购物车呢

MainActivity

package com.example.wocao;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.DragAndDropPermissions;
import android.view.View;
import android.widget.CheckBox;
import android.widget.ExpandableListView;
import android.widget.TextView;

import com.example.wocao.util.RetrofitUtil;

import java.util.List;

import de.greenrobot.event.EventBus;
import de.greenrobot.event.Subscribe;
import io.reactivex.Observable;
import io.reactivex.Observer;
import io.reactivex.android.schedulers.AndroidSchedulers;
import io.reactivex.disposables.Disposable;
import io.reactivex.schedulers.Schedulers;

public class MainActivity extends AppCompatActivity {
    private MyAdapter adapter;
    private ExpandableListView expandableListView;
    private CheckBox btnCheckAll;
    private TextView tvAllPrice;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        EventBus.getDefault().register(this);
        btnCheckAll = findViewById(R.id.btnCheckAll);
        expandableListView = findViewById(R.id.expandList);
        tvAllPrice = findViewById(R.id.tvAllPrice);
        initData();
    }

    private void initData() {

        Observable guc = RetrofitUtil.getInstance().getZhujieApi().getGUC();
        guc.observeOn(AndroidSchedulers.mainThread())
                .subscribeOn(Schedulers.io())
                .subscribe(new Observer() {



                    @Override
                    public void onSubscribe(Disposable d) {

                    }

                    @Override
                    public void onNext(GucBean value) {
                        List data = value.getData();
                        Log.d("TAG", data.get(0).getSellerName());
                        adapter = new MyAdapter(data,MainActivity.this);
                               expandableListView.setAdapter(adapter);
                        for (int i = 0; i < data.size(); i++) {
                            expandableListView.expandGroup(i);
                        }
                    }

                    @Override
                    public void onError(Throwable e) {

                    }

                    @Override
                    public void onComplete() {

                    }
                });
        btnCheckAll.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                adapter.changeAllListCbState(btnCheckAll.isChecked());
            }
        });
    }
    @Subscribe
    public void onMessageEvent(MessageEvent event) {
        btnCheckAll.setChecked(event.isChecked());
    }
    @Subscribe
    public void onMessageEvent(PriceAndCountEvent event) {
        Log.d("ssss", event.getPrice()+"");
        Log.d("ssss", event.getCount()+"");
        tvAllPrice.setText("结算：$"+event.getPrice()+"");
      //  tvAllPrice.setText("￥" + event.getPrice());
    }
}

MyAdapter

package com.example.wocao;

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

import com.facebook.drawee.view.SimpleDraweeView;

import java.util.List;

import de.greenrobot.event.EventBus;

public class MyAdapter extends BaseExpandableListAdapter {
    private List data;
    private Context context;

    public MyAdapter(List data, Context context) {
        this.data = data;
        this.context = context;
    }

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

    @Override
    public int getChildrenCount(int groupPosition) {
        return data.get(groupPosition).getList().size();
    }

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

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

    @Override
    public View getGroupView(final int groupPosition, boolean isExpanded, View view, ViewGroup parent) {
        if(view==null) {
            view= LayoutInflater.from(context).inflate(R.layout.layout_group,null);
        }

            final CheckBox group_choosed = view.findViewById(R.id.group_choosed);
            TextView group_tv = view.findViewById(R.id.group_tv);

            group_tv.setText(data.get(groupPosition).getSellerName());
            if(data.get(groupPosition).isChecked()){
                group_choosed.setChecked(true);
            }else {
                group_choosed.setChecked(false);
            }
            group_choosed.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    data.get(groupPosition).setChecked(group_choosed.isChecked());
                    changeChild(groupPosition,group_choosed.isChecked());
                    changeAllCbState(isAllGroupCbSelected());
                    EventBus.getDefault().post(compute());
                    notifyDataSetChanged();
                }
            });

        return view;
    }

    @Override
    public View getChildView(final int groupPosition, final int childPosition, boolean isLastChild, View view, ViewGroup parent) {
        final List list = data.get(groupPosition).getList();
        if (view==null) {
            view = LayoutInflater.from(context).inflate(R.layout.layout_child, null);
        }
            final CheckBox child_choosed = view.findViewById(R.id.child_choosed);
            SimpleDraweeView img = view.findViewById(R.id.img);
            TextView  titleName= view.findViewById(R.id.titleName);
            TextView  btnSub = view.findViewById(R.id.btnSub);
            TextView  btnAdd= view.findViewById(R.id.btnAdd);
            final TextView  showNum = view.findViewById(R.id.showNum);
        /* showNum  btnSub   btnAdd*/
            titleName.setText(list.get(childPosition).getTitle());

