可展开（收缩）的列表ListView(ExpandableListView)

1、首先创建我们的Activity，继承 android.app.ExpandableListActivity，直接看代码吧。

package com.ideasandroid.sample;import android.app.ExpandableListActivity;import android.os.Bundle;import com.ideasandroid.sample.adapter.IdeasExpandableListAdapter;/*** 可展开(收缩)列表示例*/public class IdeasExpandableListView extends ExpandableListActivity {@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);//设置列表适配器IdeasExpandableListAdaptersetListAdapter(new IdeasExpandableListAdapter(this));}}

2、创建适配器，继承android.widget.BaseExpandableListAdapter。

package com.ideasandroid.sample.adapter;import java.util.ArrayList;import java.util.List;import android.content.Context;import android.view.Gravity;import android.view.View;import android.view.ViewGroup;import android.widget.AbsListView;import android.widget.BaseExpandableListAdapter;import android.widget.TextView;/*** 可展开(收缩)列表示例*/public class IdeasExpandableListAdapter extends BaseExpandableListAdapter {private Context mContext = null;// 测试数据，开发时可能来自数据库，网络....private String[] groups = { "家人", "朋友", "同事" };private String[] familis = { "老爸", "老妈", "妹妹" };private String[] friends = { "小李", "张三", "李四" };private String[] colleagues = { "陈总", "李工", "李客户" };private List<String> groupList = null;private List<List<String>> itemList = null;public IdeasExpandableListAdapter(Context context) {this.mContext = context;groupList = new ArrayList<String>();itemList = new ArrayList<List<String>>();initData();}/*** 初始化数据，将相关数据放到List中，方便处理*/private void initData() {for (int i = 0; i < groups.length; i++) {groupList.add(groups[i]);}List<String> item1 = new ArrayList<String>();for (int i = 0; i < familis.length; i++) {item1.add(familis[i]);}List<String> item2 = new ArrayList<String>();for (int i = 0; i < friends.length; i++) {item2.add(friends[i]);}List<String> item3 = new ArrayList<String>();for (int i = 0; i < colleagues.length; i++) {item3.add(colleagues[i]);}itemList.add(item1);itemList.add(item2);itemList.add(item3);}public boolean areAllItemsEnabled() {return false;}/** 设置子节点对象，在事件处理时返回的对象，可存放一些数据*/public Object getChild(int groupPosition, int childPosition) {return itemList.get(groupPosition).get(childPosition);}public long getChildId(int groupPosition, int childPosition) {return childPosition;}/** 字节点视图，这里我们显示一个文本对象*/public View getChildView(int groupPosition, int childPosition,boolean isLastChild, View convertView, ViewGroup parent) {TextView text = null;if (convertView == null) {text = new TextView(mContext);} else {text = (TextView) convertView;}// 获取子节点要显示的名称String name = (String) itemList.get(groupPosition).get(childPosition);// 设置文本视图的相关属性AbsListView.LayoutParams lp = new AbsListView.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, 40);text.setLayoutParams(lp);text.setTextSize(18);text.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);text.setPadding(45, 0, 0, 0);text.setText(name);return text;}/** 返回当前分组的字节点个数*/public int getChildrenCount(int groupPosition) {return itemList.get(groupPosition).size();}/** 返回分组对象，用于一些数据传递，在事件处理时可直接取得和分组相关的数据*/public Object getGroup(int groupPosition) {return groupList.get(groupPosition);}/** 分组的个数*/public int getGroupCount() {return groupList.size();}public long getGroupId(int groupPosition) {return groupPosition;}/** 分组视图，这里也是一个文本视图*/public View getGroupView(int groupPosition, boolean isExpanded,View convertView, ViewGroup parent) {TextView text = null;if (convertView == null) {text = new TextView(mContext);} else {text = (TextView) convertView;}String name = (String) groupList.get(groupPosition);AbsListView.LayoutParams lp = new AbsListView.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, 40);text.setLayoutParams(lp);text.setTextSize(18);text.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);text.setPadding(36, 0, 0, 0);text.setText(name);return text;}/** 判断分组是否为空，本示例中数据是固定的，所以不会为空，我们返回false* 如果数据来自数据库，网络时，可以把判断逻辑写到这个方法中，如果为空* 时返回true*/public boolean isEmpty() {return false;}/** 收缩列表时要处理的东西都放这儿*/public void onGroupCollapsed(int groupPosition) {}/** 展开列表时要处理的东西都放这儿*/public void onGroupExpanded(int groupPosition) {}/** Indicates whether the child and group IDs are stable across changes to* the underlying data.*/public boolean hasStableIds() {return false;}/** Whether the child at the specified position is selectable.*/public boolean isChildSelectable(int groupPosition, int childPosition) {return true;}}