ExpandableListview二级列表的简单实现

效果图如下：

 数据是请求接口得到的，需要导入一些依赖

 compile 'com.squareup.okhttp3:okhttp:3.8.1'
 compile 'com.google.code.gson:gson:2.8.2'

 清单文件中别忘了添加请求网络的权限

 主布局activity_lei_expandable.xml

主Activity:LeiExpandableActivity

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ExpandableListView;
import android.widget.Toast;

import com.littlejie.app.ImageClick.AbstractUiCallBack;
import com.littlejie.app.ImageClick.OkhttpUtils;
import com.littlejie.app.R;

import java.util.HashMap;
import java.util.Map;

public class LeiExpandableActivity extends AppCompatActivity {

    private ExpandableListView expandablelistview;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_lei_expandable);
        initView();
        getGoods();
    }

    private void getGoods() {

        //http://120.27.23.105/product/getCarts?uid=100
        String url = "http://120.27.23.105/product/getCarts";
        Map map = new HashMap<>();
        map.put("uid","100");

        OkhttpUtils.getInstance().asy(map, url, new AbstractUiCallBack() {

            @Override
            public void success(GetCartsBean getCartsBean) {
                expandablelistview.setAdapter(new LeiExpandableAdapter(LeiExpandableActivity.this,getCartsBean.getData()));
            }

            @Override
            public void failure(Exception e) {
                Toast.makeText(LeiExpandableActivity.this, "请求出错", Toast.LENGTH_SHORT).show();
            }
        });
    }

    private void initView(){
        expandablelistview = (ExpandableListView) findViewById(R.id.lei_expandablelistview);
        //去掉自带箭头
      //  expandablelistview.setGroupIndicator(null);
    }
}

适配器：LeiExpandableAdapter

import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;

import com.littlejie.app.R;

import java.util.List;

/**
 * Created by PC-dev on 2018/11/26.
 * expandablelistview继承自 BaseExpandableListAdapter
 */

public class LeiExpandableAdapter extends BaseExpandableListAdapter {

    Context context;
    List data;
    public LeiExpandableAdapter(Context context, List data) {
        this.context = context;
        this.data = data;//整体数据
    }

    /*
        * 一级列表个数
        * */
    @Override
    public int getGroupCount() {
        return data.size();
    }

    /*
    * 每个二级列表的个数
    * */
    @Override
    public int getChildrenCount(int groupPosition) {
        return data.get(groupPosition).getList().size();
    }

    /*
    * 一级列表中的每个item
    * */
    @Override
    public Object getGroup(int groupPosition) {
        return data.get(groupPosition);
    }

    /*
    * 二级列表中的每个item
    * */
    @Override
    public Object getChild(int groupPosition, int childPosition) {
        return data.get(groupPosition).getList().get(childPosition);
    }

    /*
    * 组的id
    * */
    @Override
    public long getGroupId(int groupPosition) {
        return groupPosition;
    }

    /*
    * 子选项的id
    * */
    @Override
    public long getChildId(int groupPosition, int childPosition) {
        return childPosition;
    }

    /*
    * 每个item的id是固定的，一般为true
    * */
    @Override
    public boolean hasStableIds() {
        return true;
    }

    /*
    * isExpanded是否展开
    * */
    @Override
    public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
        if (convertView == null){
            convertView = View.inflate(context,R.layout.expandable_groups,null);
        }
        TextView groups_text = (TextView) convertView.findViewById(R.id.groups_text);
        groups_text.setText(data.get(groupPosition).getSellerName());

        return convertView;
    }

    @Override
    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
        if (convertView == null){
            convertView = View.inflate(context,R.layout.expandable_childs,null);
        }
        TextView childs_text = (TextView) convertView.findViewById(R.id.childs_text);
        childs_text.setText(data.get(groupPosition).getList().get(childPosition).getTitle());
        return convertView;

    }

    /*
    * 二级列表中每个选项能否被选中，如果有点击事件一定有设为true
    * */
    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;
    }
}

