Android 开发笔记___实战项目：购物车

　　购物车的应用很广泛，电商app基本上都有它的身影。由于它用到了多种存储方式，通过项目对数据的存储有更高层次的了解。

1.设计思路

　　首先看看购物车的外观。第一次进入时里面是空的，去购物页面加入购物车以后，返回到购物车才能看到商品列表。

- - 商品图表
  - 名称
  - 数量
  - 单价
  - 总价

　　一般购物车图标出现在几乎所有的页面，或者某一个角落。

　　一旦有新的商品加入购物车，购物车图标上的商品数量就加一。

　　任何页面点击购物车图标直接进入购物车页面

　　用到的存储方式：

- 数据库SQLite：是最直观的数据库，购物车里的商品列表一定放在SQLite中，增删改查都少不了它。
- 共享参数sharedpreferences：不同页面上的购物车图标都有数字，表示商品数量。因为每个页面都要显示，如果用sqlite每次都要查询的话，就会很费资源。又因为商品数量需要持久存储，所以也不合适放在全局内存，不然下次启动就会清空。
- SD卡文件：通常电商app的图标都来自服务器端，又因为图片下载很耗流量，因此一次加载后面从SD卡中读取之前加载的内容，加载又快又不耗流量，一举两得。
- 全局内存：上面说了，访问SD卡果然是个好主意，然而商品频道、购物车频道等可能在一个页面显示多张商品小图，如果每张小图都访问依次SD卡，频繁的SD卡访问读写是很耗资源的。更好的办法是把商品小图加载进全局内存，这样直接从内存中获取图片，高效又快速。之所以不把商品大图放入全局内存，是因为大图很耗空间，一不小心就会占用几十兆内存。

2.小知识

　　菜单Menu

　　　　1. 选项菜单------optionMenu

　　　　　　　　通过按菜单键或点击事件触发

　　　　　　2.上下文菜单----contextMenu

　　　　　　　　通过长按事件触发

　　　　都有对应的菜单布局文件，放在res/menu目录下。

　　1.选项菜单------optionMenu

　　　　弹出选项菜单的途径有3种：

　　　　　　（1）按菜单键

　　　　　　（2）在代码中手动打开，即调用openOptionMenu方法

　　　　　　（3）按工具栏右侧的溢出菜单按钮

　　　 需要重写两种方法：

- onCreateOptionMenu：在页面打开时调用，需要指定菜单列表的XML文件。
- onOptionItemSelected：在列表的菜单项被选中时调用，需要对不同的菜单项做分支处理

 <menu xmlns:android="http://schemas.android.com/apk/res/android" >

     <item

         android:id="@+id/menu_change_time"

         android:orderInCategory="1"

         android:title="改变时间"/>

     <item

         android:id="@+id/menu_change_color"

         android:orderInCategory="8"

         android:title="改变颜色"/>

     <item

         android:id="@+id/menu_change_bg"

         android:orderInCategory="9"

         android:title="改变背景"/>

 </menu>

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

     android:layout_width="match_parent"

     android:layout_height="match_parent"

     android:focusable="true"

     android:focusableInTouchMode="true"

     android:orientation="vertical"

     android:padding="10dp" >

     <Button

         android:id="@+id/btn_option"

         android:layout_width="match_parent"

         android:layout_height="wrap_content"

         android:text="打开选项菜单，也可直接按菜单键"

         android:textColor="@color/black"

         android:textSize="17sp" />

     <TextView

         android:id="@+id/tv_option"

         android:layout_width="match_parent"

         android:layout_height="50dp"

         android:gravity="left|center"

         android:textColor="@color/black"

         android:textSize="17sp" />

 </LinearLayout>

 package com.example.alimjan.hello_world;

 /**

  * Created by alimjan on 7/13/2017.

  */

         import com.example.alimjan.hello_world.Utils.DateUtil;

         import android.app.Activity;

         import android.content.Context;

         import android.content.Intent;

         import android.graphics.Color;

         import android.os.Bundle;

         import android.support.v7.app.AppCompatActivity;

         import android.util.Log;

         import android.view.Menu;

         import android.view.MenuItem;

         import android.view.View;

         import android.view.View.OnClickListener;

         import android.widget.TextView;

 public class class_4_5_2_1 extends Activity implements OnClickListener {

     private static final String TAG = "MenuOptionActivity";

     private TextView tv_option;

     @Override

     protected void onCreate(Bundle savedInstanceState) {

         super.onCreate(savedInstanceState);

         setContentView(R.layout.code_4_5_2_1);

         tv_option = (TextView) findViewById(R.id.tv_option);

         findViewById(R.id.btn_option).setOnClickListener(this);

         setRandomTime();

     }

     @Override

     public void onClick(View v) {

         if (v.getId() == R.id.btn_option) {

             //注意：如果当前页面继承自AppCompatActivity，并且appcompat版本不低于22.1.0

             //那么调用openOptionsMenu方法将不会弹出菜单。这应该是Android的一个bug

             openOptionsMenu();

