购物车原理：

//

首先购物车是一个二级列表，因为，二级列表的一级列表代表商店，二级列表代表要购买的东西。

所以你要用到的知识点就是：

 ExpandableListView 

但是这个控件有一个缺点，不能进行滚动。所以要想解决这个缺点，需要和scrollview结合起来。但和scrollview结合起来使用的时候，expandablelistview的高度只会显示一个。需要系定义控件：如下

public class CustomExpandableListView extends ExpandableListView {
    public CustomExpandableListView(Context context, AttributeSet attrs) {
        super(context, attrs);
        // TODO Auto-generated constructor stub
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        // TODO Auto-generated method stub
        int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2,
                MeasureSpec.AT_MOST);
        super.onMeasure(widthMeasureSpec, expandSpec);
    }

}

布局使用情况如下：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >

    <ScrollView
        android:layout_width="match_parent"
        android:layout_marginBottom="50dp"
        android:layout_height="match_parent">

        <lianxi.bawei.com.gouwuche.view.CustomExpandableListView
            android:id="@+id/elist"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

        </lianxi.bawei.com.gouwuche.view.CustomExpandableListView>

    </ScrollView>


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_alignParentBottom="true"
        android:background="@android:color/white"
        android:gravity="center_vertical"
        android:orientation="horizontal"
        >

        <CheckBox
            android:id="@+id/checkbox2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="10dp"
            android:layout_marginTop="6dp"
            android:button="@drawable/select_checkbox"
            android:focusable="false"/>

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="10dp"
            android:layout_marginTop="6dp"
            android:text="全选"
            android:textSize="20sp"/>

        <TextView
            android:id="@+id/tv_num"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="10dp"
            android:layout_marginTop="6dp"

            android:text="0台"/>

        <TextView
            android:id="@+id/tv_price"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="10dp"
            android:layout_marginTop="6dp"
            android:text="0元"/>
    </LinearLayout>
</RelativeLayout>

//然后在manactivity里进行逻辑：

package lianxi.bawei.com.gouwuche.activity;

import android.database.DataSetObserver;
import android.support.v4.view.PagerAdapter;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.TextView;

import com.google.gson.Gson;
import com.squareup.okhttp.Call;
import com.squareup.okhttp.Callback;
import com.squareup.okhttp.FormEncodingBuilder;
import com.squareup.okhttp.OkHttpClient;
import com.squareup.okhttp.Request;
import com.squareup.okhttp.Response;

import java.io.IOException;
import java.util.List;

import lianxi.bawei.com.gouwuche.Bean.PhonesInfo;
import lianxi.bawei.com.gouwuche.R;
import lianxi.bawei.com.gouwuche.view.CustomExpandableListView;

import static lianxi.bawei.com.gouwuche.R.id.elist;

public class MainActivity extends AppCompatActivity {


    private CheckBox checkBox;
    private TextView tv_num;
    private TextView tv_price;

    private List<PhonesInfo.DataInfo> data;
    private PhonesInfo phonesInfo;
    private CustomExpandableListView elist;
    private PhoneAdapter p1;
    int price=0;
    int num=0;
    int price1;
    int num1;

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

        postdata();


    }

    private void postdata() {

        OkHttpClient okHttpClient = new OkHttpClient();
        String url = "http://api.ehuigou.com/Orders/searchCartsLog";
        FormEncodingBuilder builder = new FormEncodingBuilder();
        builder.add("store_id", "3850");

        Request request = new Request.Builder().url(url).post(builder.build()).build();
        Call call = okHttpClient.newCall(request);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(Request request, IOException e) {

            }

            @Override
            public void onResponse(Response response) throws IOException {

                final String string = response.body().string();
                Log.i("xxx", string.toString());
                   runOnUiThread(new Runnable() {




                       @Override
                       public void run() {
                           Gson g1=new Gson();
                           phonesInfo= g1.fromJson(string, PhonesInfo.class);
                           Log.i("kkkkkk", phonesInfo.getData().size()+"");
                          // data = phonesInfo.getData();
                           //Log.i("aaa",data.toString());
                           p1 = new PhoneAdapter();
                           elist.setAdapter(p1);
                           int count = elist.getCount();
                           for (int i = 0; i < count; i++) {
                               elist.expandGroup(i);
                           }

