先看效果图:

要实现这个效果，activity必须实现ExpandableListActivity

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		requestWindowFeature(Window.FEATURE_NO_TITLE);
		setContentView(R.layout.main);
		mContactListView = getExpandableListView();
		mContactListView.setBackgroundResource(R.drawable.default_bg);
		registerForContextMenu(mContactListView);
		mContactDataBase = ((ContactApplication) getApplication())
				.getmContactDataBase();

		getExpandableListView().setCacheColorHint(0);// 拖动时避免出现黑色
		getExpandableListView().setDivider(null);// 去掉每项下面的黑线(分割线)
		// 自定义下拉图标
		getExpandableListView().setGroupIndicator(
				getResources().getDrawable(R.drawable.expander_ic_folder));
		setAdatperForExpandableListView();
	}

	/**
	 * 设置ExpandableListView的adapter
	 */
	private void setAdatperForExpandableListView() {
		Cursor groupCursor = mContactDataBase.getAllGroups();  //这个是从数据库里查询出所有的组
		Util.d(TAG, "groupCursor=" + groupCursor);
		// curosr的生命周期将和activity有关
		startManagingCursor(groupCursor);

		// set my adapter
		<strong>ContactTreeAdapter </strong>contactTreeAdapter = new ContactTreeAdapter(
				groupCursor, this, true, mContactDataBase);
		setListAdapter(contactTreeAdapter);
	}

public class ContactTreeAdapter extends CursorTreeAdapter {

	/** log tag. */
	private static final String TAG = "ContactTreeAdapter";

	/** context */
	public Context mContext = null;
	private Cursor mCursor = null;

	private ContactDataBase mContactDataBase;

	// contact表字段索引
	private static final int INDEX_NAME = 1;
	private static final int INDEX_PHONENUMBER = 2;

	// group表字段索引
	private static final int INDEX_GROUPNAME = 1;

	public ContactTreeAdapter(Cursor cursor, Context context,
			boolean autoRequery, ContactDataBase contactDataBase) {
		super(cursor, context, autoRequery);
		mContext = context;
		this.mContactDataBase = contactDataBase;
		// TODO Auto-generated constructor stub
	}

	@Override
	protected Cursor getChildrenCursor(Cursor groupCursor) {
		// TODO Auto-generated method stub
		String groupName = groupCursor.getString(INDEX_GROUPNAME);// 得到当前的组名
		Cursor childCursor = mContactDataBase.getContactsByGroupName(groupName);
		return childCursor;
	}

	@Override
	protected View newGroupView(Context context, Cursor cursor,
			boolean isExpanded, ViewGroup parent) {
		// TODO Auto-generated method stub
		Util.d(TAG, "newGroupView");
		LayoutInflater inflate = LayoutInflater.from(mContext);
		View view = inflate.inflate(R.layout.grouplayout, null);
		bindGroupView(view, context, cursor, isExpanded);
		return view;

	}

	@Override
	protected void bindGroupView(View view, Context context, Cursor cursor,
			boolean isExpanded) {
		// TODO Auto-generated method stub
		Util.d(TAG, "bindGroupView");
		TextView groupName = (TextView) view.findViewById(R.id.groupName);
		String group = cursor.getString(INDEX_GROUPNAME);
		groupName.setText(group);

		TextView groupCount = (TextView) view.findViewById(R.id.groupCount);
		int count = mContactDataBase.getCountContactByGroupName(group);
		Util.d(TAG, "count=" + count + "group=" + group);
		groupCount.setText("[" + count + "]");
	}

	@Override
	protected View newChildView(Context context, Cursor cursor,
			boolean isLastChild, ViewGroup parent) {
		// TODO Auto-generated method stub
		Util.d(TAG, "newChildView");
		LayoutInflater inflate = LayoutInflater.from(mContext);
		View view = inflate.inflate(R.layout.childlayout, null);
		bindChildView(view, context, cursor, isLastChild);
		return view;
	}

	@Override
	protected void bindChildView(View view, Context context, Cursor cursor,
			boolean isLastChild) {
		// TODO Auto-generated method stub
		Util.d(TAG, "bindChildView cursor.getString(INDEX_PHONENUMBER)="
				+ cursor.getString(INDEX_PHONENUMBER));
		TextView name = (TextView) view.findViewById(R.id.name);
		name.setText(cursor.getString(INDEX_NAME));

		TextView description = (TextView) view.findViewById(R.id.description);
		description.setTextKeepState(cursor.getString(INDEX_PHONENUMBER));
	}

}<strong>
</strong>

代码可以在http://download.csdn.net/detail/baidu_nod/7684649下载