Android仿淘宝购物车

【参考借鉴】Android仿淘宝购物车，玩转电商购物车

首先看一下效果

购物车主要由ExpandableListView来实现，其中逻辑比较复杂的是价钱与各个操作之间的交互，掌握的交互就掌握了购物车的原理。

11111.png 222.png

实现过程

1.配置group与child的item布局文件。记住要设置group不可展开。

item_group.xml的配置如下：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/backgroundWhite">

    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:paddingLeft="@dimen/toolbar_padLeft">

        <CheckBox
            android:id="@+id/item_shopcart_group_checkBox"
            style="@style/Shopcart_Checkbox_Style" />
        <TextView
            android:layout_marginLeft="@dimen/toolbar_padLeft"
            style="@style/Shopcart_shopName_Style"
            android:text="赵同学店铺"
            android:id="@+id/item_shopcart_group_nameTv"/>
        <Button
            android:id="@+id/item_shopcart_group_editBtn"
            style="@style/Shopcart_EditBtn_Style"
            android:text="编辑" />
    </LinearLayout>

</RelativeLayout>

item_child.xml的配置如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@color/backgroundWhite">

    <LinearLayout
        android:gravity="center_vertical"
        android:paddingLeft="@dimen/toolbar_padLeft"
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <CheckBox
            android:id="@+id/item_shopcart_child_checkBox"
            style="@style/Shopcart_Checkbox_Style"/>

        <!--图片的paddingTom与paddingBotton与内容布局的一样：如需修改，请注意-->
        <ImageView
            android:layout_marginLeft="@dimen/toolbar_padLeft"
            style="@style/Shopcart_Good_img_Style"
            android:id="@+id/item_shopcart_child_goods_image"
            android:src="@mipmap/goods_img"/>
        <!--未编辑时的布局-->
        <LinearLayout
            android:id="@+id/item_shopcart_child_goods_data_noedit"
            android:paddingBottom="@dimen/toolbar_padLeft"
            android:orientation="vertical"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:paddingRight="@dimen/padding_top">

            <TextView
                style="@style/Shopcart_Good_title_Style"
                android:text="雅诗兰黛气垫保湿遮瑕裸妆防水清爽防晒不脱妆"
                android:id="@+id/item_shopcart_child_goods_name"/>
            <TextView
                style="@style/Shopcart_Good_Size_Style"
                android:id="@+id/item_shopcart_child_goods_size"
                android:text="规格：小猪  黄色"/>
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="0dp"
                android:layout_weight="1"/>
            <LinearLayout
                android:orientation="horizontal"
                android:gravity="center_vertical"
                android:layout_width="match_parent"
                android:layout_height="wrap_content">
                <TextView
                    style="@style/Shopcart_Good_Price_Style"
                    android:id="@+id/item_shopcart_child_goods_price"
                    android:text="￥100.00" />
                <TextView
                    style="@style/Shopcart_Good_Count_Style"
                    android:text="x1"
                    android:textSize="24px"
                    android:id="@+id/item_shopcart_child_goods_buyNum"/>
            </LinearLayout>
        </LinearLayout>

        <!--编辑时的布局-->
        <LinearLayout
            android:visibility="gone"
            android:id="@+id/item_shopcart_child_edit_goods_data"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="horizontal">

            <LinearLayout
                android:layout_width="0dp"
                android:layout_height="match_parent"
                android:layout_weight="1"
                android:orientation="vertical"
                android:paddingBottom="@dimen/toolbar_padLeft"
                android:paddingTop="@dimen/toolbar_padLeft">

                <LinearLayout
                    android:layout_marginTop="12px"
                    android:layout_width="match_parent"
                    android:layout_height="66px"
                    android:layout_marginRight="@dimen/padding_top"
                    android:orientation="horizontal">

                    <RelativeLayout
                        android:id="@+id/item_shopcart_child_reduce"
                        android:layout_width="0dp"
                        android:layout_height="match_parent"
                        android:layout_weight="1"
                        android:background="@mipmap/shopping_cart_minus_bg">
                        <ImageView
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:layout_centerInParent="true"
                            android:src="@mipmap/shopping_cart_minus" />
                    </RelativeLayout>

