アンドロイドのfragmentにアイテムを表示したいが上手くいかない

http://gacken.com/wp/program/android/1927/
を参考にアンドロイドのフラグメントにアダプターを入れて表示させたのですが
１　２　３は表示されるのですがグループは表示されません。
どのようにすれば解決するのでしょうか。

ItemListFragment.java

public class ItemListFragment extends ListFragment {

private Callbacks mCallbacks = sDummyCallbacks;
public class GroupSpinnerItem {
    public boolean isGroup;        // グループフラグ
    public String itemName;        // アイテム名

    public GroupSpinnerItem(boolean isGroup, String itemName) {
        this.isGroup = isGroup;
        this.itemName = itemName;
    }
}

public interface Callbacks {

    void onItemSelected(String id);
}

private static Callbacks sDummyCallbacks = new Callbacks() {
    @Override
    public void onItemSelected(String id) {
    }
};

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

        GroupSpinnerAdapter adapter = new GroupSpinnerAdapter(getContext());

            adapter.addItem(new GroupSpinnerItem(true, "グループ"));
            adapter.addItem(new GroupSpinnerItem(false, "１"));
            adapter.addItem(new GroupSpinnerItem(false, "２"));
            adapter.addItem(new GroupSpinnerItem(false, "３"));
            setListAdapter(adapter);
            }

GroupSpinnerAdapter.java

public  class GroupSpinnerAdapter extends BaseAdapter {
public static ArrayList<ItemListFragment.GroupSpinnerItem> itemList = new ArrayList<ItemListFragment.GroupSpinnerItem>();
public static LayoutInflater inflater;
public GroupSpinnerAdapter(Context context) {
    inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public static void addItem(ItemListFragment.GroupSpinnerItem item) {
    itemList.add(item);
}
public int getCount() {
    return itemList.size();
}
public Object getItem(int position) {
    return itemList.get(position);
}
public long getItemId(int position) {
    return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
    return createView(position, convertView, parent, false);
}
@Override
public View getDropDownView(int position, View convertView,
            ViewGroup parent) {
    return createView(position, convertView, parent, true);
}
public View createView(int position, View convertView, ViewGroup parent, boolean isDropDown) {
    TextView tvName = null;
    if(convertView instanceof TextView) {
        tvName = (TextView)convertView;
    }
    if(tvName == null) {
        tvName = (TextView)inflater.inflate(android.R.layout.simple_spinner_item, parent, false);
    }
    ItemListFragment.GroupSpinnerItem item = itemList.get(position);
    if(item.isGroup) {
        if(isDropDown) {
            tvName.setTypeface(Typeface.create(Typeface.DEFAULT, Typeface.BOLD));
            tvName.setText(item.itemName);
            tvName.setBackgroundColor(Color.BLUE);
        }
    }
    else {
        String text = "  " + item.itemName;
        tvName.setText(text);
        tvName.setBackgroundColor(Color.TRANSPARENT);
    }
    return tvName;
}
@Override
public boolean isEnabled(int position) {
    return (itemList.get(position).isGroup == false);
}
}