请求接口用的2个封装类

OkhttpUtils

import java.io.File;
import java.util.Map;
import java.util.concurrent.TimeUnit;

import okhttp3.FormBody;
import okhttp3.MediaType;
import okhttp3.MultipartBody;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;

public class OkhttpUtils {
  
 private static OkhttpUtils okhttpUtils = null ;  
  
    private OkhttpUtils(){  
  
    }  
  
    public static OkhttpUtils getInstance(){  
  
        if(okhttpUtils == null){  
            okhttpUtils = new OkhttpUtils();  
            client = new OkHttpClient.Builder()
                    .readTimeout(20, TimeUnit.SECONDS)
                    .writeTimeout(20, TimeUnit.SECONDS)
                    .connectTimeout(20, TimeUnit.SECONDS)
                    .build();  
        }  
        return okhttpUtils ;
    }  
  
  
    private static OkHttpClient client ;  
  
  
    public void asy(Map params, String url, AbstractUiCallBack callBack){
        Request request = null ;
  
        if(params != null){  //如果参数不为空，使用post
            FormBody.Builder builder = new FormBody.Builder() ;
            for(Map.Entry entry : params.entrySet()){
                builder.add(entry.getKey(),entry.getValue());  
            }  
            FormBody body =  builder.build();  
            request = new Request.Builder()  //post
                    .url(url)  
                    .post(body)  
                    .build();  
        } else {  //如果参数为空 ，使用get
            request = new Request.Builder()  
                    .url(url)  
                    .build();  
        }  

        client.newCall(request).enqueue(callBack);  
  
    }  
  
    private static final MediaType MEDIA_TYPE_PNG = MediaType.parse("image/png");

    public static void postFile(Map map, String url, File file, AbstractUiCallBack callBack){
  
        String[] array =  file.getAbsolutePath().split("\\/");
  
        MultipartBody.Builder builder = new MultipartBody.Builder();
        builder.setType(MultipartBody.FORM);  
  
        for(Map.Entry entry : map.entrySet()){
            builder.addFormDataPart(entry.getKey(),entry.getValue());  
        }  
        builder.addFormDataPart("imageFileName",array[array.length-1]);  
  
  
        if(file.exists() && file.length() > 0){  
            builder.addFormDataPart("image",array[array.length-1], RequestBody.create(MEDIA_TYPE_PNG,file));
        }  
        MultipartBody body =  builder.build() ;  
  
        Request request = new Request.Builder()  
                .url(url)  
                .post(body)  
                .build();  
        client.newCall(request).enqueue(callBack);
    }
}  

AbstractUiCallBack

import android.os.Handler;
import android.os.Looper;

import com.google.gson.Gson;
import com.google.gson.JsonSyntaxException;

import java.io.IOException;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.Response;

public  abstract  class AbstractUiCallBack implements Callback {
  
    /**  
     * 成功回调  
     * @param t  
     */  
    public abstract void success(T t);  
  
    /**  
     * 失败回调  
     * @param e  
     */  
    public abstract void failure(Exception e);
  
  
    private Handler handler = null ;
    private Class clazz ;
  
    public AbstractUiCallBack(){  
        handler = new Handler(Looper.getMainLooper());

        //  得到的是一个 AbstractUiCallBack 的Type  
       Type type =  getClass().getGenericSuperclass() ;
  
        // 得到的是T的实际Type  
       Type[] arr =  ((ParameterizedType)type).getActualTypeArguments() ;
  
        clazz = (Class) arr[0] ;
  
    }  
  
  
    @Override
    public void onFailure(Call call, IOException e) {
  
        failure(e);
    }  
  
    @Override
    public void onResponse(Call call, Response response) throws IOException {

        try {  
            String result = response.body().string();
            System.out.println("result = " + result);
            Gson gson = new Gson();
  
            final T t = (T) gson.fromJson(result,clazz);  
  
            handler.post(new Runnable() {
                @Override
                public void run() {  
                    success(t);  
                }  
            });  
        } catch (IOException e) {
            e.printStackTrace();  
            failure(e);  
        } catch (JsonSyntaxException e) {
            e.printStackTrace();  
            failure(e);  
        }
    }  
}  

接口返回数据的模型GetCartsBean

import java.util.List;

