购物车逻辑:

依赖

//MetrialDesign:Design库
    implementation 'com.android.support:design:28.+'
    //Butterknife:根据反射注入框架
    implementation 'com.jakewharton:butterknife:8.8.1'
    annotationProcessor 'com.jakewharton:butterknife-compiler:8.8.1'
    //Brvah：RecyclerView快速开发框架
    implementation 'com.github.CymChad:BaseRecyclerViewAdapterHelper:2.9.30'
    //SmartRefreshLayout
    implementation 'com.scwang.smartrefresh:SmartRefreshLayout:1.1.0-alpha-19'
    implementation 'com.scwang.smartrefresh:SmartRefreshHeader:1.1.0-alpha-19'
    //没有使用特殊Header，可以不加这行
    //okgo
    //必须使用
    implementation 'com.lzy.net:okgo:3.0.4'
    implementation 'com.google.code.gson:gson:2.8.5'
    //图片加载框架
    implementation 'com.github.bumptech.glide:glide:4.8.0'
    annotationProcessor 'com.github.bumptech.glide:compiler:4.8.0'

//activity

public class ShopActivity extends AppCompatActivity implements IShopContract.IShopView, View.OnClickListener {

    @BindView(R.id.m_recycler)
    RecyclerView mRecycler;
    @BindView(R.id.m_clok)
    CheckBox mClok;
    @BindView(R.id.m_btn_price)
    Button mBtnPrice;
    @BindView(R.id.m_tv_count)
    TextView mTvCount;
    private ShopPresenter presenter;
    private List<ShopBean.DataBean> dataBean;
    private Context mContext;
    private MyQnameBaseAdapter qnameBaseAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);
        mContext = ShopActivity.this;
        presenter = new ShopPresenter();
        presenter.attachView(this);
        //动作
        presenter.requestData();

    }

    @Override
    public void showLoading() {

    }

    @Override
    public void hideLoading() {

    }

    @Override
    public void showData(String urlString) {
        //
        mClok.setOnCheckedChangeListener(null);
        //全选处理
        mClok.setOnClickListener(this);

        //解析
        Gson gson = new Gson();
        ShopBean shopBean = gson.fromJson(urlString, ShopBean.class);
        dataBean = shopBean.getData();

        //设置布局管理器
        LinearLayoutManager manager = new LinearLayoutManager(mContext, LinearLayoutManager.VERTICAL, false);
        mRecycler.setLayoutManager(manager);
        //设置适配器
        qnameBaseAdapter = new MyQnameBaseAdapter(R.layout.item_name_sj, dataBean);
        mRecycler.setAdapter(qnameBaseAdapter);
        //
        qnameBaseAdapter.setOnNameClickLisenter(new MyQnameBaseAdapter.OnNameClickLisenter() {
            @Override
            public void onCallBack() {
                boolean reslt = true;
                for (int i = 0; i < dataBean.size(); i++) {
                    //外层选中状态
                    boolean nameCheckedd = dataBean.get(i).getNameCheckedd();
                    reslt = reslt & nameCheckedd;
                    for (int j = 0; j < dataBean.get(i).getList().size(); j++) {
                        //内层选中状态
                        boolean goodsChecked = dataBean.get(i).getList().get(j).getGoodsChecked();
                        reslt = reslt & goodsChecked;
                    }
                }
                mClok.setChecked(reslt);
                //计算价格
                calcuCount();

            }
        });


    }

    private void calcuCount() {
        double totCount = 0;
        for (int i = 0; i < dataBean.size(); i++) {
            for (int j = 0; j < dataBean.get(i).getList().size(); j++) {
                //判断内层条目是否勾选
                if (dataBean.get(i).getList().get(j).getGoodsChecked()){
                    double price = dataBean.get(i).getList().get(j).getPrice();
                    int sumTet = dataBean.get(i).getList().get(j).getSumTet();

                    double goodsprice = price * sumTet;

                    totCount = totCount + goodsprice;
                }
            }

        }
        mTvCount.setText("总价是:"+String.valueOf(totCount));
    }


    @Override
    protected void onDestroy() {
        super.onDestroy();
        presenter.detachView(this);
    }