                           checkBox.setOnClickListener(new View.OnClickListener() {
                               @Override
                               public void onClick(View v) {
                                   boolean falg = ((CheckBox) v).isChecked();

                              checkBox.setChecked(falg);
  //判断boolean类型，如果为true，则都设置为true
 if(falg==true)
                                   {
                                  //每次让它为初始值，这样价格不会乱序
                                   num=0;
                                       price=0;
                                       List<PhonesInfo.DataInfo> data = phonesInfo.data;
                                       for (int i=0;i<data.size();i++)
                                       {

                                           data.get(i).setAllCheck(falg);
                                           List<PhonesInfo.DataInfo.DatasInfo> datas = data.get(i).getDatas();
                                           num=num+datas.size();
                                           num1=num;
                                           for (int j=0;j<datas.size();j++)
                                               {

                                                   price=price+datas.get(j).getPrice();
                                                   price1=price;
                                                   datas.get(j).setItemCheck(falg);
                                               }
                                             //这是台数，和价格
                                          tv_num.setText(num+"台");
                                           tv_price.setText(price+"元");


                                       }




                                   }
                                       //这是false的逻辑
                                          else{
                                       List<PhonesInfo.DataInfo> data = phonesInfo.data;
                                       for (int i=0;i<data.size();i++)
                                       {
                                           data.get(i).setAllCheck(false);
                                           List<PhonesInfo.DataInfo.DatasInfo> datas = data.get(i).getDatas();
                                           for (int j=0;j<datas.size();j++)
                                           {
                                               datas.get(j).setItemCheck(false);
                                           }
                                       }
                                       num=0;
                                       price=0;
                                       tv_num.setText(num+"台");
                                       tv_price.setText(price+"元");
                                   }
                                   refresh();
                               }
                           });

                         /*  checkBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
                               @Override
                               public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                                   if(isChecked==true)
                                   {

                                       tv_num.setText(num1+"台");
                                       tv_price.setText(price1+"元");

                                   }

                               }
                           });*/


                       }
                   });

            }
        });
    }

    private void initview() {
        elist = (CustomExpandableListView) findViewById(R.id.elist);
        checkBox = (CheckBox) findViewById(R.id.checkbox2);
        tv_num = (TextView) findViewById(R.id.tv_num);
        tv_price = (TextView) findViewById(R.id.tv_price);
    }


    class PhoneAdapter implements ExpandableListAdapter {

        @Override
        public void registerDataSetObserver(DataSetObserver observer) {

        }

        @Override
        public void unregisterDataSetObserver(DataSetObserver observer) {

        }

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

        @Override
        public int getChildrenCount(int groupPosition) {
            return phonesInfo.getData().get(groupPosition).getDatas().size();
        }

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

        @Override
        public Object getChild(int groupPosition, int childPosition) {
            return phonesInfo.getData().get(groupPosition).getDatas().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 convertView, ViewGroup parent) {
            View view = View.inflate(MainActivity.this, R.layout.item_parent_market, null);
            CheckBox cb_parent = (CheckBox) view.findViewById(R.id.cb_parent);
            TextView tv_number = (TextView) view.findViewById(R.id.tv_number);
            tv_number.setText(phonesInfo.getData().get(groupPosition).getTitle());
            cb_parent.setChecked(phonesInfo.getData().get(groupPosition).isAllCheck());


                 cb_parent.setOnClickListener(new View.OnClickListener() {

                     private boolean h=true;

                     @Override
                     public void onClick(View v) {
                         //一级列表的状态
                         boolean falg = ((CheckBox) v).isChecked();
                         //给一级列表赋值
                         phonesInfo.getData().get(groupPosition).setAllCheck(falg);
                         //判断状态
                         if (falg == true) {
                             Log.i("jjjj", falg + "");
                             //给二级列表的所有都赋值
                             List<PhonesInfo.DataInfo.DatasInfo> datas = phonesInfo.data.get(groupPosition).getDatas();
                             //让二级列表的所有都为true

for (int i=0;i<datas.size();i++)
{
    if(datas.get(i).isItemCheck()==true)
    {