/**
 * Created by PC-dev on 2018/12/27.
 * 获取购物车bean实体类
 */

public class GetCartsBean {

    /**
     * msg : 请求成功
     * code : 0
     * data : [{"list":[{"bargainPrice":11800,"createtime":"2017-10-10T17:33:37","detailUrl":"https://item.m.jd.com/product/4338107.html?utm#_source=androidapp&utm#_medium=appshare&utm#_campaign=t#_335139774&utm#_term=QQfriends","images":"https://m.360buyimg.com/n0/jfs/t6700/155/2098998076/156185/6cf95035/595dd5a5Nc3a7dab5.jpg!q70.jpg","num":8,"pid":57,"price":5199,"pscid":40,"selected":0,"sellerid":1,"subhead":"【i5 MX150 2G显存】全高清窄边框 8G内存 256固态硬盘 支持指纹识别 预装WIN10系统","title":"小米(MI)Air 13.3英寸全金属轻薄笔记本(i5-7200U 8G 256G PCle SSD MX150 2G独显 FHD 指纹识别 Win10）银\r\n"}],"sellerName":"商家1","sellerid":"1"},{"list":[{"bargainPrice":11800,"createtime":"2017-10-14T21:38:26","detailUrl":"https://item.m.jd.com/product/5025518.html?utm#_source=androidapp&utm#_medium=appshare&utm#_campaign=t#_335139774&utm#_term=QQfriends","images":"https://m.360buyimg.com/n0/jfs/t8830/106/1760940277/195595/5cf9412f/59bf2ef5N5ab7dc16.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t5428/70/1520969931/274676/b644dd0d/591128e7Nd2f70da0.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t5566/365/1519564203/36911/620c750c/591128eaN54ac3363.jpg!q70.jpg","num":1,"pid":58,"price":6399,"pscid":40,"selected":0,"sellerid":2,"subhead":"升级4G大显存！Nvme协议Pcie SSD,速度快人一步】GTX1050Ti就选拯救者！专业游戏键盘&新模具全新设计！","title":"联想(Lenovo)拯救者R720 15.6英寸游戏笔记本电脑(i5-7300HQ 8G 1T+128G SSD GTX1050Ti 4G IPS 黑)"}],"sellerName":"商家2","sellerid":"2"},{"list":[{"bargainPrice":22.9,"createtime":"2017-10-03T23:53:28","detailUrl":"https://item.m.jd.com/product/2542855.html?utm_source=androidapp&utm_medium=appshare&utm_campaign=t_335139774&utm_term=QQfriends","images":"https://m.360buyimg.com/n0/jfs/t1930/284/2865629620/390243/e3ade9c4/56f0a08fNbd3a1235.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t2137/336/2802996626/155915/e5e90d7a/56f0a09cN33e01bd0.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t1882/31/2772215910/389956/c8dbf370/56f0a0a2Na0c86ea6.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t2620/166/2703833710/312660/531aa913/57709035N33857877.jpg!q70.jpg","num":10,"pid":26,"price":88,"pscid":2,"selected":0,"sellerid":3,"subhead":"三只松鼠零食特惠，专区满99减50，满199减100，火速抢购》","title":"三只松鼠 坚果炒货 零食奶油味 碧根果225g/袋"},{"bargainPrice":5599,"createtime":"2017-10-10T17:30:32","detailUrl":"https://item.m.jd.com/product/4824715.html?utm#_source=androidapp&utm#_medium=appshare&utm#_campaign=t#_335139774&utm#_term=QQfriends","images":"https://m.360buyimg.com/n12/jfs/t7768/184/1153704394/148460/f42e1432/599a930fN8a85626b.jpg!q70.jpg","num":1,"pid":59,"price":5599,"pscid":40,"selected":0,"sellerid":3,"subhead":"游戏本选择4G独显，拒绝掉帧】升级版IPS全高清防眩光显示屏，WASD方向键颜色加持，三大出风口立体散热！","title":"戴尔DELL灵越游匣15PR-6648B GTX1050 15.6英寸游戏笔记本电脑(i5-7300HQ 8G 128GSSD+1T 4G独显 IPS)黑"}],"sellerName":"商家3","sellerid":"3"},{"list":[{"bargainPrice":11800,"createtime":"2017-10-14T21:48:08","detailUrl":"https://mitem.jd.hk/ware/view.action?wareId=1988853309&cachekey=1acb07a701ece8d2434a6ae7fa6870a1","images":"https://m.360buyimg.com/n0/jfs/t6130/97/1370670410/180682/1109582a/593276b1Nd81fe723.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t5698/110/2617517836/202970/c9388feb/593276b7Nbd94ef1f.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t5698/110/2617517836/202970/c9388feb/593276b7Nbd94ef1f.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t5815/178/2614671118/51656/7f52d137/593276c7N107b725a.