    //全选点击触发事件
    @Override
    public void onClick(View v) {
        //全选处理
        for (int i = 0; i < dataBean.size(); i++) {
            dataBean.get(i).setNameChecked(mClok.isChecked());
            for (int j = 0; j < dataBean.get(i).getList().size(); j++) {
                dataBean.get(i).getList().get(j).setGoodsChecked(mClok.isChecked());
            }
        }
        //适配器刷新
        qnameBaseAdapter.notifyDataSetChanged();

        //计算价格
        calcuCount();
    }
}

//activity 对应的Xml布局

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ui.activity.ShopActivity"
    android:orientation="vertical">

    <android.support.v7.widget.Toolbar
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/colorPrimaryDark"
        android:fitsSystemWindows="true"
        app:title="@string/toolbar_name" />


    <com.scwang.smartrefresh.layout.SmartRefreshLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/m_recycler"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            />
    </com.scwang.smartrefresh.layout.SmartRefreshLayout>

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:gravity="center_vertical">


        <CheckBox
            android:id="@+id/m_clok"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:text="全选" />


        <Button
            android:id="@+id/m_btn_price"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_alignParentRight="true"
            android:gravity="center_vertical"
            android:paddingLeft="20dp"
            android:paddingRight="20dp"
            android:text="结算" />

        <TextView
            android:id="@+id/m_tv_count"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_marginRight="20dp"
            android:layout_toLeftOf="@+id/m_btn_price"
            android:gravity="center_vertical"
            android:text="总计:0元" />
    </RelativeLayout>

</LinearLayout>

//商家条目 : Adapter

public class MyQnameBaseAdapter extends BaseQuickAdapter<ShopBean.DataBean,BaseViewHolder> {

    /*____________接口回调________*/
    OnNameClickLisenter nameClickLisenter;

    public interface OnNameClickLisenter{
        public void onCallBack();
    }

    public void setOnNameClickLisenter(OnNameClickLisenter nameClickLisenter){
        this.nameClickLisenter = nameClickLisenter;
    }

    /*____________________________*/

    public MyQnameBaseAdapter(int layoutResId, @Nullable List<ShopBean.DataBean> data) {
        super(layoutResId, data);
    }

    @Override
    protected void convert(BaseViewHolder helper, final ShopBean.DataBean item) {
        helper.setText(R.id.sj_name,item.getSellerName());
        //商品条目  控件
        RecyclerView goodsRecyclerView = helper.getView(R.id.sj_rv_goods);

        //避免焦点抢占
        final CheckBox nameCheckBox = helper.getView(R.id.sj_ck_xz);
        nameCheckBox.setOnCheckedChangeListener(null);
        //获取商家条目是否选中状态
        nameCheckBox.setChecked(item.getNameCheckedd());

        //数据
        List<ShopBean.DataBean.ListBean> listBeans = item.getList();
        //设置布局管理器
        LinearLayoutManager manager = new LinearLayoutManager(mContext, LinearLayoutManager.VERTICAL, false);
        goodsRecyclerView.setLayoutManager(manager);
        //设置适配器
        final MyGoodsAdapter goodsAdapter = new MyGoodsAdapter(R.layout.item_goods_sp,listBeans);
        goodsRecyclerView.setAdapter(goodsAdapter);


