购物车的完成

//MainActivity

public class MainActivity extends AppCompatActivity implements IMainActivity,OnClickListener {
    private CartExpanableListview expanableListview;
    private String cartUrl = "https://www.zhaoapi.cn/product/getCarts?uid=3004";
    private CartPresenter cartPresenter;
    private Gson gson;
    private MyAdapter myAdapter;
    private CheckBox check_all;
    private TextView text_total;
    private TextView text_buy;

    private Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            if (msg.what == 0){
                CountPriceBean countPriceBean = (CountPriceBean) msg.obj;

                //设置
                text_total.setText("合计:¥"+countPriceBean.getPrice());
                text_buy.setText("去结算("+countPriceBean.getCount()+")");
            }else  if (msg.what == 1){//改变全选
                boolean flag = (boolean) msg.obj;

                check_all.setChecked(flag);
            }
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        check_all = (CheckBox) findViewById(R.id.check_all);
        text_total = (TextView) findViewById(R.id.text_total);
        text_buy = (TextView) findViewById(R.id.text_buy);
        expanableListview = (CartExpanableListview) findViewById(R.id.expanable_listview);
        //去掉默认的指示器
        expanableListview.setGroupIndicator(null);

        cartPresenter = new CartPresenter(this);
        gson = new Gson();

        //全选:...点击事件
        check_all.setOnClickListener(this);
    }

    @Override
    protected void onResume() {
        super.onResume();
        //请求数据
        cartPresenter.getCartData(cartUrl);
    }

    @Override
    public void getSuccessCartData(String json) {
        //解析数据
        CartBean cartBean = gson.fromJson(json, CartBean.class);
        //一个是一级标题的数据
        List<CartBean.DataBean> listGroup = cartBean.getData();
        //所有子条目的数据
        List<List<CartBean.DataBean.ListBean>> listChilds = new ArrayList<>();
        for (int i=0;i<listGroup.size();i++){
            listChilds.add(listGroup.get(i).getList());
        }

        //设置适配器
        myAdapter = new MyAdapter(MainActivity.this, listGroup, listChilds,handler);
        expanableListview.setAdapter(myAdapter);
        //展开所有
        for (int i=0;i<listGroup.size();i++){
            expanableListview.expandGroup(i);
        }
    }

    @Override
    public void onClick(View view) {
        switch (view.getId()){
            case R.id.check_all:
                myAdapter.setIfCheckAll(check_all.isChecked());
                break;
        }
    }
}

//adapter文件MyAdapter

public class MyAdapter extends BaseExpandableListAdapter{
    private Handler handler;
    private Context context;
    private List<CartBean.DataBean> listGroup;
    private List<List<CartBean.DataBean.ListBean>> listChilds;
    public MyAdapter(Context context, List<CartBean.DataBean> listGroup, List<List<CartBean.DataBean.ListBean>> listChilds, Handler handler) {
        this.context = context;
        this.listGroup = listGroup;
        this.listChilds = listChilds;
        this.handler = handler;
    }

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

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

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

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

    @Override
    public View getGroupView(final int groupPosition, boolean b, View view, ViewGroup viewGroup) {
        GroupHolder holder;
        if (view == null){
            view = View.inflate(context, R.layout.group_item_layout,null);
            holder = new GroupHolder();

            holder.check_group = view.findViewById(R.id.check_group);
            holder.text_group = view.findViewById(R.id.text_group);

            view.setTag(holder);

        }else {
            holder = (GroupHolder) view.getTag();
        }

        final CartBean.DataBean dataBean = listGroup.get(groupPosition);
        //赋值
        holder.check_group.setChecked(dataBean.isGroupChecked());
        holder.text_group.setText(dataBean.getSellerName());

        //设置点击事件
        holder.check_group.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //2.1改变当前一级选中的状态
                dataBean.setGroupChecked(! dataBean.isGroupChecked());
                //2.2根据当前一级的状态,改变该组里面二级列表的状态
                changeChildState(groupPosition,dataBean.isGroupChecked());
                //2.3通过判断所有的一级组是否选中,来决定是否全选选中
                changeAllState(isAllGroupChecked());
                //2.4发送价格个数量:
                sendPriceAndCount();
                //刷新适配器
                notifyDataSetChanged();
            }
        });

        return view;
    }

    /**
     * 根据所有一级列表是否选中,确定外面的全选是否选中
     * @param allGroupChecked
     */
    private void changeAllState(boolean allGroupChecked) {
        Message msg = Message.obtain();
        msg.what =1;
        msg.obj = allGroupChecked;
        handler.sendMessage(msg);
    }