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t5878/60/2557817477/30873/4502b606/593276caN5a7d6357.jpg!q70.jpg","num":7,"pid":60,"price":13888,"pscid":40,"selected":0,"sellerid":4,"subhead":"购买电脑办公部分商品满1元返火车票5元优惠券（返完即止）","title":"全球购 新款Apple MacBook Pro 苹果笔记本电脑 银色VP2新13英寸Bar i5/8G/256G"}],"sellerName":"商家4","sellerid":"4"},{"list":[{"bargainPrice":22.9,"createtime":"2017-10-03T23:53:28","detailUrl":"https://item.m.jd.com/product/2542855.html?utm_source=androidapp&utm_medium=appshare&utm_campaign=t_335139774&utm_term=QQfriends","images":"https://m.360buyimg.com/n0/jfs/t1930/284/2865629620/390243/e3ade9c4/56f0a08fNbd3a1235.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t2137/336/2802996626/155915/e5e90d7a/56f0a09cN33e01bd0.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t1882/31/2772215910/389956/c8dbf370/56f0a0a2Na0c86ea6.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t2620/166/2703833710/312660/531aa913/57709035N33857877.jpg!q70.jpg","num":1,"pid":28,"price":599,"pscid":2,"selected":0,"sellerid":5,"subhead":"三只松鼠零食特惠，专区满99减50，满199减100，火速抢购》","title":"三只松鼠 坚果炒货 零食奶油味 碧根果225g/袋"}],"sellerName":"商家5","sellerid":"5"},{"list":[{"bargainPrice":22.9,"createtime":"2017-10-14T21:48:08","detailUrl":"https://item.m.jd.com/product/2542855.html?utm_source=androidapp&utm_medium=appshare&utm_campaign=t_335139774&utm_term=QQfriends","images":"https://m.360buyimg.com/n0/jfs/t1930/284/2865629620/390243/e3ade9c4/56f0a08fNbd3a1235.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t2137/336/2802996626/155915/e5e90d7a/56f0a09cN33e01bd0.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t1882/31/2772215910/389956/c8dbf370/56f0a0a2Na0c86ea6.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t2620/166/2703833710/312660/531aa913/57709035N33857877.jpg!q70.jpg","num":1,"pid":29,"price":588,"pscid":2,"selected":0,"sellerid":6,"subhead":"三只松鼠零食特惠，专区满99减50，满199减100，火速抢购》","title":"三只松鼠 坚果炒货 零食奶油味 碧根果225g/袋"},{"bargainPrice":11800,"createtime":"2017-10-03T23:53:28","detailUrl":"https://mitem.jd.hk/ware/view.action?wareId=1988853309&cachekey=1acb07a701ece8d2434a6ae7fa6870a1","images":"https://m.360buyimg.com/n0/jfs/t6130/97/1370670410/180682/1109582a/593276b1Nd81fe723.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t5698/110/2617517836/202970/c9388feb/593276b7Nbd94ef1f.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t5698/110/2617517836/202970/c9388feb/593276b7Nbd94ef1f.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t5815/178/2614671118/51656/7f52d137/593276c7N107b725a.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t5878/60/2557817477/30873/4502b606/593276caN5a7d6357.jpg!q70.jpg","num":1,"pid":62,"price":15999,"pscid":40,"selected":0,"sellerid":6,"subhead":"购买电脑办公部分商品满1元返火车票5元优惠券（返完即止）","title":"全球购 新款Apple MacBook Pro 苹果笔记本电脑 银色VP2新13英寸Bar i5/8G/256G"}],"sellerName":"商家6","sellerid":"6"},{"list":[{"bargainPrice":111.99,"createtime":"2017-10-14T21:39:05","detailUrl":"https://item.m.jd.com/product/4719303.html?utm_source=androidapp&utm_medium=appshare&utm_campaign=t_335139774&utm_term=QQfriends","images":"https://m.360buyimg.com/n0/jfs/t9004/210/1160833155/647627/ad6be059/59b4f4e1N9a2b1532.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t7504/338/63721388/491286/f5957f53/598e95f1N7f2adb87.jpg!q70.jpg|https://m.360buyimg.com/n0/jfs/t7441/10/64242474/419246/adb30a7d/598e95fbNd989ba0a.jpg!q70.jpg","num":1,"pid":1,"price":118,"pscid":1,"selected":0,"sellerid":17,"subhead":"每个中秋都不能简单，无论身在何处，你总需要一块饼让生活更圆满，京东月饼让爱更圆满京东自营，闪电配送，更多惊喜，快用手指戳一下","title":"北京稻香村 稻香村中秋节月饼 老北京月饼礼盒655g"}],"sellerName":"商家17","sellerid":"17"}]
     */

