购物车简单实现（二级列表ExpandableListView）

MVP请求数据自行解决

MainActivity

package com.zjh.administrat.shopping_cartdemo.view;

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

import com.zjh.administrat.shopping_cartdemo.R;
import com.zjh.administrat.shopping_cartdemo.adapter.MyAdapter;
import com.zjh.administrat.shopping_cartdemo.bean.ShoppingBean;
import com.zjh.administrat.shopping_cartdemo.presenter.IPresenterImpl;

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

public class MainActivity extends AppCompatActivity implements IView {

    private String urlStr = "http://www.zhaoapi.cn/product/getCarts";
    private IPresenterImpl iPresenter;
    private ExpandableListView el_cart;
    private CheckBox cb_cart_all_select;
    private TextView tv_cart_total_price;
    private Button btn_cart_pay;
    private MyAdapter adapter;
    private ShoppingBean data;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        initData();
        adapter = new MyAdapter(this);
        el_cart.setAdapter(adapter);
    }

    //初始化view
    private void initData() {
        iPresenter = new IPresenterImpl(this);
        Map map = new HashMap<>();
        map.put("uid", "71");
        iPresenter.pRequestData(urlStr, map, ShoppingBean.class);
    }

    //B.刷新checkbox状态和总价和总数量
    private void refreshSelectedAndTotalPriceAndTotalNumber() {
        //去判断是否所有得商品都被选中
        boolean allProductsSelected = adapter.isAllProductsSelected();
        //设置给全选
        cb_cart_all_select.setChecked(allProductsSelected);
        //计算总价
        float totalPrice = adapter.calculateTotalPrice();
        tv_cart_total_price.setText("总价:￥"+totalPrice);
        //计算总数量
        int totalNumber = adapter.calculateTotalNumber();
        btn_cart_pay.setText("去结算("+totalNumber+")");
    }

    //初始化的操作
    private void initView() {
        el_cart = findViewById(R.id.el_cart);
        cb_cart_all_select = findViewById(R.id.cb_cart_all_select);
        tv_cart_total_price = findViewById(R.id.tv_cart_total_price);
        btn_cart_pay = findViewById(R.id.btn_cart_pay);

        //全选按钮
        findViewById(R.id.cb_cart_all_select).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //底部全选按钮选中的时候所有得商品都被选中
                boolean allProductsSelected = adapter.isAllProductsSelected();
                adapter.changeAllProductStatus(!allProductsSelected);
                adapter.notifyDataSetChanged();
                //刷新底部数据
                refreshSelectedAndTotalPriceAndTotalNumber();
            }
        });
    }

    //获取数据
    @Override
    public void viewData(Object object) {
        data = (ShoppingBean) object;
        adapter.setDatas(data.getData());

        for (int p = 0; p < data.getData().size(); p++) {
            el_cart.expandGroup(p);
        }

        //回调方法
        adapter.setOnCartListChangeListener(new MyAdapter.OnCartListChangeListener() {
            @Override
            public void onSellerCheckedChange(int i) {
                //商家被点击
                boolean currentSellerAllProductSelected = adapter.isCurrentSellerAllProductSelected(i);
                adapter.changeCurrentSellerAllProductsStatus(i, !currentSellerAllProductSelected);
                adapter.notifyDataSetChanged();
                //B.刷新底部数据
                refreshSelectedAndTotalPriceAndTotalNumber();
            }

            @Override
            public void onProductCheckedChange(int i, int i1) {
                //点击商品得复选框
                adapter.changeCurrentProductStatus(i, i1);
                adapter.notifyDataSetChanged();
                //B.刷新底部数据
                refreshSelectedAndTotalPriceAndTotalNumber();
            }

            @Override
            public void onProducNumberChange(int i, int i1, int number) {
                //当加减被点击
                adapter.changeCurrentProductNumber(i, i1, number);
                adapter.notifyDataSetChanged();
                //B.刷新底部数据
                refreshSelectedAndTotalPriceAndTotalNumber();
            }
        });

