataChild.put(listDataHeader.get(0), top250); // Header, Child data
    listDataChild.put(listDataHeader.get(1), nowShowing);
    listDataChild.put(listDataHeader.get(2), comingSoon);
}}

Here is ExpandableListAdapter.java

import java.util.HashMap;
import java.util.List;
import com.zekisolutions.bpscrm.App;
import com.zekisolutions.bpscrm.R;
import android.content.Context;
import android.graphics.Typeface;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;

public class ExpandableListAdapter extends BaseExpandableListAdapter {

private Context _context;
private List<String> _listDataHeader; // header titles
// child data in format of header title, child title
App a;
private  HashMap<String, List<String>>  _listDataChild;

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

public ExpandableListAdapter(App app) {
    // TODO Auto-generated constructor stub
    this.a = app;
}

@Override
public Object getChild(int groupPosition, int childPosititon) {
    System.out.println("value in groupPosition "+groupPosition);
    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);

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

    TextView txtListChild = (TextView) convertView
            .findViewById(R.id.grp_child);

    txtListChild.setText(childText);
    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()-1;
}

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

@Override
public View getGroupView(int groupPosition, boolean isExpanded,
        View convertView, ViewGroup parent) {
    String headerTitle = (String) getGroup(groupPosition);
    if (convertView == null) {
        LayoutInflater infalInflater = (LayoutInflater) this._context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = infalInflater.inflate(R.layout.parentrow, null);
    }

    TextView lblListHeader = (TextView) convertView
            .findViewById(R.id.parentList);
    lblListHeader.setTypeface(null, Typeface.BOLD);
    lblListHeader.setText(headerTitle);

    return convertView;
}

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

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

help me to find the issue. Any Idea is appreciated.

Thanks in Advance.