    private String msg;
    private String code;
    /**
     * list : [{"bargainPrice":11800,"createtime":"2017-10-10T17:33:37","detailUrl":"https://item.m.jd.com/product/4338107.html?utm#_source=androidapp&utm#_medium=appshare&utm#_campaign=t#_335139774&utm#_term=QQfriends","images":"https://m.360buyimg.com/n0/jfs/t6700/155/2098998076/156185/6cf95035/595dd5a5Nc3a7dab5.jpg!q70.jpg","num":8,"pid":57,"price":5199,"pscid":40,"selected":0,"sellerid":1,"subhead":"【i5 MX150 2G显存】全高清窄边框 8G内存 256固态硬盘 支持指纹识别 预装WIN10系统","title":"小米(MI)Air 13.3英寸全金属轻薄笔记本(i5-7200U 8G 256G PCle SSD MX150 2G独显 FHD 指纹识别 Win10）银\r\n"}]
     * sellerName : 商家1
     * sellerid : 1
     */

    private List data;

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    public List getData() {
        return data;
    }

    public void setData(List data) {
        this.data = data;
    }

    public static class DataBean {
        private String sellerName;
        private String sellerid;
        /**
         * bargainPrice : 11800.0
         * createtime : 2017-10-10T17:33:37
         * detailUrl : https://item.m.jd.com/product/4338107.html?utm#_source=androidapp&utm#_medium=appshare&utm#_campaign=t#_335139774&utm#_term=QQfriends
         * images : https://m.360buyimg.com/n0/jfs/t6700/155/2098998076/156185/6cf95035/595dd5a5Nc3a7dab5.jpg!q70.jpg
         * num : 8
         * pid : 57
         * price : 5199.0
         * pscid : 40
         * selected : 0
         * sellerid : 1
         * subhead : 【i5 MX150 2G显存】全高清窄边框 8G内存 256固态硬盘 支持指纹识别 预装WIN10系统
         * title : 小米(MI)Air 13.3英寸全金属轻薄笔记本(i5-7200U 8G 256G PCle SSD MX150 2G独显 FHD 指纹识别 Win10）银

         */

        private List list;

        public String getSellerName() {
            return sellerName;
        }

        public void setSellerName(String sellerName) {
            this.sellerName = sellerName;
        }

        public String getSellerid() {
            return sellerid;
        }

        public void setSellerid(String sellerid) {
            this.sellerid = sellerid;
        }

        public List getList() {
            return list;
        }

        public void setList(List list) {
            this.list = list;
        }

        public static class ListBean {
            private double bargainPrice;
            private String createtime;
            private String detailUrl;
            private String images;
            private int num;
            private int pid;
            private double price;
            private int pscid;
            private int selected;
            private int sellerid;
            private String subhead;
            private String title;

            public double getBargainPrice() {
                return bargainPrice;
            }

            public void setBargainPrice(double bargainPrice) {
                this.bargainPrice = bargainPrice;
            }

            public String getCreatetime() {
                return createtime;
            }

            public void setCreatetime(String createtime) {
                this.createtime = createtime;
            }

            public String getDetailUrl() {
                return detailUrl;
            }

            public void setDetailUrl(String detailUrl) {
                this.detailUrl = detailUrl;
            }

            public String getImages() {
                return images;
            }

            public void setImages(String images) {
                this.images = images;
            }

            public int getNum() {
                return num;
            }

            public void setNum(int num) {
                this.num = num;
            }

            public int getPid() {
                return pid;
            }

            public void setPid(int pid) {
                this.pid = pid;
            }

            public double getPrice() {
                return price;
            }

            public void setPrice(double price) {
                this.price = price;
            }

            public int getPscid() {
                return pscid;
            }

            public void setPscid(int pscid) {
                this.pscid = pscid;
            }

            public int getSelected() {
                return selected;
            }

            public void setSelected(int selected) {
                this.selected = selected;
            }

            public int getSellerid() {
                return sellerid;
            }

            public void setSellerid(int sellerid) {
                this.sellerid = sellerid;
            }

            public String getSubhead() {
                return subhead;
            }

            public void setSubhead(String subhead) {
                this.subhead = subhead;
            }

            public String getTitle() {
                return title;
            }

            public void setTitle(String title) {
                this.title = title;
            }
        }
    }
}

适配器中引入了2个布局，分别是一级列表和二级列表的布局文件

一级列表布局文件 expandable_groups.xml

二级列表布局文件expandable_childs.xml