    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        iPresenter.onDetch();
    }

}

AddSubView自定（商品数量）

package com.zjh.administrat.shopping_cartdemo.view;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;

import com.zjh.administrat.shopping_cartdemo.R;

public class AddSubView extends LinearLayout implements View.OnClickListener {

    private int number = 1;
    private TextView sub_tv, product_number_tv, add_tv;

    public AddSubView(Context context) {
        this(context,null);
    }

    public AddSubView(Context context, AttributeSet attrs) {
        this(context, attrs,0);
    }

    public AddSubView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

        View view = inflate(context, R.layout.add_remove, this);
        sub_tv = view.findViewById(R.id.sub_tv);
        product_number_tv = view.findViewById(R.id.product_number_tv);
        add_tv = view.findViewById(R.id.add_tv);

        sub_tv.setOnClickListener(this);
        add_tv.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.sub_tv:
                if (number > 1) {
                    --number;
                    product_number_tv.setText(number+"");
                    if (mNumberChangeListener != null) {
                        mNumberChangeListener.onNumberChange(number);
                    }
                } else {
                    Toast.makeText(getContext(), "我是有底线的", Toast.LENGTH_SHORT).show();
                }
                break;
            case R.id.add_tv:
                if (number < 9) {
                    ++number;
                    product_number_tv.setText(number+"");
                    if (mNumberChangeListener != null) {
                        mNumberChangeListener.onNumberChange(number);
                    }
                } else {
                    Toast.makeText(getContext(), "每人限购10件", Toast.LENGTH_SHORT).show();
                }
                break;
            default:
                break;
        }
    }

    public int getNumber() {
        return number;
    }

    public void setNumber(int number) {
        this.number = number;
        product_number_tv.setText(number+"");
    }

    //成员变量
    OnNumberChangeListener mNumberChangeListener;

    public void setOnNumberChangeListener(OnNumberChangeListener onNumberChangeListener) {
        this.mNumberChangeListener = onNumberChangeListener;
    }

    public interface OnNumberChangeListener {
        void onNumberChange(int number);
    }

}

MyAdapter适配器

package com.zjh.administrat.shopping_cartdemo.adapter;

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.ImageView;
import android.widget.TextView;

import com.bumptech.glide.Glide;
import com.zjh.administrat.shopping_cartdemo.R;
import com.zjh.administrat.shopping_cartdemo.bean.ShoppingBean;
import com.zjh.administrat.shopping_cartdemo.view.AddSubView;

import java.util.ArrayList;
import java.util.List;

public class MyAdapter extends BaseExpandableListAdapter {
    private List list;
    private Context mContext;

    public MyAdapter(Context context) {
        mContext = context;
        list = new ArrayList<>();
    }

    public void setDatas(List data) {
        if (data != null){
            list.addAll(data);
        }
        notifyDataSetChanged();
    }

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

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


    @Override
    public View getGroupView(final int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
        ShoppingBean.DataBean dataBean = list.get(groupPosition);
        ParentViewHolder parentViewHolder;
        if (convertView == null) {
            convertView = LayoutInflater.from(mContext).inflate(R.layout.item_cart_parent, parent, false);
            parentViewHolder = new ParentViewHolder(convertView);
            convertView.setTag(parentViewHolder);
        } else {
            parentViewHolder = (ParentViewHolder) convertView.getTag();
        }
        parentViewHolder.seller_name_tv.setText(dataBean.getSellerName());
        boolean currentSellerAllProductSelected = isCurrentSellerAllProductSelected(groupPosition);
        parentViewHolder.seller_cb.setChecked(currentSellerAllProductSelected);
        //D.设置点击CheckBox
        parentViewHolder.seller_cb.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mOnCartListChangeListener != null) {
                    mOnCartListChangeListener.onSellerCheckedChange(groupPosition);
                }
            }
        });
        return convertView;
    }