        price=price-datas.get(i).getPrice();
        num=num-1;
    }
}
 num=num+datas.size();                             for (int i = 0; i < datas.size(); i++) {                                 datas.get(i).setItemCheck(true);                                 price=price+datas.get(i).getPrice();                                 refresh();                             }                             tv_num.setText(num+"台");                             tv_price.setText(price+"元");                             //判断一级级列表里面的东西是不是都是true                             for (int i=0;i<phonesInfo.data.size();i++)                             {                                 if(phonesInfo.data.get(i).isAllCheck()==false)                                 {                                     h=false;                                 }                             }                            //如果是true,就赋值给checkbox                             if(h==true)                             {                                 checkBox.setChecked(true);                             }                         }                         //判断一级列表的状态，有一个是false,总的就是false                         else if (falg == false) {                             checkBox.setChecked(falg);                             //下面的方法：是，一级列表的反选                             List<PhonesInfo.DataInfo.DatasInfo> datas = phonesInfo.data.get(groupPosition).getDatas();                                 num=num-datas.size();                             for (int i = 0; i < datas.size(); i++) {                                 datas.get(i).setItemCheck(false);                                 price=price-datas.get(i).getPrice();                             }                             //当那个为fals时，减去那个价钱                             tv_price.setText(price+"元");                             tv_num.setText(num+"台");                         }                         refresh();                     }                 });            return view;        }        @Override        public View getChildView(final int groupPosition, final int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {            View view = View.inflate(MainActivity.this, R.layout.item_child_market, null);            TextView tv_content = (TextView) view.findViewById(R.id.tv_content);            TextView tv_time = (TextView) view.findViewById(R.id.tv_time);            TextView tv_pri = (TextView) view.findViewById(R.id.tv_pri);            CheckBox cb_child = (CheckBox) view.findViewById(R.id.cb_child);            tv_pri.setText(phonesInfo.getData().get(groupPosition).getDatas().get(childPosition).getPrice() + "元");            tv_content.setText(phonesInfo.getData().get(groupPosition).datas.get(childPosition).getType_name());            cb_child.setChecked(phonesInfo.getData().get(groupPosition).datas.get(childPosition).isItemCheck());                         cb_child.setOnClickListener(new View.OnClickListener() {                             private Boolean j;                             @Override                             public void onClick(View v) {                                 //二级列表的状态                                 boolean falg = ((CheckBox) v).isChecked();                                 //直接赋值                                 phonesInfo.getData().get(groupPosition).datas.get(childPosition).setItemCheck(falg);                                 //得到当前二级列表的集合                                 List<PhonesInfo.DataInfo.DatasInfo> datas = phonesInfo.getData().get(groupPosition).getDatas();                                  Boolean f=true;                                 Boolean s=true;                                 //判断状态                                 if(falg==false)                                      {                                          num=num-1;                                          price=price-  phonesInfo.getData().get(groupPosition).datas.get(childPosition).getPrice();                                          //假如有一个是false,一级列表的就是false,全选也是false                                          phonesInfo.getData().get(groupPosition).setAllCheck(false);                                          checkBox.setChecked(falg);                                          tv_num.setText(num+"台");                                          tv_price.setText(price+"元");                                      }                                 //当二级都选中的时候，分两种，一种是：全都选中，一种是一级列表中的二级列表全选中                                 else if(falg==true){                                              num=num+1;                                     price=price+phonesInfo.getData().get(groupPosition).datas.get(childPosition).getPrice();                                     tv_num.setText(num+"台");                                     tv_price.setText(price+"元");                                     //第一个判断的就是，一级列表中的二级列表是否全选中                                     for(int i=0;i<datas.size();i++)                                     {                                         if(datas.get(i).isItemCheck()==false)                                         {                                             f=false;                                         }                                     }                                     if(f==true)                                     {                                         phonesInfo.getData().get(groupPosition).setAllCheck(true);                                     }                                      //这个是：全都选中，                                     for (int i=0;i<phonesInfo.data.size();i++)                                     {                                         List<PhonesInfo.DataInfo.DatasInfo> datas1 = phonesInfo.data.get(i).getDatas();                                         if(phonesInfo.data.get(i).isAllCheck()==false)                                         {                                             s=false;                                         }                                     }                                     if(s==true)                                     {                                         checkBox.setChecked(true);                                     }                                 }                                 refresh();                             }                         });            return view;        }        @Override        public boolean isChildSelectable(int groupPosition, int childPosition) {            return true;        }        @Override        public boolean areAllItemsEnabled() {            return false;        }        @Override        public boolean isEmpty() {            return false;        }        @Override        public void onGroupExpanded(int groupPosition) {        }        @Override        public void onGroupCollapsed(int groupPosition) {        }        @Override        public long getCombinedChildId(long groupId, long childId) {            return 0;        }        @Override        public long getCombinedGroupId(long groupId) {            return 0;        }    }    public void refresh() {        p1 = new PhoneAdapter();        elist.setAdapter(p1);        int count = elist.getCount();        for (int i = 0; i < count; i++) {            elist.expandGroup(i);        }    }}

