Android购物车的实现（升级版 仿淘宝）
16lz
2021-01-23
前面有篇文章实现了Android 简单的购物车 这篇实现了购物车中商品按照店铺分类显示的 也就是淘宝购物车的显示方式。
主要代码
package com.jock.shopcart;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import android.app.Activity;import android.app.AlertDialog;import android.content.Context;import android.content.DialogInterface;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.view.Window;import android.widget.CheckBox;import android.widget.ExpandableListView;import android.widget.TextView;import android.widget.Toast;import com.jock.adapter.ShopcartExpandableListViewAdapter;import com.jock.adapter.ShopcartExpandableListViewAdapter.CheckInterface;import com.jock.adapter.ShopcartExpandableListViewAdapter.ModifyCountInterface;import com.jock.entity.GroupInfo;import com.jock.entity.ProductInfo;import com.jock.shopcar.R;public class MainActivity extends Activity implements CheckInterface, ModifyCountInterface, OnClickListener{private ExpandableListView exListView;private CheckBox cb_check_all;private TextView tv_total_price;private TextView tv_delete;private TextView tv_go_to_pay;private Context context;private double totalPrice = 0.00;// 购买的商品总价private int totalCount = 0;// 购买的商品总数量private ShopcartExpandableListViewAdapter selva;private List groups = new ArrayList();// 组元素数据列表private Map> children = new HashMap>();// 子元素数据列表@Overrideprotected void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);requestWindowFeature(Window.FEATURE_NO_TITLE);setContentView(R.layout.activity_main);initView();initEvents();}private void initView(){context = this;virtualData();exListView = (ExpandableListView) findViewById(R.id.exListView);cb_check_all = (CheckBox) findViewById(R.id.all_chekbox);tv_total_price = (TextView) findViewById(R.id.tv_total_price);tv_delete = (TextView) findViewById(R.id.tv_delete);tv_go_to_pay = (TextView) findViewById(R.id.tv_go_to_pay);}private void initEvents(){selva = new ShopcartExpandableListViewAdapter(groups, children, this);selva.setCheckInterface(this);// 关键步骤1,设置复选框接口selva.setModifyCountInterface(this);// 关键步骤2,设置数量增减接口exListView.setAdapter(selva);for (int i = 0; i < selva.getGroupCount(); i++){exListView.expandGroup(i);// 关键步骤3,初始化时，将ExpandableListView以展开的方式呈现}cb_check_all.setOnClickListener(this);tv_delete.setOnClickListener(this);tv_go_to_pay.setOnClickListener(this);}/** * 模拟数据
* 遵循适配器的数据列表填充原则，组元素被放在一个List中，对应的组元素下辖的子元素被放在Map中，
* 其键是组元素的Id(通常是一个唯一指定组元素身份的值) */private void virtualData(){for (int i = 0; i < 6; i++){groups.add(new GroupInfo(i + "", "第八号当铺" + (i + 1) + "号店"));List products = new ArrayList();for (int j = 0; j <= i; j++){products.add(new ProductInfo(j + "", "商品", "", groups.get(i).getName() + "的第" + (j + 1) + "个商品", 120.00 + i * j, 1));}children.put(groups.get(i).getId(), products);// 将组元素的一个唯一值，这里取Id，作为子元素List的Key}}@Overridepublic void onClick(View v){AlertDialog alert;switch (v.getId()){case R.id.all_chekbox:doCheckAll();break;case R.id.tv_go_to_pay:if (totalCount == 0){Toast.makeText(context, "请选择要支付的商品", Toast.LENGTH_LONG).show();return;}alert = new AlertDialog.Builder(context).create();alert.setTitle("操作提示");alert.setMessage("总计:\n" + totalCount + "种商品\n" + totalPrice + "元");alert.setButton(DialogInterface.BUTTON_NEGATIVE, "取消", new DialogInterface.OnClickListener(){@Overridepublic void onClick(DialogInterface dialog, int which){return;}});alert.setButton(DialogInterface.BUTTON_POSITIVE, "确定", new DialogInterface.OnClickListener(){@Overridepublic void onClick(DialogInterface dialog, int which){return;}});alert.show();break;case R.id.tv_delete:if (totalCount == 0){Toast.makeText(context, "请选择要移除的商品", Toast.LENGTH_LONG).show();return;}alert = new AlertDialog.Builder(context).create();alert.setTitle("操作提示");alert.setMessage("您确定要将这些商品从购物车中移除吗？");alert.setButton(DialogInterface.BUTTON_NEGATIVE, "取消", new DialogInterface.OnClickListener(){@Overridepublic void onClick(DialogInterface dialog, int which){return;}});alert.setButton(DialogInterface.BUTTON_POSITIVE, "确定", new DialogInterface.OnClickListener(){@Overridepublic void onClick(DialogInterface dialog, int which){doDelete();}});alert.show();break;}}/** * 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.