    @Override
    public View getChildView(final int groupPosition, final int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
        ChildViewHolder childViewHolder;
        if (convertView == null) {
            convertView = LayoutInflater.from(mContext).inflate(R.layout.item_cart_child, parent, false);
            childViewHolder = new ChildViewHolder(convertView);
            convertView.setTag(childViewHolder);
        } else {
            childViewHolder = (ChildViewHolder) convertView.getTag();
        }
        //设置商品名字
        childViewHolder.product_title_name_tv.setText(list.get(groupPosition).getList().get(childPosition).getTitle());
        //设置商品单价
        childViewHolder.product_price_tv.setText("￥:"+list.get(groupPosition).getList().get(childPosition).getPrice()+"");
        //设置复选框是否选中
        childViewHolder.child_cb.setChecked(list.get(groupPosition).getList().get(childPosition).getSelected() == 1);
        //设置组合式自定义控件内部的数量
        childViewHolder.add_remove_view.setNumber(list.get(groupPosition).getList().get(childPosition).getNum());

        String str = "";
        int length = list.get(groupPosition).getList().get(childPosition).getImages().length();
        for (int j = 0; j < length; j++) {
            if (list.get(groupPosition).getList().get(childPosition).getImages().substring(j, j + 1).equals("|")) {
                str = list.get(groupPosition).getList().get(childPosition).getImages().substring(j + 1, length).trim();
            }
        }
        Glide.with(mContext).load(str).into(childViewHolder.product_icon_iv);

        //D.设置商品CheckBox的点击事件,通过接口回调,暴露给外面
       childViewHolder.child_cb.setOnClickListener(new View.OnClickListener() {
           @Override
           public void onClick(View v) {
               if (mOnCartListChangeListener != null) {
                   mOnCartListChangeListener.onProductCheckedChange(groupPosition, childPosition);
               }
           }
       });

        //D.设置商品数量的点击事件,通过接口回调,暴露给外面
        childViewHolder.add_remove_view.setOnNumberChangeListener(new AddSubView.OnNumberChangeListener() {
            @Override
            public void onNumberChange(int number) {
                if (mOnCartListChangeListener != null){
                    mOnCartListChangeListener.onProducNumberChange(groupPosition, childPosition, number);
                }
            }
        });

        return convertView;
    }

        public boolean isCurrentSellerAllProductSelected (int i){
            //根据商品改变商家--如果商品全部选中商家则选中--有一个商品没选中则商家不选中
            ShoppingBean.DataBean dataBean = list.get(i);
            List beans = dataBean.getList();
            for (ShoppingBean.DataBean.ListBean bean : beans) {
                if (bean.getSelected() == 0) {
                    return false;
                }
            }
            return true;
        }

        public boolean isAllProductsSelected () {
            //根据商品改变全选--如果商品全部选中全选则选中--有一个商品没选中则全选不选中
            for (int x = 0; x < list.size(); x++) {
                ShoppingBean.DataBean dataBean = list.get(x);
                List list1 = dataBean.getList();
                for (int j = 0; j < list1.size(); j++) {
                    if (list1.get(j).getSelected() == 0) {
                        return false;
                    }
                }
            }
            return true;
        }

        public int calculateTotalNumber () {
            //计算总数量
            int totalNumber = 0;
            for (int i = 0; i < list.size(); i++) {
                ShoppingBean.DataBean dataBean = list.get(i);
                List list1 = dataBean.getList();
                for (int j = 0; j < list1.size(); j++) {
                    if (list1.get(j).getSelected() == 1) {
                        int num = list1.get(j).getNum();
                        totalNumber += num;
                    }
                }
            }
            return totalNumber;
        }

        public float calculateTotalPrice () {
            //获取总价
            float totalPrice = 0;
            for (int i = 0; i < list.size(); i++) {
                ShoppingBean.DataBean dataBean = list.get(i);
                List list1 = dataBean.getList();
                for (int j = 0; j < list1.size(); j++) {
                    if (list1.get(j).getSelected() == 1) {
                        float price = (float) list1.get(j).getPrice();
                        int num = list1.get(j).getNum();
                        totalPrice += price * num;
                    }
                }
            }
            return totalPrice;
        }

