<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical" android:layout_width="match_parent"
  android:layout_height="match_parent">
  <ExpandableListView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/el">
  </ExpandableListView>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  android:orientation="horizontal" android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:gravity="center_vertical">
  <ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    app:srcCompat="@mipmap/ic_launcher"
    android:id="@+id/iv_group" />
  <TextView
    android:text="TextView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/tv_group" />
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  android:orientation="horizontal" android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:gravity="center_vertical"
  android:paddingLeft="50dp">
  <ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    app:srcCompat="@mipmap/ic_launcher"
    android:id="@+id/iv_item" />
  <TextView
    android:text="TextView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/tv_item" />
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical" android:layout_width="match_parent"
  android:layout_height="match_parent">
  <EditText
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/et"
    android:hint="请输入想对他说的话"/>
</LinearLayout>

import android.content.DialogInterface;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
/**
 * Created by panchengjia on 2016/12/2.
 */
public class ExpandableListViewDemo extends AppCompatActivity {
  ExpandableListView el;
  //定义分组名以及对应的图片数组，需一一对应
  String[] country={"魏国","蜀国","吴国"};
  int[] icon={R.mipmap.wei,R.mipmap.shu,R.mipmap.wu};
  //使用二维定义组内成员以及对应头像，同样需要以一一对应
  String[][] heros={{"司马懿","郭嘉","夏侯惇","甄姬"},{"刘备","赵云","张飞"},{"孙权","周瑜"}};
  int[][] icons={{R.mipmap.simayi,R.mipmap.guojia,R.mipmap.xiahoudun,R.mipmap.zhenji},
      {R.mipmap.liubei,R.mipmap.zhaoyun,R.mipmap.zhangfei},{R.mipmap.sunquan,R.mipmap.zhouyu}};
  @Override
  protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.expandable_layout);
    el= (ExpandableListView) findViewById(R.id.el);
    //设置点击下拉子菜单的监听事件
    el.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
      @Override
      public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
        //获取分组成员的姓名
        TextView tv = (TextView) v.findViewById(R.id.tv_item);
        String name = tv.getText().toString();
        //调用show方法（自定义AlertDialog）
        show(v,name);
        return false;
      }
    });
    el.setAdapter(new MyAdapter());//设置自定义适配器
  }
  //定义show方法调出AlertDialog（不再赘述，详情请看前期相关博文，文章末尾有链接）
  public void show(View v,String name){
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setTitle(name);//设置标题名为传入的字符串（分组内点击对应的人物名）
    View msg = getLayoutInflater().inflate(R.layout.altertdialog_layout,null);
    builder.setView(msg);
    builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
      @Override
      public void onClick(DialogInterface dialog, int which) {
        Toast.makeText(ExpandableListViewDemo.this, "已发送", Toast.LENGTH_SHORT).show();
      }
    });
    builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
      @Override
      public void onClick(DialogInterface dialog, int which) {
        Toast.makeText(ExpandableListViewDemo.this, "不想说了", Toast.LENGTH_SHORT).show();
      }
    });
    builder.show();
  }
  //设置自定义适配器
  class MyAdapter extends BaseExpandableListAdapter{
    //获取国家个数
    @Override
    public int getGroupCount() {
      return country.length;
    }
    //获取每个国家对应的人数
    @Override
    public int getChildrenCount(int groupPosition) {
      return heros[groupPosition].length;
    }
    //获取对应国家名
    @Override
    public Object getGroup(int groupPosition) {
      return country[groupPosition];
    }
    //获取对应国家对应的任务
    @Override
    public Object getChild(int groupPosition, int childPosition) {
      return heros[groupPosition][childPosition];
    }
    //获取选择的国家对应数组下标
    @Override
    public long getGroupId(int groupPosition) {
      return groupPosition;
    }
    //获取选择的任务对应数组下标
    @Override
    public long getChildId(int groupPosition, int childPosition) {
      return childPosition;
    }
    //表示人物和国家ID是否稳定的更改底层数据
    @Override
    public boolean hasStableIds() {
      return true;
    }
    //获取一个视图显示国家名以及对应的图标（ListView适配器优化）
    @Override
    public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
      ViewHolder vh;
      if(convertView==null){
        convertView=getLayoutInflater().inflate(R.layout.group_layout,null);
        vh=new ViewHolder();
        vh.tv= (TextView) convertView.findViewById(R.id.tv_group);
        vh.iv= (ImageView) convertView.findViewById(R.id.iv_group);
        convertView.setTag(vh);
      }
      vh= (ViewHolder) convertView.getTag();
      vh.tv.setText(country[groupPosition]);
      vh.iv.setImageResource(icon[groupPosition]);
      return convertView;
    }
    //获取一个视图显示国家对应人物以及对应的图标（ListView适配器优化）
    @Override
    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
      ViewHolder vh;
      if(convertView==null){
        convertView=getLayoutInflater().inflate(R.layout.child_layout,null);
        vh=new ViewHolder();
        vh.tv= (TextView) convertView.findViewById(R.id.tv_item);
        vh.iv= (ImageView) convertView.findViewById(R.id.iv_item);
        convertView.setTag(vh);
      }
      vh= (ViewHolder) convertView.getTag();
      vh.tv.setText(heros[groupPosition][childPosition]);
      vh.iv.setImageResource(icons[groupPosition][childPosition]);
      return convertView;
    }
    class ViewHolder{
      ImageView iv;
      TextView tv;
    }
    //设置子选项（对应人物）是可选的
    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
      return true;
    }
  }
}