         }

     }

     @Override

     public boolean onCreateOptionsMenu(Menu menu) {

         getMenuInflater().inflate(R.menu.menu_option, menu);

         return true;

     }

     @Override

     public boolean onOptionsItemSelected(MenuItem item) {

         int id = item.getItemId();

         if (id == R.id.menu_change_time) {

             setRandomTime();

         } else if (id == R.id.menu_change_color) {

             tv_option.setTextColor(getRandomColor());

         } else if (id == R.id.menu_change_bg) {

             tv_option.setBackgroundColor(getRandomColor());

         }

         return true;

     }

     private void setRandomTime() {

         String desc = DateUtil.getCurDateStr("yyyy-MM-dd HH:mm:ss") + " 这里是菜单显示文本";

         tv_option.setText(desc);

     }

     private int[] mColorArray = {

             Color.BLACK, Color.WHITE, Color.RED, Color.YELLOW, Color.GREEN,

             Color.BLUE, Color.CYAN, Color.MAGENTA, Color.GRAY, Color.DKGRAY

     };

     private int getRandomColor() {

         int random = (int) (Math.random()*10 % 10);

         return mColorArray[random];

     }

     public static void startHome(Context mContext) {

         Intent intent = new Intent(mContext, class_4_5_2_1.class);

         mContext.startActivity(intent);

     }

 }

　　2.上下文菜单----ContextMenu

　　　　弹出上下文菜单的途径有两种：

　　　　　　（1）默认在某个控件长按时弹出。

　　　　　　　　　通常在onStart方法中加入registerForContextMenu方法为指定控件注册上下文菜单，在onStop函数中加入unregisterForContextMenu方法为指定控件注销上下文　　　　　　　　　　　　菜单

　　　　　　（2）在长按事件之外的其他时间中打开上下文菜单，先执行registerForContextMenu方法注册菜单，然后执行openContextMenu方法打开菜单，最后执行　　　　　　　　 unregisterForContextMenu方法注销菜单。

　　　　需要重写以下两种方法：

- onCreateContextMenu：在此指定菜单列表的XML文件，作为上下文菜单列表项的来源。
- onContextItemSelected：在此对不同的菜单项做分支处理。

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

     android:layout_width="match_parent"

     android:layout_height="match_parent"

     android:focusable="true"

     android:focusableInTouchMode="true"

     android:orientation="vertical"

     android:padding="10dp" >

     <Button

         android:id="@+id/btn_context"

         android:layout_width="match_parent"

         android:layout_height="wrap_content"

         android:text="打开上下文菜单，长按下面文本亦可"

         android:textColor="@color/black"

         android:textSize="17sp" />

     <TextView

         android:id="@+id/tv_context"

         android:layout_width="match_parent"

         android:layout_height="50dp"

         android:gravity="left|center"

         android:textColor="@color/black"

         android:textSize="17sp" />

 </LinearLayout>

 package com.example.alimjan.hello_world;

 /**

  * Created by alimjan on 7/13/2017.

  */

         import com.example.alimjan.hello_world.Utils.DateUtil;

         import android.content.Context;

         import android.content.Intent;

         import android.graphics.Color;

         import android.os.Bundle;

         import android.support.v7.app.AppCompatActivity;

         import android.view.ContextMenu;

         import android.view.ContextMenu.ContextMenuInfo;

         import android.view.View.OnClickListener;

         import android.view.MenuItem;

         import android.view.View;

         import android.view.Window;

         import android.widget.TextView;

 public class class_4_5_2_2 extends AppCompatActivity implements OnClickListener {

     private TextView tv_context;

     @Override

     protected void onCreate(Bundle savedInstanceState) {

         super.onCreate(savedInstanceState);

         setContentView(R.layout.code_4_5_2_2);

         tv_context = (TextView) findViewById(R.id.tv_context);

         findViewById(R.id.btn_context).setOnClickListener(this);

         setRandomTime();

     }

     @Override

     public void onClick(View v) {

         if (v.getId() == R.id.btn_context) {

             registerForContextMenu(v);

             openContextMenu(v);

             unregisterForContextMenu(v);

         }

     }

     @Override

     protected void onResume() {

         registerForContextMenu(tv_context);

         super.onResume();

     }

     @Override

     protected void onPause() {

         unregisterForContextMenu(tv_context);

         super.onPause();

     }

     @Override

     public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {

         getMenuInflater().inflate(R.menu.menu_option, menu);

     }

     @Override

     public boolean onContextItemSelected(MenuItem item) {

         int id = item.getItemId();

         if (id == R.id.menu_change_time) {

             setRandomTime();

         } else if (id == R.id.menu_change_color) {

             tv_context.setTextColor(getRandomColor());

         } else if (id == R.id.menu_change_bg) {

             tv_context.setBackgroundColor(getRandomColor());

         }

         return true;

     }

     private void setRandomTime() {

         String desc = DateUtil.getCurDateStr("yyyy-MM-dd HH:mm:ss") + " 这里是菜单显示文本";

         tv_context.setText(desc);