对了，这个控件没有刷新，需要定义一个方法：来进行刷新

 public void refresh() {
        p1 = new PhoneAdapter();
        elist.setAdapter(p1);
        int count = elist.getCount();
        for (int i = 0; i < count; i++) {
            elist.expandGroup(i);
        }
    }

//下面的是bean包：

package lianxi.bawei.com.gouwuche.Bean;

import java.util.List;

/**
 * 1. 类的用途
 * 2. @author forever
 * 3. @date 2017/4/9 17:10
 */

public class PhonesInfo {
    public String flag;
    public String code;
    public List<DataInfo> data;

    public String getFlag() {
        return flag;
    }

    public void setFlag(String flag) {
        this.flag = flag;
    }

    public String getCode() {
        return code;
    }

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

    public List<DataInfo> getData() {
        return data;
    }

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

    public static  class DataInfo {
        public String title;
        public List<DatasInfo> datas;
        private boolean allCheck = false;


        public String getTitle() {
            return title;
        }

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

        public List<DatasInfo> getDatas() {
            return datas;
        }

        public void setDatas(List<DatasInfo> datas) {
            this.datas = datas;
        }

        public boolean isAllCheck() {
            return allCheck;
        }

        public void setAllCheck(boolean allCheck) {
            this.allCheck = allCheck;
        }

        public static class DatasInfo {
            private int price;
            private String type_name;
            private List<String> msg;
            private String add_time;
            private boolean itemCheck=false;


            public int getPrice() {
                return price;
            }

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

            public String getType_name() {
                return type_name;
            }

            public void setType_name(String type_name) {
                this.type_name = type_name;
            }

            public List<String> getMsg() {
                return msg;
            }

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

            public String getAdd_time() {
                return add_time;
            }

            public void setAdd_time(String add_time) {
                this.add_time = add_time;
            }

            public boolean isItemCheck() {
                return itemCheck;
            }

            public void setItemCheck(boolean itemCheck) {
                this.itemCheck = itemCheck;
            }
        }
        }




    @Override
    public String toString() {
        return "PhonesInfo{" +
                "flag='" + flag + '\'' +
                ", code='" + code + '\'' +
                ", data=" + data +
                '}';
    }
}

//下面是二级列表和一级列表的布局：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:background="@android:color/holo_red_light"
              android:gravity="center_vertical"
              android:orientation="horizontal"
    android:descendantFocusability="blocksDescendants"
    >

    <CheckBox

        android:id="@+id/cb_child"
        android:layout_width="wrap_content"

        android:button="@drawable/select_checkbox"
        android:layout_marginTop="30dp"
        android:layout_marginLeft="30dp"
        android:layout_marginBottom="30dp"
        android:layout_height="wrap_content"/>

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <TextView
            android:id="@+id/tv_tel"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="20dp"
            android:text="iphone6"/>

        <TextView
            android:id="@+id/tv_content"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="20dp"
            android:text="什么手机"/>

        <TextView
            android:id="@+id/tv_time"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="20dp"
            android:text="2016-12-10"/>
    </LinearLayout>

    <TextView
        android:id="@+id/tv_pri"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="¥3000.00"
        android:layout_marginLeft="30dp"
        />
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="100dp"
              android:gravity="center_vertical"
              android:orientation="horizontal"
    >

    <CheckBox

        android:id="@+id/cb_parent"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="30dp"

        android:focusable="false"
        android:layout_marginBottom="30dp"
        android:button="@drawable/select_checkbox"
        android:layout_marginLeft="50dp"/>

    <TextView
        android:id="@+id/tv_sign"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="20dp"
        android:text="标记"/>

    <TextView
        android:id="@+id/tv_number"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="20dp"
        android:text="12345678"/>

</LinearLayout>