    /**
     * 所有的一级列表是否选中
     * @return
     */
    private boolean isAllGroupChecked() {
        for (int i=0;i<listGroup.size();i++){

            if (! listGroup.get(i).isGroupChecked()){
                return false;
            }
        }
        return true;
    }

    /**
     * 根据当前一级列表的状态,,,改变当前组中所有二级列表的状态
     * @param groupPosition
     * @param groupChecked
     */
    private void changeChildState(int groupPosition, boolean groupChecked) {
        List<CartBean.DataBean.ListBean> listBeans = listChilds.get(groupPosition);

        for (int i=0;i<listBeans.size();i++){
            listBeans.get(i).setSelected(groupChecked? 1:0);
        }
    }

    @Override
    public View getChildView(final int groupPosition, int childPosition, boolean b, View view, ViewGroup viewGroup) {
        ChildHolder holder;
        if (view == null){
            view = View.inflate(context, R.layout.child_item_layout,null);
            holder = new ChildHolder();

            holder.text_add = view.findViewById(R.id.text_add);
            holder.text_num = view.findViewById(R.id.text_num);
            holder.text_jian = view.findViewById(R.id.text_jian);
            holder.text_title = view.findViewById(R.id.text_title);
            holder.text_price = view.findViewById(R.id.text_price);
            holder.image_good = view.findViewById(R.id.image_good);
            holder.check_child = view.findViewById(R.id.check_child);

            view.setTag(holder);

        }else {
            holder = (ChildHolder) view.getTag();
        }

       //赋值
        final CartBean.DataBean.ListBean listBean = listChilds.get(groupPosition).get(childPosition);

        holder.text_num.setText(listBean.getNum()+"");//......注意
        holder.text_price.setText("¥"+listBean.getPrice());
        holder.text_title.setText(listBean.getTitle());
        //listBean.getSelected().....0false,,,1true
        //设置checkBox选中状态
        holder.check_child.setChecked(listBean.getSelected()==0? false:true);

        /*implementation 'com.github.bumptech.glide:glide:4.4.0'
        annotationProcessor 'com.github.bumptech.glide:compiler:4.4.0'*/
        Glide.with(context).load(listBean.getImages().split("\\|")[0]).into(holder.image_good);

        //设置点击事件
        holder.check_child.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //3.1点击改变当前子条目状态:....实际是改变当前的数据,,,刷新适配器
                listBean.setSelected(listBean.getSelected() ==0? 1:0);
                //3.2发送价钱和数量给界面显示
                sendPriceAndCount();
                //3.3判断当前子条目是否选中
                if (listBean.getSelected() == 1){
                    //判断一下当前组中所有的子条目是否全部选中
                    if (isAllChildSelected(groupPosition)){
                        //如果全部选中改变一下当前组的状态
                        changeGroupState(groupPosition,true);
                        //.确定是否改变全选
                        changeAllState(isAllGroupChecked());
                    }

                }else {
                    //如果没有选中改变一下当前组的状态
                    changeGroupState(groupPosition,false);
                    //.确定是否改变全选
                    changeAllState(isAllGroupChecked());
                }
                //刷新适配器
                notifyDataSetChanged();
            }
        });

        //加号:
        holder.text_add.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //改变当前位置 中商品的数量
                listBean.setNum(listBean.getNum()+1);
                //判断一下是否选中...计算价格数量
                if (listBean.getSelected() == 1){
                    sendPriceAndCount();
                }
                notifyDataSetChanged();
            }
        });

        //减号
        holder.text_jian.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                int num = listBean.getNum();
                if (num == 1){
                    return;
                }
                listBean.setNum(num -1);
                //判断是否选中
                if (listBean.getSelected() == 1){
                    sendPriceAndCount();
                }
                notifyDataSetChanged();
            }
        });
        return view;
    }