     }

     private int[] mColorArray = {

             Color.BLACK, Color.WHITE, Color.RED, Color.YELLOW, Color.GREEN,

             Color.BLUE, Color.CYAN, Color.MAGENTA, Color.GRAY, Color.DKGRAY

     };

     private int getRandomColor() {

         int random = (int) (Math.random()*10 % 10);

         return mColorArray[random];

     }

     public static void startHome(Context mContext) {

         Intent intent = new Intent(mContext, class_4_5_2_2.class);

         mContext.startActivity(intent);

     }

 }

上下文菜单的菜单列表固定显示在页面中部，菜单外的其他区域颜色会变深。

3.开始敲代码

　　步骤①　　想好代码文件与布局文件的名称。（这里因为放到自己的笔记本上，文件名按照序号来起。）

　　步骤②　　在AndroidManiFest.xml文件中补充相应的配置。

　　步骤③ 　　敲业务逻辑以及布局文件的代码。

　　下面贴代码：

shoppingcatractivity.java：

 package com.example.alimjan.hello_world;

 import android.app.Activity;

 import android.app.AlertDialog;

 import android.content.Context;

 import android.content.Intent;

 import android.graphics.Bitmap;

 import android.graphics.BitmapFactory;

 import android.graphics.Color;

 import android.os.Bundle;

 import android.os.Environment;

 import android.util.Log;

 import android.util.TypedValue;

 import android.view.ContextMenu;

 import android.view.ContextMenu.ContextMenuInfo;

 import android.view.Gravity;

 import android.view.Menu;

 import android.view.MenuItem;

 import android.view.View;

 import android.view.View.OnClickListener;

 import android.view.ViewGroup.LayoutParams;

 import android.view.Window;

 import android.widget.ImageView;

 import android.widget.ImageView.ScaleType;

 import android.widget.LinearLayout;

 import android.widget.TextView;

 import android.widget.Toast;

 import com.example.alimjan.hello_world.Utils.FileUtil;

 import com.example.alimjan.hello_world.bean.CartInfo;

 import com.example.alimjan.hello_world.bean.GoodsInfo;

 import com.example.alimjan.hello_world.dataBase.CartDBHelper;

 import com.example.alimjan.hello_world.dataBase.GoodsDBHelper;

 import com.example.alimjan.hello_world.Utils.DateUtil;

 import com.example.alimjan.hello_world.Utils.SharedUtil;

 import java.util.ArrayList;

 import java.util.HashMap;

 /**

  * Created by alimjan on 2017/07/13.

  */

 public class ShoppingCartActivity extends Activity implements OnClickListener {

     private final static String TAG = "ShoppingCartActivity";

     private ImageView iv_menu;

     private TextView tv_title;

     private TextView tv_count;

     private TextView tv_total_price;

     private LinearLayout ll_content;

     private LinearLayout ll_cart;

     private LinearLayout ll_empty;

     private int mCount;

     @Override

     protected void onCreate(Bundle savedInstanceState) {

         super.onCreate(savedInstanceState);

         requestWindowFeature(Window.FEATURE_NO_TITLE);

         setContentView(R.layout.activity_shopping_cart);

         iv_menu = (ImageView) findViewById(R.id.iv_menu);

         tv_title = (TextView) findViewById(R.id.tv_title);

         tv_count = (TextView) findViewById(R.id.tv_count);

         tv_total_price = (TextView) findViewById(R.id.tv_total_price);

         ll_content = (LinearLayout) findViewById(R.id.ll_content);

         ll_cart = (LinearLayout) findViewById(R.id.ll_cart);

         ll_empty = (LinearLayout) findViewById(R.id.ll_empty);

         iv_menu.setOnClickListener(this);

         findViewById(R.id.btn_shopping_channel).setOnClickListener(this);

         findViewById(R.id.btn_settle).setOnClickListener(this);

         iv_menu.setVisibility(View.VISIBLE);

         tv_title.setText("购物车");

     }

     //显示购物车图标中的商品数量

     private void showCount(int count) {

         mCount = count;

         tv_count.setText(""+mCount);

         if (mCount == 0) {

             ll_content.setVisibility(View.GONE);

             ll_cart.removeAllViews();

             ll_empty.setVisibility(View.VISIBLE);

         } else {

             ll_content.setVisibility(View.VISIBLE);

             ll_empty.setVisibility(View.GONE);

         }

     }

     @Override

     public void onClick(View v) {

         if (v.getId() == R.id.iv_menu) {

             openOptionsMenu();

         } else if (v.getId() == R.id.btn_shopping_channel) {

             Intent intent = new Intent(this, ShoppingChannelActivity.class);

             startActivity(intent);

         } else if (v.getId() == R.id.btn_settle) {

             AlertDialog.Builder builder = new AlertDialog.Builder(this);

             builder.setTitle("结算商品");

             builder.setMessage("客官抱歉，支付功能尚未开通，请下次再来");

             builder.setPositiveButton("我知道了", null);

             builder.create().show();