                    <RelativeLayout
                        android:layout_width="0dp"
                        android:layout_height="match_parent"
                        android:layout_weight="1"
                        android:background="@mipmap/shopping_cart_num_bg">

                        <TextView
                            android:id="@+id/item_shopcart_child_goods_Num_edit"
                            style="@style/Shopcart_Good_CountEdit_Style"
                            android:layout_centerInParent="true"
                            android:text="3" />
                    </RelativeLayout>

                    <RelativeLayout
                        android:id="@+id/item_shopcart_child_add"
                        android:layout_width="0dp"
                        android:layout_height="match_parent"
                        android:layout_weight="1"
                        android:background="@mipmap/shopping_cart_add_bg">
                        <ImageView
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:layout_centerInParent="true"
                            android:src="@mipmap/shopping_cart_add" />
                    </RelativeLayout>
                </LinearLayout>

                <RelativeLayout
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:orientation="horizontal"
                    android:gravity="center_vertical">

                    <TextView
                        android:id="@+id/item_shopcart_child_goods_sizeEdit"
                        style="@style/Shopcart_Good_Size_Style"
                        android:layout_width="wrap_content"
                        android:text="规格：小猪  黄色" />

                    <ImageView
                        android:layout_toRightOf="@id/item_shopcart_child_goods_sizeEdit"
                        android:layout_alignBottom="@id/item_shopcart_child_goods_sizeEdit"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_marginLeft="@dimen/toolbar_padLeft"
                        android:src="@mipmap/shopping_cart_unfold" />
                </RelativeLayout>
            </LinearLayout>

            <TextView
                android:id="@+id/item_shopcart_child_del_goods"
                style="@style/Shopcart_Good_delete_Style" />
        </LinearLayout>
    </LinearLayout>
    <TextView
        android:id="@+id/item_shopcart_child_divideId"
        android:visibility="gone"
        android:layout_width="match_parent"
        android:layout_height="1px"
        android:background="@color/divide"
        android:layout_marginLeft="@dimen/toolbar_padLeft"
        android:layout_marginRight="@dimen/toolbar_padLeft"/>

</LinearLayout>

2.自定义适配器继承BaseExpandableListAdapter

一些点击操作由实现接口来处理。

package com.zxh.project.taobaoshoppingcart.adapter;

import android.content.Context;
import android.text.SpannableString;
import android.text.Spanned;
import android.text.style.StrikethroughSpan;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.CheckBox;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.TextView;

import com.zxh.project.taobaoshoppingcart.R;
import com.zxh.project.taobaoshoppingcart.customviews.CustomBaseDialog;
import com.zxh.project.taobaoshoppingcart.entity.ShoppingcartGoodsInfo;
import com.zxh.project.taobaoshoppingcart.entity.ShoppingcartStoreInfo;

import java.util.List;
import java.util.Map;

import butterknife.BindView;
import butterknife.ButterKnife;

/**
 * 购物车expandableListview适配器
 * @author ZhaoXH on 2017/8/11.
 */

public class ShoppingcartAdapter extends BaseExpandableListAdapter {
    private List<ShoppingcartStoreInfo> groups;
    //这个String对应着StoreInfo的Id，也就是店铺的Id
    private Map<String, List<ShoppingcartGoodsInfo>> childrens;
    private Context mcontext;
    private CheckInterface checkInterface;
    private ModifyCountInterface modifyCountInterface;
    private GroupEditorListener groupEditorListener;
    private int count = 0;
    private boolean flag=true; //组的编辑按钮是否可见，true可见，false不可见

    public ShoppingcartAdapter(List<ShoppingcartStoreInfo> groups, Map<String, List<ShoppingcartGoodsInfo>> childrens, Context mcontext) {
        this.groups = groups;
        this.childrens = childrens;
        this.mcontext = mcontext;
    }

