前几篇文章介绍了Listview，但在实际开发中也经常会用到多层的Listview来展示数据，比如qq中的好友展示，所以这张来了解一下ExpandableListview，基本思想与Listview大致是相同的，所以用起来会比较方便。

实现效果图：

程序代码：

布局文件：

activity_main.xml：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <ExpandableListView
        android:id="@+id/expandableListView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" >
    </ExpandableListView>

</RelativeLayout>

list_item:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >


    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />


</RelativeLayout>

package com.listviewdemo_expandablelistview;

import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.os.Bundle;
import android.widget.ExpandableListView;

public class MainActivity extends Activity {
	private ExpandableListView listView;
	private List<String> group;
	private List<List<String>> child;
	private MyAdapter adapter;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		listView = (ExpandableListView) findViewById(R.id.expandableListView);
		/**
		 * 初始化数据 
		 */
		initData();
		adapter = new MyAdapter(this,group,child);
		listView.setAdapter(adapter);
		
	}

	private void initData() {
		group = new ArrayList<String>();
		child = new ArrayList<List<String>>();
		addInfo("北京",new String[]{"朝阳","海淀","东城区","西城区"});
		addInfo("河北", new String[]{"邯郸","石家庄","邢台"});
		addInfo("广东", new String[]{"广州","深圳","珠海"});
	}
	
	/**
	 * 添加数据信息
	 * @param g
	 * @param c
	 */
	private void addInfo(String g,String[] c) {
		group.add(g);
		List<String> list = new ArrayList<String>();
		for (int i = 0; i < c.length; i++) {
			list.add(c[i]);
		}
		child.add(list);
	}

}

package com.listviewdemo_expandablelistview;

import java.util.List;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;
/**
 * expandableListView适配器
 *
 */
public class MyAdapter extends BaseExpandableListAdapter {
	private Context context;
	private List<String> group;
	private List<List<String>> child;

	public MyAdapter(Context context, List<String> group,
			List<List<String>> child) {
		this.context = context;
		this.group = group;
		this.child = child;
	}

	@Override
	public int getGroupCount() {
		return group.size();
	}

	@Override
	public int getChildrenCount(int groupPosition) {
		return child.size();
	}

	@Override
	public Object getGroup(int groupPosition) {
		return group.get(groupPosition);
	}

	@Override
	public Object getChild(int groupPosition, int childPosition) {
		return child.get(childPosition).get(childPosition);
	}

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

	@Override
	public long getChildId(int groupPosition, int childPosition) {
		return childPosition;
	}

	@Override
	public boolean hasStableIds() {
		return false;
	}
	
	/**
	 * 显示：group
	 */
	@Override
	public View getGroupView(int groupPosition, boolean isExpanded,
			View convertView, ViewGroup parent) {
		ViewHolder holder;
		if (convertView == null) {
			convertView = LayoutInflater.from(context).inflate(
					R.layout.list_item, null);
			holder = new ViewHolder();
			holder.textView = (TextView) convertView
					.findViewById(R.id.textView);
			convertView.setTag(holder);
		} else {
			holder = (ViewHolder) convertView.getTag();
		}
		holder.textView.setText(group.get(groupPosition));
		holder.textView.setTextSize(25);
		holder.textView.setPadding(36, 10, 0, 10);
		return convertView;

	}
	
	/**
	 * 显示：child
	 */
	@Override
	public View getChildView(int groupPosition, int childPosition,
			boolean isLastChild, View convertView, ViewGroup parent) {
		ViewHolder holder;
		if (convertView == null) {
			convertView = LayoutInflater.from(context).inflate(
					R.layout.list_item, null);
			holder = new ViewHolder();
			holder.textView = (TextView) convertView
					.findViewById(R.id.textView);
			convertView.setTag(holder);
		} else {
			holder = (ViewHolder) convertView.getTag();
		}
		holder.textView.setText(child.get(groupPosition).get(childPosition));
		holder.textView.setTextSize(20);
		holder.textView.setPadding(72, 10, 0, 10);
		return convertView;
	}

	class ViewHolder {
		TextView textView;
	}

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

}