    /**
     * 改变当前组的状态
     * @param groupPosition
     * @param b
     */
    private void changeGroupState(int groupPosition, boolean b) {
        listGroup.get(groupPosition).setGroupChecked(b);
    }

    /**
     * 判断当前组中所有的二级是否选中
     * @param groupPosition
     * @return
     */
    private boolean isAllChildSelected(int groupPosition) {
        List<CartBean.DataBean.ListBean> listBeans = listChilds.get(groupPosition);
        for (int i=0;i<listBeans.size();i++){
            if (listBeans.get(i).getSelected() == 0){
                return false;
            }
        }
        return true;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;//子条目是否可以点击
    }

    /**
     * 设置是否全选
     * @param checked
     */
    public void setIfCheckAll(boolean checked) {
        for (int i = 0;i<listGroup.size();i++){
            CartBean.DataBean dataBean = listGroup.get(i);
            //设置组上面的checkBox是否选中
            dataBean.setGroupChecked(checked);

            List<CartBean.DataBean.ListBean> listBeans = dataBean.getList();
            for (int j = 0; j< listBeans.size(); j++){
                //改变是否选中的状态...数据应该变的是
                listBeans.get(j).setSelected(checked? 1:0);
            }
        }
        //计算价钱和数量并且发送到mainActivity显示
        sendPriceAndCount();
        //刷新适配器
        notifyDataSetChanged();
    }

    /**
     * 计算总价和数量,,,发送显示
     */
    private void sendPriceAndCount() {
        double price = 0;
        int count = 0;

        for (int i=0;i<listGroup.size();i++){
            List<CartBean.DataBean.ListBean> listBeans = listGroup.get(i).getList();
            for (int j = 0;j<listBeans.size();j++){

                CartBean.DataBean.ListBean listBean = listBeans.get(j);
                if (listBean.getSelected()==1){

                    price += listBean.getPrice()* listBean.getNum();
                    count += listBean.getNum();
                }
            }
        }

        CountPriceBean countPriceBean = new CountPriceBean(price, count);
        //显示到activity页面
        Message msg = Message.obtain();
        msg.what = 0;
        msg.obj = countPriceBean;
        handler.sendMessage(msg);
    }

    private class GroupHolder{
        CheckBox check_group;
        TextView text_group;
    }

    private class ChildHolder{
        CheckBox check_child;
        ImageView image_good;
        TextView text_title;
        TextView text_price;
        TextView text_jian;
        TextView text_num;
        TextView text_add;
    }
}

//application文件DashApplication

package com.bwie.test.application;

import android.app.Application;
import android.content.Context;
import android.os.Handler;
import android.os.Process;

public class DashApplication extends Application {
    private static Context context;
    private static Handler handler;
    private static int mainId;
    public static boolean isLoginSuccess;//是否已经登录的状态

    @Override
    public void onCreate() {
        super.onCreate();
        //关于context----http://blog.youkuaiyun.com/lmj623565791/article/details/40481055
        context = getApplicationContext();
        //初始化handler
        handler = new Handler();
        //主线程的id
        mainId = Process.myTid();
    }

    /**
     * 对外提供了context
     * @return
     */
    public static Context getAppContext() {
        return context;
    }

    /**
     * 得到全局的handler
     * @return
     */
    public static Handler getAppHanler() {
        return handler;
    }

    /**
     * 获取主线程id
     * @return
     */
    public static int getMainThreadId() {
        return mainId;
    }
}

//bean文件CartBean

public class CartBean {
    private String msg;
    private String code;
    private List<DataBean> 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<DataBean> getData() {
        return data;
    }

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

    public static class DataBean {
        public boolean isGroupChecked() {
            return isGroupChecked;
        }

        public void setGroupChecked(boolean groupChecked) {
            isGroupChecked = groupChecked;
        }

        private boolean isGroupChecked;
        private String sellerName;
        private String sellerid;
        private List<ListBean> 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<ListBean> getList() {
            return list;
        }

        public void setList(List<ListBean> 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;
            }
        }
    }
}

//CountPriceBean

public class CountPriceBean {
    private double price;
    private int count;

    public CountPriceBean(double price, int count) {
        this.price = price;
        this.count = count;
    }

    public double getPrice() {
        return price;
    }

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

    public int getCount() {
        return count;
    }

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