    @Override
    public int getGroupCount() {
        return groups==null?0:groups.size();
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        String groupId = groups.get(groupPosition).getId();
        return childrens.get(groupId).size();
    }

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

    @Override
    public Object getChild(int groupPosition, int childPosition) {
        List<ShoppingcartGoodsInfo> childs = childrens.get(groups.get(groupPosition).getId());
        return childs.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) {
        final GroupViewHolder groupViewHolder;
        if (convertView == null) {
            convertView = View.inflate(mcontext, R.layout.item_shoppingcart_group, null);
            groupViewHolder = new GroupViewHolder(convertView);
            convertView.setTag(groupViewHolder);
        } else {
            groupViewHolder = (GroupViewHolder) convertView.getTag();
        }
        final ShoppingcartStoreInfo group = (ShoppingcartStoreInfo) getGroup(groupPosition);
        groupViewHolder.storeName.setText(group.getName());
        groupViewHolder.storeCheckBox.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                group.setChoosed(((CheckBox) v).isChecked());
                checkInterface.checkGroup(groupPosition, ((CheckBox) v).isChecked());
            }
        });
        groupViewHolder.storeCheckBox.setChecked(group.isChoosed());

        /**【文字指的是组的按钮的文字】
         * 当我们按下ActionBar的 "编辑"按钮， 应该把所有组的文字显示"编辑",并且设置按钮为不可见
         * 当我们完成编辑后，再把组的编辑按钮设置为可见
         * 不懂，请自己操作淘宝，观察一遍
         */
        if(group.isActionBarEditor()){
            group.setEditor(false);
            groupViewHolder.storeEdit.setVisibility(View.INVISIBLE);
            flag=false;
        }else{
            flag=true;
            groupViewHolder.storeEdit.setVisibility(View.VISIBLE);
        }

        /**
         * 思路:当我们按下组的"编辑"按钮后，组处于编辑状态，文字显示"完成"
         * 当我们点击“完成”按钮后，文字显示"编辑“,组处于未编辑状态
         */
        if (group.isEditor()) {
            groupViewHolder.storeEdit.setText("完成");
        } else {
            groupViewHolder.storeEdit.setText("编辑");
        }

        groupViewHolder.storeEdit.setOnClickListener(new GroupViewClick(group, groupPosition, groupViewHolder.storeEdit));
        return convertView;
    }

    @Override
    public View getChildView(final int groupPosition, final int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
        final ChildViewHolder childViewHolder;
        if (convertView == null) {
            convertView = View.inflate(mcontext, R.layout.item_shoppingcart_child, null);
            childViewHolder = new ChildViewHolder(convertView);
            convertView.setTag(childViewHolder);
        } else {
            childViewHolder = (ChildViewHolder) convertView.getTag();
        }

        /**
         * 根据组的编辑按钮的可见与不可见，去判断是组对下辖的子元素编辑  还是ActionBar对组的下瞎元素的编辑
         * 如果组的编辑按钮可见，那么肯定是组对自己下辖元素的编辑
         * 如果组的编辑按钮不可见，那么肯定是ActionBar对组下辖元素的编辑
         */
        if(flag){
            if (groups.get(groupPosition).isEditor()) {
                childViewHolder.editGoodsData.setVisibility(View.VISIBLE);
                childViewHolder.delGoods.setVisibility(View.VISIBLE);
                childViewHolder.goodsDataNoedit.setVisibility(View.GONE);
            } else {
                childViewHolder.delGoods.setVisibility(View.VISIBLE);
                childViewHolder.goodsDataNoedit.setVisibility(View.VISIBLE);
                childViewHolder.editGoodsData.setVisibility(View.GONE);
            }
        }else{

            if(groups.get(groupPosition).isActionBarEditor()){
                childViewHolder.delGoods.setVisibility(View.GONE);
                childViewHolder.editGoodsData.setVisibility(View.VISIBLE);
                childViewHolder.goodsDataNoedit.setVisibility(View.GONE);
            }else{
                childViewHolder.delGoods.setVisibility(View.VISIBLE);
                childViewHolder.goodsDataNoedit.setVisibility(View.VISIBLE);
                childViewHolder.editGoodsData.setVisibility(View.GONE);
            }
        }