            String images = list.get(childPosition).getImages();
            String[] split = images.split("\\|");
            img.setImageURI(split[0]);
            btnSub.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                   /* int num = list.get(childPosition).getNum();
                    num++;
                    list.get(childPosition).setNum(num);

                    notifyDataSetChanged();*/
                }
            });
            btnAdd.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
             /*   int num = list.get(childPosition).getNum();
                num++;
                list.get(childPosition).setNum(num);
                showNum.setText(list.get(childPosition).getNum());
                notifyDataSetChanged();
*/

            }
        });
            if(list.get(childPosition).isChecked()){
                child_choosed.setChecked(true);
            }else {
                child_choosed.setChecked(false);
            }

            child_choosed.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View v) {
                    //设置该条目对象里的setChildchecked属性值
                    list.get(childPosition).setChecked(child_choosed.isChecked());
                    //二级checkbox全部选中
                    if (isAllChildCbSelected(groupPosition)) {
                        //一级框就选中
                        changeGroup(groupPosition, true);
                        changeAllCbState(isAllGroupCbSelected());

                    } else {
                        //否则不选中
                        changeGroup(groupPosition, false);
                    }
                    EventBus.getDefault().post(compute());
                    notifyDataSetChanged();
                }
            });



        return view;
    }

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

    //改变一级列表状态
    private void changeGroup(int groupPosition,boolean flag){

        GucBean.DataBean dataBean = data.get(groupPosition);
        dataBean.setChecked(flag);

    }
    //改变二级列表状态
    private void changeChild(int groupPosition,boolean flag){

        List list = data.get(groupPosition).getList();

        for (int i = 0; i < list.size(); i++) {
            GucBean.DataBean.ListBean listBean = list.get(i);
            listBean.setChecked(flag);
        }

    }

    //判断一级列表是否全部选中
    private boolean isAllGroupCbSelected() {
        for (int i = 0; i < data.size(); i++) {
            GucBean.DataBean dataBean = data.get(i);

            if(!dataBean.isChecked()){
                return  false;
            }

        }
        return true;
    }
    //判断二级列表是否全部选中
    private boolean isAllChildCbSelected(int groupPosition){

        for (int i = 0; i < data.get(groupPosition).getList().size(); i++) {

            GucBean.DataBean.ListBean listBean = data.get(groupPosition).getList().get(i);
            if(!listBean.isChecked()){
                return false;
            }
        }
        return true;
    }

    private void changeAllCbState(boolean flag) {
        MessageEvent messageEvent = new MessageEvent();
        messageEvent.setChecked(flag);
        EventBus.getDefault().post(messageEvent);
    }


    private PriceAndCountEvent compute() {
        int count = 0;
        int price = 0;
        for (int i = 0; i < data.get(i).getList().size(); i++) {
//            List datasBeen = childList.get(i);
            List list = this.data.get(i).getList();
            for (int j = 0; j < list.size(); j++) {
                GucBean.DataBean.ListBean listBean = list.get(j);

                if (listBean.isChecked()) {
                    price += listBean.getNum() * listBean.getPrice();
                    count += listBean.getNum();
                }
            }
        }
        PriceAndCountEvent priceAndCountEvent = new PriceAndCountEvent();
        priceAndCountEvent.setCount(count);
        priceAndCountEvent.setPrice(price);
        return priceAndCountEvent;
    }
    //设置反选全选
    public void changeAllListCbState(boolean flag) {
        for (int i = 0; i < data.size(); i++) {
            changeGroup(i, flag);
            changeChild(i, flag);
        }
        EventBus.getDefault().post(compute());
        notifyDataSetChanged();
    }

}

PriceAndCountEvent

package com.example.wocao;

/**
 * author: Wangxinrun
 * Date: 2018/6/28
 * Time: 19:20
 */

public class PriceAndCountEvent {
    private int price;
    private int count;

    public int getPrice() {
        return price;
    }

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

    public int getCount() {
        return count;
    }

    public void setCount(int count) {
        this.count = count;
    }
}

MessageEvent

package com.example.wocao;

/**
 * author: Wangxinrun
 * Date: 2018/6/28
 * Time: 19:20
 */

public class MessageEvent {
    private boolean checked;

    public boolean isChecked() {
        return checked;
    }

    public void setChecked(boolean checked) {
        this.checked = checked;
    }
}