         }

     }

     @Override

     public boolean onCreateOptionsMenu(Menu menu) {

         getMenuInflater().inflate(R.menu.menu_cart, menu);

         return true;

     }

     @Override

     public boolean onOptionsItemSelected(MenuItem item) {

         int id = item.getItemId();

         if (id == R.id.menu_shopping) {

             Intent intent = new Intent(this, ShoppingChannelActivity.class);

             startActivity(intent);

         } else if (id == R.id.menu_clear) {

             //清空购物车数据库

             mCartHelper.deleteAll();

             ll_cart.removeAllViews();

             SharedUtil.getIntance(this).writeShared("count", "0");

             showCount(0);

             mCartGoods.clear();

             mGoodsMap.clear();

             Toast.makeText(this, "购物车已清空", Toast.LENGTH_SHORT).show();

         } else if (id == R.id.menu_return) {

             finish();

         }

         return true;

     }

     private HashMap<Integer, CartInfo> mCartGoods = new HashMap<Integer, CartInfo>();

     private View mContextView;

     @Override

     public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {

         mContextView = v;

         getMenuInflater().inflate(R.menu.menu_goods, menu);

     }

     @Override

     public boolean onContextItemSelected(MenuItem item) {

         CartInfo info = mCartGoods.get(mContextView.getId());

         int id = item.getItemId();

         if (id == R.id.menu_detail) {

             //跳转到查看商品详情页面

             goDetail(info.goods_id);

         } else if (id == R.id.menu_delete) {

             //从购物车删除商品的数据库操作

             long goods_id = info.goods_id;

             mCartHelper.delete("goods_id="+goods_id);

             ll_cart.removeView(mContextView);

             //更新购物车中的商品数量

             int left_count = mCount-info.count;

             for (int i=0; i<mCartArray.size(); i++) {

                 if (goods_id == mCartArray.get(i).goods_id) {

                     left_count = mCount-mCartArray.get(i).count;

                     mCartArray.remove(i);

                     break;

                 }

             }

             SharedUtil.getIntance(this).writeShared("count", ""+left_count);

             showCount(left_count);

             Toast.makeText(this, "已从购物车删除"+mGoodsMap.get(goods_id).name, Toast.LENGTH_SHORT).show();

             mGoodsMap.remove(goods_id);

             refreshTotalPrice();

         }

         return true;

     }

     private void goDetail(long rowid) {

         Intent intent = new Intent(this, ShoppingDetailActivity.class);

         intent.putExtra("goods_id", rowid);

         startActivity(intent);

     }

     private GoodsDBHelper mGoodsHelper;

     private CartDBHelper mCartHelper;

     private String mFirst = "true";

     @Override

     protected void onResume() {

         super.onResume();

         mCount = Integer.parseInt(SharedUtil.getIntance(this).readShared("count", "0"));

         showCount(mCount);

         mGoodsHelper = GoodsDBHelper.getInstance(this, 1);

         mGoodsHelper.openWriteLink();

         mCartHelper = CartDBHelper.getInstance(this, 1);

         mCartHelper.openWriteLink();

         mFirst = SharedUtil.getIntance(this).readShared("first", "true");

         downloadGoods();

         SharedUtil.getIntance(this).writeShared("first", "false");

         showCart();

     }

     @Override

     protected void onPause() {

         super.onPause();

         mGoodsHelper.closeLink();

         mCartHelper.closeLink();

     }

     private int mBeginViewId = 0x7F24FFF0;

     private ArrayList<CartInfo> mCartArray = new ArrayList<CartInfo>();

     private HashMap<Long, GoodsInfo> mGoodsMap = new HashMap<Long, GoodsInfo>();

     private void showCart() {

         mCartArray = mCartHelper.query("1=1");

         Log.d(TAG, "mCartArray.size()="+mCartArray.size());

         if (mCartArray==null || mCartArray.size()<=0) {

             return;

         }

         ll_cart.removeAllViews();

         LinearLayout ll_row = newLinearLayout(LinearLayout.HORIZONTAL, LayoutParams.WRAP_CONTENT);

         ll_row.addView(newTextView(0, 2, Gravity.CENTER, "图片", Color.BLACK, 15));

         ll_row.addView(newTextView(0, 3, Gravity.CENTER, "名称", Color.BLACK, 15));

         ll_row.addView(newTextView(0, 1, Gravity.CENTER, "数量", Color.BLACK, 15));

         ll_row.addView(newTextView(0, 1, Gravity.CENTER, "单价", Color.BLACK, 15));

         ll_row.addView(newTextView(0, 1, Gravity.CENTER, "总价", Color.BLACK, 15));

         ll_cart.addView(ll_row);

         for (int i=0; i<mCartArray.size(); i++) {

             final CartInfo info = mCartArray.get(i);

             GoodsInfo goods = mGoodsHelper.queryById(info.goods_id);