        final ShoppingcartGoodsInfo child = (ShoppingcartGoodsInfo) getChild(groupPosition, childPosition);
        if (child != null) {
            childViewHolder.goodsName.setText(child.getDesc());
            childViewHolder.goodsPrice.setText("￥" + child.getPrice() + "");
            childViewHolder.goodsNumEdit.setText(String.valueOf(child.getCount()));
            childViewHolder.goodsImage.setImageResource(R.mipmap.goods_img);
            childViewHolder.goods_size.setText("类型:" + child.getColor() + ",颜色:" + child.getSize());
            childViewHolder.goodsSizeEdit.setText("类型:" + child.getColor() + ",颜色:" + child.getSize());
            //设置打折前的原价
            SpannableString spannableString = new SpannableString("￥" + child.getPrime_price() + "");
            StrikethroughSpan span = new StrikethroughSpan();
            spannableString.setSpan(span,0,spannableString.length()-1+1, Spanned.SPAN_INCLUSIVE_INCLUSIVE);
            //避免无限次的append
//            if (childViewHolder.goodsPrimePrice.length() > 0) {
//                childViewHolder.goodsPrimePrice.setText("");
//            }
//            childViewHolder.goodsPrimePrice.setText(spannableString);
            childViewHolder.goodsBuyNum.setText("x" + child.getCount() + "");
            childViewHolder.childCheckBox.setChecked(child.isChoosed());
            childViewHolder.childCheckBox.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    child.setChoosed(((CheckBox) v).isChecked());
                    childViewHolder.childCheckBox.setChecked(((CheckBox) v).isChecked());
                    checkInterface.checkChild(groupPosition, childPosition, ((CheckBox) v).isChecked());
                }
            });
            childViewHolder.increaseGoodsNum.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    modifyCountInterface.doIncrease(groupPosition, childPosition, childViewHolder.goodsNumEdit, childViewHolder.childCheckBox.isChecked());
                }
            });
            childViewHolder.reduceGoodsNum.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    modifyCountInterface.doDecrease(groupPosition, childPosition, childViewHolder.goodsNumEdit, childViewHolder.childCheckBox.isChecked());
                }
            });
            childViewHolder.goodsNumEdit.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
//                    showDialog(groupPosition,childPosition,childViewHolder.goodsNumEdit,childViewHolder.childCheckBox.isChecked(),child);
                }
            });
            childViewHolder.delGoods.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    final CustomBaseDialog dialog = new CustomBaseDialog(mcontext);
                    dialog.setContent("确定删除该商品吗?");
                    dialog.setCustomOnClickListener(new CustomBaseDialog.OnCustomDialogListener() {
                        @Override
                        public void setYesOnclick() {
                            modifyCountInterface.childDelete(groupPosition,childPosition);
                            dialog.dismiss();
                        }

                        @Override
                        public void setNoOnclick() {
                            dialog.dismiss();
                        }
                    });
                    dialog.show();
                }
            });
        }
        return convertView;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return false;
    }
    /**
     * 使某个小组处于编辑状态
     */
    private class GroupViewClick implements View.OnClickListener {
        private ShoppingcartStoreInfo group;
        private int groupPosition;
        private TextView editor;

        public GroupViewClick(ShoppingcartStoreInfo group, int groupPosition, TextView editor) {
            this.group = group;
            this.groupPosition = groupPosition;
            this.editor = editor;
        }

        @Override
        public void onClick(View v) {
            if (editor.getId() == v.getId()) {
                groupEditorListener.groupEditor(groupPosition);
                if (group.isEditor()) {
                    group.setEditor(false);
                } else {
                    group.setEditor(true);
                }
                notifyDataSetChanged();
            }
        }
    }