现将要删除的对象放进相应的列表容器中，待遍历完后，以removeAll的方式进行删除 */protected void doDelete(){List toBeDeleteGroups = new ArrayList();// 待删除的组元素列表for (int i = 0; i < groups.size(); i++){GroupInfo group = groups.get(i);if (group.isChoosed()){toBeDeleteGroups.add(group);}List toBeDeleteProducts = new ArrayList();// 待删除的子元素列表List childs = children.get(group.getId());for (int j = 0; j < childs.size(); j++){if (childs.get(j).isChoosed()){toBeDeleteProducts.add(childs.get(j));}}childs.removeAll(toBeDeleteProducts);}groups.removeAll(toBeDeleteGroups);selva.notifyDataSetChanged();calculate();}@Overridepublic void doIncrease(int groupPosition, int childPosition, View showCountView, boolean isChecked){ProductInfo product = (ProductInfo) selva.getChild(groupPosition, childPosition);int currentCount = product.getCount();currentCount++;product.setCount(currentCount);((TextView) showCountView).setText(currentCount + "");selva.notifyDataSetChanged();calculate();}@Overridepublic void doDecrease(int groupPosition, int childPosition, View showCountView, boolean isChecked){ProductInfo product = (ProductInfo) selva.getChild(groupPosition, childPosition);int currentCount = product.getCount();if (currentCount == 1)return;currentCount--;product.setCount(currentCount);((TextView) showCountView).setText(currentCount + "");selva.notifyDataSetChanged();calculate();}@Overridepublic void checkGroup(int groupPosition, boolean isChecked){GroupInfo group = groups.get(groupPosition);List childs = children.get(group.getId());for (int i = 0; i < childs.size(); i++){childs.get(i).setChoosed(isChecked);}if (isAllCheck())cb_check_all.setChecked(true);elsecb_check_all.setChecked(false);selva.notifyDataSetChanged();calculate();}@Overridepublic void checkChild(int groupPosition, int childPosiTion, boolean isChecked){boolean allChildSameState = true;// 判断改组下面的所有子元素是否是同一种状态GroupInfo group = groups.get(groupPosition);List childs = children.get(group.getId());for (int i = 0; i < childs.size(); i++){if (childs.get(i).isChoosed() != isChecked){allChildSameState = false;break;}}if (allChildSameState){group.setChoosed(isChecked);// 如果所有子元素状态相同，那么对应的组元素被设为这种统一状态} else{group.setChoosed(false);// 否则，组元素一律设置为未选中状态}if (isAllCheck())cb_check_all.setChecked(true);elsecb_check_all.setChecked(false);selva.notifyDataSetChanged();calculate();}private boolean isAllCheck(){for (GroupInfo group : groups){if (!group.isChoosed())return false;}return true;}/** 全选与反选 */private void doCheckAll(){for (int i = 0; i < groups.size(); i++){groups.get(i).setChoosed(cb_check_all.isChecked());GroupInfo group = groups.get(i);List childs = children.get(group.getId());for (int j = 0; j < childs.size(); j++){childs.get(j).setChoosed(cb_check_all.isChecked());}}selva.notifyDataSetChanged();}/** * 统计操作
* 1.先清空全局计数器
* 2.遍历所有子元素，只要是被选中状态的，就进行相关的计算操作
* 3.给底部的textView进行数据填充 */private void calculate(){totalCount = 0;totalPrice = 0.00;for (int i = 0; i < groups.size(); i++){GroupInfo group = groups.get(i);List childs = children.get(group.getId());for (int j = 0; j < childs.size(); j++){ProductInfo product = childs.get(j);if (product.isChoosed()){totalCount++;totalPrice += product.getPrice() * product.getCount();}}}tv_total_price.setText("￥" + totalPrice);tv_go_to_pay.setText("去支付(" + totalCount + ")");}} 源码下载
修订版本源码下载
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