             Log.d(TAG, "name="+goods.name+",price="+goods.price+",desc="+goods.desc);

             mGoodsMap.put(info.goods_id, goods);

             ll_row = newLinearLayout(LinearLayout.HORIZONTAL, LayoutParams.WRAP_CONTENT);

             ll_row.setId(mBeginViewId+i);

             //添加商品小图

             ImageView iv_thumb = new ImageView(this);

             LinearLayout.LayoutParams iv_params = new LinearLayout.LayoutParams(

                     0, LayoutParams.WRAP_CONTENT, 2);

             iv_thumb.setLayoutParams(iv_params);

             iv_thumb.setScaleType(ScaleType.FIT_CENTER);

             iv_thumb.setImageBitmap(MainApplication.getInstance().mIconMap.get(info.goods_id));

             ll_row.addView(iv_thumb);

             //添加商品名称与描述

             LinearLayout ll_name = new LinearLayout(this);

             LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(

                     0, LayoutParams.MATCH_PARENT, 3);

             ll_name.setLayoutParams(params);

             ll_name.setOrientation(LinearLayout.VERTICAL);

             ll_name.addView(newTextView(-3, 1, Gravity.LEFT, goods.name, Color.BLACK, 17));

             ll_name.addView(newTextView(-3, 1, Gravity.LEFT, goods.desc, Color.GRAY, 12));

             ll_row.addView(ll_name);

             //添加商品数量、单价和总价

             ll_row.addView(newTextView(1, 1, Gravity.CENTER, ""+info.count, Color.BLACK, 17));

             ll_row.addView(newTextView(1, 1, Gravity.RIGHT, ""+(int)goods.price, Color.BLACK, 15));

             ll_row.addView(newTextView(1, 1, Gravity.RIGHT, ""+(int)(info.count*goods.price), Color.RED, 17));

             //给商品行添加点击事件

             ll_row.setOnClickListener(new OnClickListener() {

                 @Override

                 public void onClick(View v) {

                     goDetail(info.goods_id);

                 }

             });

             //给商品行注册上下文菜单

             unregisterForContextMenu(ll_row);

             registerForContextMenu(ll_row);

             mCartGoods.put(ll_row.getId(), info);

             ll_cart.addView(ll_row);

         }

         refreshTotalPrice();

     }

     private void refreshTotalPrice() {

         int total_price = 0;

         for (CartInfo info : mCartArray) {

             GoodsInfo goods = mGoodsMap.get(info.goods_id);

             total_price += goods.price*info.count;

         }

         tv_total_price.setText(""+total_price);

     }

     private LinearLayout newLinearLayout(int orientation, int height) {

         LinearLayout ll_new = new LinearLayout(this);

         LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(

                 LayoutParams.MATCH_PARENT, height);

         //params.setMargins(2, 2, 2, 2);

         ll_new.setLayoutParams(params);

         ll_new.setOrientation(orientation);

         ll_new.setBackgroundColor(Color.WHITE);

         return ll_new;

     }

     private TextView newTextView(int height, float weight, int gravity, String text, int textColor, int textSize) {

         TextView tv_new = new TextView(this);

         if (height == -3) {  //垂直排列

             LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(

                     LayoutParams.MATCH_PARENT, 0, weight);

             tv_new.setLayoutParams(params);

         } else {  //水平排列

             LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(

                     0, (height==0)?LayoutParams.WRAP_CONTENT:LayoutParams.MATCH_PARENT, weight);

             tv_new.setLayoutParams(params);

         }

         tv_new.setText(text);

         tv_new.setTextColor(textColor);

         tv_new.setTextSize(TypedValue.COMPLEX_UNIT_SP, textSize);

         tv_new.setGravity(Gravity.CENTER|gravity);

         return tv_new;

     }

     private String[] mNameArray = {

             "iphone7", "Mate8", "小米5", "vivo X6S", "OPPO R9plus", "魅族Pro6"

             };

     private String[] mDescArray = {

             "Apple iPhone 7 128GB 玫瑰金色 移动联通电信4G手机",

             "华为 HUAWEI Mate8 3GB+32GB版 移动联通4G手机（月光银）",

             "小米手机5 全网通 高配版 3GB内存 64GB 白色",

             "vivo X6S 金色 全网通4G 双卡双待 4GB+64GB",

             "OPPO R9plus 4GB+64GB内存版 金色 全网通4G手机 双卡双待",

             "魅族Pro6全网通公开版 4+32GB 银白色 移动联通电信4G手机 双卡双待"

             };

     private float[] mPriceArray = {5888, 2499, 1799, 2298, 2499, 2199};

     private int[] mThumbArray = {

             R.drawable.iphone_s, R.drawable.huawei_s, R.drawable.xiaomi_s,

             R.drawable.vivo_s, R.drawable.oppo_9p_s, R.drawable.meizu_s

             };

     private int[] mPicArray = {

             R.drawable.iphone, R.drawable.huawei, R.drawable.xiaomi,

             R.drawable.vivo, R.drawable.oppo_9p, R.drawable.meizu

             };