        //C.当商品组的全选框点击时,更新所有商品的状态
        public void changeCurrentSellerAllProductsStatus ( int i, boolean isSelected){
            ShoppingBean.DataBean dataBean = list.get(i);
            List beans = dataBean.getList();
            for (int j = 0; j < beans.size(); j++) {
                ShoppingBean.DataBean.ListBean bean = beans.get(j);
                bean.setSelected(isSelected ? 1 : 0);
            }
        }

        //C.当商家子条目的全选框选中时,更新其状态
        public void changeCurrentProductStatus ( int i, int i1){
            ShoppingBean.DataBean dataBean = list.get(i);
            List list1 = dataBean.getList();
            ShoppingBean.DataBean.ListBean listBean = list1.get(i1);
            listBean.setSelected(listBean.getSelected() == 0 ? 1 : 0);
        }

        //C.设置所有商品的状态
        public void changeAllProductStatus (boolean selected){
            for (int x = 0; x < list.size(); x++) {
                ShoppingBean.DataBean dataBean = list.get(x);
                List list1 = dataBean.getList();
                for (int j = 0; j < list1.size(); j++) {
                    list1.get(j).setSelected(selected ? 1 : 0);
                }
            }
        }

        //C.当加减器被点击时,调用,改变里面当前商品的数量 参数1定位那个商家 参数2定位哪个商品 参数3定位改变具体的数量是多少
        public void changeCurrentProductNumber (int i, int i1, int number){
            ShoppingBean.DataBean dataBean = list.get(i);
            List list = dataBean.getList();
            ShoppingBean.DataBean.ListBean listBean = list.get(i1);
            listBean.setNum(number);

        }

    //成员变量
    OnCartListChangeListener mOnCartListChangeListener;
    //D.方法的set
    public void setOnCartListChangeListener (OnCartListChangeListener onCartListChangeListener){
        mOnCartListChangeListener = onCartListChangeListener;
    }
    public interface OnCartListChangeListener {
            //当商家的checkBox点击时回调
            void onSellerCheckedChange(int i);

             //当点击子条目商品的CheckBox回调
            void onProductCheckedChange(int i, int i1);

            //当点击加减按钮的回调
            void onProducNumberChange(int i, int i1, int number);
        }


        public static class ParentViewHolder {
            public CheckBox seller_cb;
            public TextView seller_name_tv;

            public ParentViewHolder(View rootView) {
                seller_cb = rootView.findViewById(R.id.seller_cb);
                seller_name_tv = rootView.findViewById(R.id.seller_name_tv);
            }
        }

        public static class ChildViewHolder {
            public CheckBox child_cb;
            public ImageView product_icon_iv;
            public TextView product_title_name_tv;
            public TextView product_price_tv;
            public AddSubView add_remove_view;

            public ChildViewHolder(View rootView) {
                child_cb = rootView.findViewById(R.id.child_cb);
                product_icon_iv = rootView.findViewById(R.id.product_icon_iv);
                product_title_name_tv = rootView.findViewById(R.id.product_title_name_tv);
                product_price_tv = rootView.findViewById(R.id.product_price_tv);
                add_remove_view = rootView.findViewById(R.id.add_remove_view);
            }
        }

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

        @Override
        public Object getGroup ( int groupPosition){
            return null;
        }

        @Override
        public Object getChild ( int groupPosition, int childPosition){
            return null;
        }

        @Override
        public long getGroupId ( int groupPosition){
            return 0;
        }

        @Override
        public long getChildId ( int groupPosition, int childPosition){
            return 0;
        }

        @Override
        public boolean hasStableIds () {
            return false;
        }

}

以下是布局

activity_main.xml

item_cart_parent.xml商家

item_cart_child.xml商品

add_remove.xml加减数量