        //商品条目控制 商家条目
        goodsAdapter.setOnGoodsClickLisenter(new MyGoodsAdapter.OnGoodsClickLisenter() {
            @Override
            public void onCallBack() {
                boolean reslt = true;
                //遍历获取所有子条目，只要有一个未勾选，商品类别也应该是未勾选
                for (int i = 0; i < item.getList().size(); i++) {
                    boolean goodsChecked = item.getList().get(i).getGoodsChecked();
                    reslt = reslt & goodsChecked;
                }
                nameCheckBox.setChecked(reslt);
                //刷新
                goodsAdapter.notifyDataSetChanged();
                //回传状态
                nameClickLisenter.onCallBack();

            }
        });

        //商家条目控制商品天目
        nameCheckBox.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                for (int i = 0; i < item.getList().size(); i++) {
                    item.getList().get(i).setGoodsChecked(nameCheckBox.isChecked());
                }
                item.setNameChecked(nameCheckBox.isChecked());
                //刷新
                notifyDataSetChanged();
                //回传状态
                nameClickLisenter.onCallBack();
            }
        });


    }
}

//商家条目 对应的Xml布局

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    tools:context=".ui.activity.ShopActivity"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <CheckBox
            android:id="@+id/sj_ck_xz"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:gravity="center" />

        <TextView
            android:id="@+id/sj_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:gravity="center"
            android:paddingLeft="5dp"
            android:text="店名"
            android:textSize="22sp" />
    </LinearLayout>r

    <android.support.v7.widget.RecyclerView
        android:id="@+id/sj_rv_goods"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

//商品条目 Adapter

public class MyGoodsAdapter extends BaseQuickAdapter<ShopBean.DataBean.ListBean,BaseViewHolder> {

    /*____________接口回调________*/
    OnGoodsClickLisenter goodsClickLisenter;
    public interface OnGoodsClickLisenter{
        public void onCallBack();
    }

    public void setOnGoodsClickLisenter(OnGoodsClickLisenter goodsClickLisenter){
        this.goodsClickLisenter = goodsClickLisenter;
    }


    /*____________________________*/


    public MyGoodsAdapter(int layoutResId, @Nullable List<ShopBean.DataBean.ListBean> data) {
        super(layoutResId, data);
    }

    @Override
    protected void convert(BaseViewHolder helper, final ShopBean.DataBean.ListBean item) {
        helper.setText(R.id.goods_name,item.getTitle());
        helper.setText(R.id.goods_price,"$:"+item.getPrice());
        //获取控件
        ImageView iv_goodsIcon = helper.getView(R.id.sp_goods_image);
        //获取url值并剪切
        String imagesString = item.getImages();
        String[] imagesStr = imagesString.split("\\|");
        //给控件图片
        Glide.with(mContext).load(imagesStr[0]).into(iv_goodsIcon);
        //避免焦点抢占
        CheckBox cb_goods = helper.getView(R.id.cb_goods);
        cb_goods.setOnCheckedChangeListener(null);
        cb_goods.setChecked(item.getGoodsChecked());
        //使用接口把状态回传
        cb_goods.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

                item.setGoodsChecked(isChecked);

                goodsClickLisenter.onCallBack();

            }
        });

        //获取自定义Viwe控件
        CalculatorView calculatorView = helper.getView(R.id.sp_price_cal);
        //
        calculatorView.setOnCalculatorLisenter(new CalculatorView.OnCalculatorLisenter() {
            @Override
            public void OnJian(int number) {
                //对新增的字段进行改动
                item.setSumTet(number);
                goodsClickLisenter.onCallBack();
            }

            @Override
            public void OnAdd(int number) {
                //对新增的字段进行改动
                item.setSumTet(number);
                goodsClickLisenter.onCallBack();
            }
        });

    }
}

//商品条目 对应的xml布局

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    tools:context=".ui.activity.ShopActivity"
    android:orientation="vertical">


    <android.support.v7.widget.CardView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="20dp"
        android:layout_marginTop="@dimen/dp_10"
        app:cardCornerRadius="@dimen/dp_4"
        app:contentPaddingBottom="@dimen/dp_4">