    /**
     * 店铺的复选框
     */
    public interface CheckInterface {
        /**
         * 组选框状态改变触发的事件
         *
         * @param groupPosition 组元素的位置
         * @param isChecked     组元素的选中与否
         */
        void checkGroup(int groupPosition, boolean isChecked);

        /**
         * 子选框状态改变触发的事件
         *
         * @param groupPosition 组元素的位置
         * @param childPosition 子元素的位置
         * @param isChecked     子元素的选中与否
         */
        void checkChild(int groupPosition, int childPosition, boolean isChecked);
    }

    /**
     * 改变数量的接口
     */
    public interface ModifyCountInterface {
        /**
         * 增加操作
         *
         * @param groupPosition 组元素的位置
         * @param childPosition 子元素的位置
         * @param showCountView 用于展示变化后数量的View
         * @param isChecked     子元素选中与否
         */
        void doIncrease(int groupPosition, int childPosition, View showCountView, boolean isChecked);

        void doDecrease(int groupPosition, int childPosition, View showCountView, boolean isChecked);

        void doUpdate(int groupPosition, int childPosition, View showCountView, boolean isChecked);

        /**
         * 删除子Item
         *
         * @param groupPosition
         * @param childPosition
         */
        void childDelete(int groupPosition, int childPosition);
    }



    public GroupEditorListener getGroupEditorListener() {
        return groupEditorListener;
    }

    public void setGroupEditorListener(GroupEditorListener groupEditorListener) {
        this.groupEditorListener = groupEditorListener;
    }

    public CheckInterface getCheckInterface() {
        return checkInterface;
    }

    public void setCheckInterface(CheckInterface checkInterface) {
        this.checkInterface = checkInterface;
    }

    public ModifyCountInterface getModifyCountInterface() {
        return modifyCountInterface;
    }

    public void setModifyCountInterface(ModifyCountInterface modifyCountInterface) {
        this.modifyCountInterface = modifyCountInterface;
    }
    /**
     * 监听编辑状态
     */
    public interface GroupEditorListener {
        void groupEditor(int groupPosition);
    }
    static class GroupViewHolder {
        @BindView(R.id.item_shopcart_group_checkBox)
        CheckBox storeCheckBox;
        @BindView(R.id.item_shopcart_group_nameTv)
        TextView storeName;
        @BindView(R.id.item_shopcart_group_editBtn)
        TextView storeEdit;

        public GroupViewHolder(View view) {
            ButterKnife.bind(this, view);
        }
    }
    static class ChildViewHolder {
        @BindView(R.id.item_shopcart_child_checkBox)
        CheckBox childCheckBox;
        @BindView(R.id.item_shopcart_child_goods_image)
        ImageView goodsImage;
        @BindView(R.id.item_shopcart_child_goods_name)
        TextView goodsName;
        @BindView(R.id.item_shopcart_child_goods_size)
        TextView goods_size;
        @BindView(R.id.item_shopcart_child_goods_price)
        TextView goodsPrice;
//        @BindView(R.id.goods_prime_price)
//        TextView goodsPrimePrice;
        @BindView(R.id.item_shopcart_child_goods_buyNum)
        TextView goodsBuyNum;
        @BindView(R.id.item_shopcart_child_goods_data_noedit)
        LinearLayout goodsDataNoedit;
        @BindView(R.id.item_shopcart_child_reduce)
        RelativeLayout reduceGoodsNum;
        @BindView(R.id.item_shopcart_child_goods_Num_edit)
        TextView goodsNumEdit;
        @BindView(R.id.item_shopcart_child_add)
        RelativeLayout increaseGoodsNum;
        @BindView(R.id.item_shopcart_child_goods_sizeEdit)
        TextView goodsSizeEdit;

        @BindView(R.id.item_shopcart_child_del_goods)
        TextView delGoods;
        @BindView(R.id.item_shopcart_child_edit_goods_data)
        LinearLayout editGoodsData;

        public ChildViewHolder(View view) {
            ButterKnife.bind(this, view);
        }
    }
}