     //模拟网络数据，初始化数据库中的商品信息

     private void downloadGoods() {

         String path = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS) + "/";

         if (mFirst.equals("true")) {

             for (int i=0; i<mNameArray.length; i++) {

                 GoodsInfo info = new GoodsInfo();

                 info.name = mNameArray[i];

                 info.desc = mDescArray[i];

                 info.price = mPriceArray[i];

                 long rowid = mGoodsHelper.insert(info);

                 info.rowid = rowid;

                 //往全局内存写入商品小图

                 Bitmap thumb = BitmapFactory.decodeResource(getResources(), mThumbArray[i]);

                 MainApplication.getInstance().mIconMap.put(rowid, thumb);

                 String thumb_path = path + rowid + "_s.jpg";

                 FileUtil.saveImage(thumb_path, thumb);

                 info.thumb_path = thumb_path;

                 //往SD卡保存商品大图

                 Bitmap pic = BitmapFactory.decodeResource(getResources(), mPicArray[i]);

                 String pic_path = path + rowid + ".jpg";

                 FileUtil.saveImage(pic_path, pic);

                 pic.recycle();

                 info.pic_path = pic_path;

                 mGoodsHelper.update(info);

             }

         } else {

             ArrayList<GoodsInfo> goodsArray = mGoodsHelper.query("1=1");

             for (int i=0; i<goodsArray.size(); i++) {

                 GoodsInfo info = goodsArray.get(i);

                 Bitmap thumb = BitmapFactory.decodeFile(info.thumb_path);

                 MainApplication.getInstance().mIconMap.put(info.rowid, thumb);

             }

         }

     }

     public static void startHome(Context mContext) {

         Intent intent = new Intent(mContext, ShoppingCartActivity.class);

         mContext.startActivity(intent);

     }

 }

ShoppingChannelActivity:

 package com.example.alimjan.hello_world;

 import android.content.Intent;

 import android.graphics.Color;

 import android.os.Bundle;

 import android.support.v7.app.AppCompatActivity;

 import android.util.TypedValue;

 import android.view.Gravity;

 import android.view.View;

 import android.view.View.OnClickListener;

 import android.widget.Button;

 import android.widget.ImageView;

 import android.widget.ImageView.ScaleType;

 import android.widget.LinearLayout;

 import android.widget.LinearLayout.LayoutParams;

 import android.widget.TextView;

 import android.widget.Toast;

 import com.example.alimjan.hello_world.bean.CartInfo;

 import com.example.alimjan.hello_world.bean.GoodsInfo;

 import com.example.alimjan.hello_world.dataBase.CartDBHelper;

 import com.example.alimjan.hello_world.dataBase.GoodsDBHelper;

 import com.example.alimjan.hello_world.Utils.DateUtil;

 import com.example.alimjan.hello_world.Utils.SharedUtil;

 import java.util.ArrayList;

 /**

  * Created by alimjan on 2017/07/13.

  */

 public class ShoppingChannelActivity extends AppCompatActivity implements OnClickListener {

     private final static String TAG = "ShoppingChannelActivity";

     private TextView tv_title;

     private TextView tv_count;

     private LinearLayout ll_channel;

     private int mCount;

     @Override

     protected void onCreate(Bundle savedInstanceState) {

         super.onCreate(savedInstanceState);

         setContentView(R.layout.activity_shopping_channel);

         tv_title = (TextView) findViewById(R.id.tv_title);

         tv_count = (TextView) findViewById(R.id.tv_count);

         ll_channel = (LinearLayout) findViewById(R.id.ll_channel);

         findViewById(R.id.iv_cart).setOnClickListener(this);

         tv_title.setText("手机商场");

     }

     @Override

     public void onClick(View v) {

         if (v.getId() == R.id.iv_cart) {

             Intent intent = new Intent(this, ShoppingCartActivity.class);

             startActivity(intent);

         }

     }

     private void addToCart(long goods_id) {

         mCount++;

         tv_count.setText(""+mCount);

         SharedUtil.getIntance(this).writeShared("count", ""+mCount);

         CartInfo info = mCartHelper.queryByGoodsId(goods_id);

         if (info != null) {

             info.count++;

             info.update_time = DateUtil.getCurDateStr("");

             mCartHelper.update(info);

         } else {

             info = new CartInfo();

             info.goods_id = goods_id;

             info.count = 1;

             info.update_time = DateUtil.getCurDateStr("");

             mCartHelper.insert(info);

         }

     }

     private GoodsDBHelper mGoodsHelper;

     private CartDBHelper mCartHelper;

     @Override

     protected void onResume() {

         super.onResume();

         mCount = Integer.parseInt(SharedUtil.getIntance(this).readShared("count", "0"));

         tv_count.setText(""+mCount);

         mGoodsHelper = GoodsDBHelper.getInstance(this, 1);

         mGoodsHelper.openReadLink();

         mCartHelper = CartDBHelper.getInstance(this, 1);

         mCartHelper.openWriteLink();

         //展示商品列表

         showGoods();