        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:layout_margin="10dp">

            <CheckBox
                android:id="@+id/cb_goods"
                android:layout_width="wrap_content"
                android:layout_height="80dp"
                android:layout_centerVertical="true" />

            <ImageView
                android:id="@+id/sp_goods_image"
                android:layout_width="80dp"
                android:layout_height="80dp"
                android:layout_toRightOf="@id/cb_goods"
                android:paddingLeft="5dp"
                android:src="@mipmap/ic_launcher" />

            <LinearLayout
                android:layout_toRightOf="@id/sp_goods_image"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerHorizontal="true"
                android:orientation="vertical">

                <TextView
                    android:id="@+id/goods_name"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:ellipsize="end"
                    android:hint="商品名称"
                    android:maxEms="20"
                    android:paddingLeft="5dp"
                    android:textStyle="bold" />

                <TextView
                    android:gravity="center"
                    android:id="@+id/goods_price"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_below="@id/goods_name"
                    android:layout_marginTop="@dimen/dp_10"
                    android:hint="商品价格" />


                <gxq.com.shopping001.ui.widget.CalculatorView
                    android:id="@+id/sp_price_cal"
                    android:layout_width="wrap_content"
                    android:layout_gravity="center"
                    android:layout_height="wrap_content"></gxq.com.shopping001.ui.widget.CalculatorView>

            </LinearLayout>




        </LinearLayout>
    </android.support.v7.widget.CardView>

</LinearLayout>

//自定义View加减器
Xml布局

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    tools:context=".ui.activity.ShopActivity"
    android:orientation="horizontal">

    <Button
        android:id="@+id/but_jian"
        android:layout_width="@dimen/dp_40"
        android:layout_height="@dimen/dp_40"
        android:padding="@dimen/dp_10"
        android:background="@mipmap/decrease"/>

    <TextView
        android:id="@+id/tv_numb"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@null"
        android:inputType="number"
        android:text="1"/>

    <Button
        android:id="@+id/but_jia"
        android:layout_width="@dimen/dp_40"
        android:layout_height="@dimen/dp_40"
        android:padding="@dimen/dp_10"
        android:background="@mipmap/add"/>



</LinearLayout>

//实现

public class CalculatorView extends LinearLayout implements View.OnClickListener {

    private final Button but_jian;
    private final Button but_jia;
    private final TextView tv_numb;

    public CalculatorView(Context context, AttributeSet attrs) {
        super(context, attrs);
        View rootView = LayoutInflater.from(context).inflate(R.layout.sp_jia_jian, this);
        but_jian = rootView.findViewById(R.id.but_jian);
        but_jia = rootView.findViewById(R.id.but_jia);
        tv_numb = rootView.findViewById(R.id.tv_numb);
        ////
        but_jian.setOnClickListener(this);
        but_jia.setOnClickListener(this);

    }

    @Override
    public void onClick(View v) {
        String numberString = tv_numb.getText().toString();
        int number = Integer.parseInt(numberString);

        switch (v.getId()){
            case R.id.but_jian:
                number = number - 1;
                if(number<0){
                    number=0;
                    //  最小数量为0
                    tv_numb.setText(String.valueOf(number));
                }
                //赋值
                tv_numb.setText(String.valueOf(number));
                //接口回调
                calculatorLisenter.OnJian(number);
                break;
            case R.id.but_jia:
                number = number + 1;
                //赋值
                tv_numb.setText(String.valueOf(number));
                //接口回调
                calculatorLisenter.OnAdd(number);
                break;
        }
    }

    /*________ 接口回调  ______*/

    OnCalculatorLisenter calculatorLisenter;

    public interface OnCalculatorLisenter{
        public void OnJian(int number);
        public void OnAdd(int number);
    }

    public void setOnCalculatorLisenter(OnCalculatorLisenter calculatorLisenter){
        this.calculatorLisenter = calculatorLisenter;
    }
    /*_____________________*/

}

//效果图