3.重要的点击事件

右上角编辑按钮

    flag = !flag;//false就是右上角编辑，ture就是完成
    /**
     * ActionBar标题上点编辑的时候，只显示每一个店铺的商品修改界面
     * ActionBar标题上点完成的时候，只显示每一个店铺的商品信息界面
     */
    private void setActionBarEditor() {
        for (int i = 0; i < groups.size(); i++) {
            ShoppingcartStoreInfo group = groups.get(i);
            if (group.isActionBarEditor()) {
                group.setActionBarEditor(false);
            } else {
                group.setActionBarEditor(true);
            }
        }
        adapter.notifyDataSetChanged();
    }
    private void setVisiable() {
        if (flag) {
            orderInfo.setVisibility(View.GONE);
            shareInfo.setVisibility(View.VISIBLE);
            actionBarEdit.setText("完成");
        } else {
            orderInfo.setVisibility(View.VISIBLE);
            shareInfo.setVisibility(View.GONE);
            actionBarEdit.setText("编辑");
        }
    }

右上角为编辑状态下，删除按钮（选中删除）

/**
     * 删除操作
     * 1.不要边遍历边删除,容易出现数组越界的情况
     * 2.把将要删除的对象放进相应的容器中，待遍历完，用removeAll的方式进行删除
     */
    private void doDelete() {
        List<ShoppingcartStoreInfo> toBeDeleteGroups = new ArrayList<ShoppingcartStoreInfo>(); //待删除的组元素
        for (int i = 0; i < groups.size(); i++) {
            ShoppingcartStoreInfo group = groups.get(i);
            if (group.isChoosed()) {
                toBeDeleteGroups.add(group);
            }
            List<ShoppingcartGoodsInfo> toBeDeleteChilds = new ArrayList<ShoppingcartGoodsInfo>();//待删除的子元素
            List<ShoppingcartGoodsInfo> child = childs.get(group.getId());
            for (int j = 0; j < child.size(); j++) {
                if (child.get(j).isChoosed()) {
                    toBeDeleteChilds.add(child.get(j));
                }
            }
            child.removeAll(toBeDeleteChilds);
        }
        groups.removeAll(toBeDeleteGroups);
        //重新设置购物车
        setCartNum();
        adapter.notifyDataSetChanged();

    }

底部左下角的全选、反选按钮

 /**
     * 全选和反选
     * 错误标记：在这里出现过错误
     */
    private void doCheckAll() {
        for (int i = 0; i < groups.size(); i++) {
            ShoppingcartStoreInfo group = groups.get(i);
            group.setChoosed(allCheckBox.isChecked());
            List<ShoppingcartGoodsInfo> child = childs.get(group.getId());
            for (int j = 0; j < child.size(); j++) {
                child.get(j).setChoosed(allCheckBox.isChecked());//这里出现过错误
            }
        }
        adapter.notifyDataSetChanged();
        calulate();
    }

增加商品按钮

@Override
    public void doIncrease(int groupPosition, int childPosition, View showCountView, boolean isChecked) {
        ShoppingcartGoodsInfo good = (ShoppingcartGoodsInfo) adapter.getChild(groupPosition, childPosition);
        int count = good.getCount();
        count++;
        good.setCount(count);
        ((TextView) showCountView).setText(String.valueOf(count));
        adapter.notifyDataSetChanged();
        calulate();
    }

减少商品按钮

 /**
     * @param groupPosition
     * @param childPosition
     * @param showCountView
     * @param isChecked
     */
    @Override
    public void doDecrease(int groupPosition, int childPosition, View showCountView, boolean isChecked) {
        ShoppingcartGoodsInfo good = (ShoppingcartGoodsInfo) adapter.getChild(groupPosition, childPosition);
        int count = good.getCount();
        if (count == 1) {
            return;
        }
        count--;
        good.setCount(count);
        ((TextView) showCountView).setText("" + count);
        adapter.notifyDataSetChanged();
        calulate();
    }