     }

     @Override

     protected void onPause() {

         super.onPause();

         mGoodsHelper.closeLink();

         mCartHelper.closeLink();

     }

     private LayoutParams mFullParams, mHalfParams;

     private void showGoods() {

         ll_channel.removeAllViews();

         mFullParams = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);

         mHalfParams = new LayoutParams(0, LayoutParams.WRAP_CONTENT, 1);

         mHalfParams.setMargins(2, 2, 2, 2);

         LinearLayout ll_row = newLinearLayout(LinearLayout.HORIZONTAL, 0);

         ArrayList<GoodsInfo> goodsArray = mGoodsHelper.query("1=1");

         int i=0;

         for (; i<goodsArray.size(); i++) {

             final GoodsInfo info = goodsArray.get(i);

             LinearLayout ll_goods = newLinearLayout(LinearLayout.VERTICAL, 1);

             ll_goods.setBackgroundColor(Color.WHITE);

             //添加商品标题

             TextView tv_name = new TextView(this);

             tv_name.setLayoutParams(mFullParams);

             tv_name.setGravity(Gravity.CENTER);

             tv_name.setText(info.name);

             tv_name.setTextColor(Color.BLACK);

             tv_name.setTextSize(TypedValue.COMPLEX_UNIT_SP, 17);

             ll_goods.addView(tv_name);

             //添加商品小图

             ImageView iv_thumb = new ImageView(this);

             iv_thumb.setLayoutParams(new LayoutParams(

                     LayoutParams.MATCH_PARENT, 200));

             iv_thumb.setScaleType(ScaleType.FIT_CENTER);

             iv_thumb.setImageBitmap(MainApplication.getInstance().mIconMap.get(info.rowid));

             iv_thumb.setOnClickListener(new OnClickListener() {

                 @Override

                 public void onClick(View v) {

                     Intent intent = new Intent(ShoppingChannelActivity.this, ShoppingDetailActivity.class);

                     intent.putExtra("goods_id", info.rowid);

                     startActivity(intent);

                 }

             });

             ll_goods.addView(iv_thumb);

             //添加商品价格

             LinearLayout ll_bottom = newLinearLayout(LinearLayout.HORIZONTAL, 0);

             TextView tv_price = new TextView(this);

             tv_price.setLayoutParams(new LayoutParams(0, LayoutParams.WRAP_CONTENT, 2));

             tv_price.setGravity(Gravity.CENTER);

             tv_price.setText(""+(int)info.price);

             tv_price.setTextColor(Color.RED);

             tv_price.setTextSize(TypedValue.COMPLEX_UNIT_SP, 15);

             ll_bottom.addView(tv_price);

             //添加购物车按钮

             Button btn_add = new Button(this);

             btn_add.setLayoutParams(new LayoutParams(0, LayoutParams.WRAP_CONTENT, 3));

             btn_add.setGravity(Gravity.CENTER);

             btn_add.setText("加入购物车");

             btn_add.setTextColor(Color.BLACK);

             btn_add.setTextSize(TypedValue.COMPLEX_UNIT_SP, 15);

             btn_add.setOnClickListener(new OnClickListener() {

                 @Override

                 public void onClick(View v) {

                     addToCart(info.rowid);

                     Toast.makeText(ShoppingChannelActivity.this,

                             "已添加一部"+info.name+"到购物车", Toast.LENGTH_SHORT).show();

                 }

             });

             ll_bottom.addView(btn_add);

             ll_goods.addView(ll_bottom);

             //添加商品项目

             ll_row.addView(ll_goods);

             if (i%2 == 1) {

                 ll_channel.addView(ll_row);

                 ll_row = newLinearLayout(LinearLayout.HORIZONTAL, 0);

             }

         }

         if (i%2 == 0) {

             ll_row.addView(newLinearLayout(LinearLayout.VERTICAL, 1));

             ll_channel.addView(ll_row);

         }

     }

     private LinearLayout newLinearLayout(int orientation, int weight) {

         LinearLayout ll_new = new LinearLayout(this);

         ll_new.setLayoutParams((weight==0)?mFullParams:mHalfParams);

         ll_new.setOrientation(orientation);

         return ll_new;

     }

 }

ShoppingDetailActivity:

 package com.example.alimjan.hello_world;

 import android.content.Intent;

 import android.graphics.Bitmap;

 import android.graphics.BitmapFactory;

 import android.os.Bundle;

 import android.support.v7.app.AppCompatActivity;

 import android.view.View;

 import android.view.View.OnClickListener;

 import android.widget.ImageView;

 import android.widget.TextView;

 import android.widget.Toast;

 import com.example.alimjan.hello_world.bean.CartInfo;

 import com.example.alimjan.hello_world.bean.GoodsInfo;

 import com.example.alimjan.hello_world.dataBase.CartDBHelper;

 import com.example.alimjan.hello_world.dataBase.GoodsDBHelper;

 import com.example.alimjan.hello_world.Utils.DateUtil;

 import com.example.alimjan.hello_world.Utils.SharedUtil;

 /**

  * Created by alimjan on 2017/07/13.