组group选中按钮

/**
     * @param groupPosition 组元素的位置
     * @param isChecked     组元素的选中与否
     *                      思路:组元素被选中了，那么下辖全部的子元素也被选中
     */
    @Override
    public void checkGroup(int groupPosition, boolean isChecked) {
        ShoppingcartStoreInfo group = groups.get(groupPosition);
        List<ShoppingcartGoodsInfo> child = childs.get(group.getId());
        for (int i = 0; i < child.size(); i++) {
            child.get(i).setChoosed(isChecked);
        }
        if (isCheckAll()) {
            allCheckBox.setChecked(true);//全选
        } else {
            allCheckBox.setChecked(false);//反选
        }
        adapter.notifyDataSetChanged();
        calulate();
    }

子child选中按钮

 /**
     * @param groupPosition 组元素的位置
     * @param childPosition 子元素的位置
     * @param isChecked     子元素的选中与否
     */
    @Override
    public void checkChild(int groupPosition, int childPosition, boolean isChecked) {
        boolean allChildSameState = true; //判断该组下面的所有子元素是否处于同一状态
        ShoppingcartStoreInfo group = groups.get(groupPosition);
        List<ShoppingcartGoodsInfo> child = childs.get(group.getId());
        for (int i = 0; i < child.size(); i++) {
            //不选全中
            if (child.get(i).isChoosed() != isChecked) {
                allChildSameState = false;
                break;
            }
        }

        if (allChildSameState) {
            group.setChoosed(isChecked);//如果子元素状态相同，那么对应的组元素也设置成这一种的同一状态
        } else {
            group.setChoosed(false);//否则一律视为未选中
        }

        if (isCheckAll()) {
            allCheckBox.setChecked(true);//全选
        } else {
            allCheckBox.setChecked(false);//反选
        }

        adapter.notifyDataSetChanged();
        calulate();
    }

子child中删除按钮

/**
     * @param groupPosition
     * @param childPosition 思路:当子元素=0，那么组元素也要删除
     */
    @Override
    public void childDelete(int groupPosition, int childPosition) {
        ShoppingcartStoreInfo group = groups.get(groupPosition);
        List<ShoppingcartGoodsInfo> child = childs.get(group.getId());
        child.remove(childPosition);
        if (child.size() == 0) {
            groups.remove(groupPosition);
        }
        adapter.notifyDataSetChanged();
        calulate();
    }

计算商品价钱

/**
     * 计算商品总价格，操作步骤
     * 1.先清空全局计价,计数
     * 2.遍历所有的子元素，只要是被选中的，就进行相关的计算操作
     * 3.给textView填充数据
     */
    private void calulate() {
        mtotalPrice = 0.00;
        mtotalCount = 0;
        for (int i = 0; i < groups.size(); i++) {
            ShoppingcartStoreInfo group = groups.get(i);
            List<ShoppingcartGoodsInfo> child = childs.get(group.getId());
            for (int j = 0; j < child.size(); j++) {
                ShoppingcartGoodsInfo good = child.get(j);
                if (good.isChoosed()) {
                    mtotalCount++;
                    mtotalPrice += good.getPrice() * good.getCount();
                }
            }
        }
        totalPrice.setText("￥" + mtotalPrice + "");
        goPay.setText("结算(" + mtotalCount + ")");
        if (mtotalCount == 0) {
            setCartNum();
        } else {
            shoppingcatNum.setText("购物车(" + mtotalCount + ")");//类似淘宝标题栏的购物车数量
        }
    }

更新商品数量

@Override
    public void doUpdate(int groupPosition, int childPosition, View showCountView, boolean isChecked) {
        ShoppingcartGoodsInfo good = (ShoppingcartGoodsInfo) adapter.getChild(groupPosition, childPosition);
        int count = good.getCount();
        ((TextView) showCountView).setText(String.valueOf(count));
        adapter.notifyDataSetChanged();
        calulate();
    }

小结

购物车的逻辑还是比较复杂的，只要理清了其中的关系，代码写起来就简单多了。如果实在自己从头写不出来的话，就参考一下大神的代码。我就是参考大神的思路理清后才写出来的。欢迎大家查看。

需要的下载demo查看效果

购物车.png