  */

 public class ShoppingDetailActivity extends AppCompatActivity implements OnClickListener {

     private TextView tv_title;

     private TextView tv_count;

     private TextView tv_goods_price;

     private TextView tv_goods_desc;

     private ImageView iv_goods_pic;

     private int mCount;

     private long mGoodsId;

     @Override

     protected void onCreate(Bundle savedInstanceState) {

         super.onCreate(savedInstanceState);

         setContentView(R.layout.activity_shopping_detail);

         tv_title = (TextView) findViewById(R.id.tv_title);

         tv_count = (TextView) findViewById(R.id.tv_count);

         tv_goods_price = (TextView) findViewById(R.id.tv_goods_price);

         tv_goods_desc = (TextView) findViewById(R.id.tv_goods_desc);

         iv_goods_pic = (ImageView) findViewById(R.id.iv_goods_pic);

         findViewById(R.id.iv_cart).setOnClickListener(this);

         findViewById(R.id.btn_add_cart).setOnClickListener(this);

         mCount = Integer.parseInt(SharedUtil.getIntance(this).readShared("count", "0"));

         tv_count.setText(""+mCount);

     }

     @Override

     public void onClick(View v) {

         if (v.getId() == R.id.iv_cart) {

             Intent intent = new Intent(this, ShoppingCartActivity.class);

             startActivity(intent);

         } else if (v.getId() == R.id.btn_add_cart) {

             //添加购物车数据库

             addToCart(mGoodsId);

             Toast.makeText(this, "成功添加至购物车", Toast.LENGTH_SHORT).show();

         }

     }

     private void addToCart(long goods_id) {

         mCount++;

         tv_count.setText(""+mCount);

         SharedUtil.getIntance(this).writeShared("count", ""+mCount);

         CartInfo info = mCartHelper.queryByGoodsId(goods_id);

         if (info != null) {

             info.count++;

             info.update_time = DateUtil.getCurDateStr("");

             mCartHelper.update(info);

         } else {

             info = new CartInfo();

             info.goods_id = goods_id;

             info.count = 1;

             info.update_time = DateUtil.getCurDateStr("");

             mCartHelper.insert(info);

         }

     }

     private GoodsDBHelper mGoodsHelper;

     private CartDBHelper mCartHelper;

     @Override

     protected void onResume() {

         super.onResume();

         mGoodsHelper = GoodsDBHelper.getInstance(this, 1);

         mGoodsHelper.openReadLink();

         mCartHelper = CartDBHelper.getInstance(this, 1);

         mCartHelper.openWriteLink();

         //展示商品信息

         showDetail();

     }

     @Override

     protected void onPause() {

         super.onPause();

         mGoodsHelper.closeLink();

         mCartHelper.closeLink();

     }

     private void showDetail() {

         mGoodsId = getIntent().getLongExtra("goods_id", 0l);

         if (mGoodsId > 0) {

             GoodsInfo info = mGoodsHelper.queryById(mGoodsId);

             tv_title.setText(info.name);

             tv_goods_desc.setText(info.desc);

             tv_goods_price.setText(""+info.price);

             Bitmap pic = BitmapFactory.decodeFile(info.pic_path);

             iv_goods_pic.setImageBitmap(pic);

         }

     }

 }

activity_shopping_cart.xml

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

     android:layout_width="match_parent"

     android:layout_height="match_parent"

     android:background="#ffffdd"

     android:orientation="vertical" >

     <include layout="@layout/activity_shopping_title" />

     <ScrollView

         android:layout_width="match_parent"

         android:layout_height="wrap_content" >

         <FrameLayout

             android:layout_width="match_parent"

             android:layout_height="wrap_content"

             android:padding="5dp" >

             <LinearLayout

                 android:id="@+id/ll_content"

                 android:layout_width="match_parent"

                 android:layout_height="wrap_content"

                 android:orientation="vertical"

                 android:visibility="gone" >

                 <LinearLayout

                     android:id="@+id/ll_cart"

                     android:layout_width="match_parent"

                     android:layout_height="wrap_content"

                     android:orientation="vertical" >

                 </LinearLayout>

                 <LinearLayout

                     android:layout_width="match_parent"

                     android:layout_height="wrap_content"

                     android:orientation="horizontal"

                     android:padding="10dp" >

                     <TextView

                         android:layout_width="0dp"

                         android:layout_height="wrap_content"

                         android:layout_weight="1"

                         android:gravity="center|right"

                         android:text="总金额："

                         android:textColor="@color/black"

                         android:textSize="17sp" />

                     <TextView

                         android:id="@+id/tv_total_price"

                         android:layout_width="0dp"

                         android:layout_height="wrap_content"

                         android:layout_weight="2"

                         android:gravity="center|left"

                         android:textColor="@color/red"

                         android:textSize="25sp" />

                     <Button

                         android:id="@+id/btn_settle"

                         android:layout_width="0dp"

                         android:layout_height="wrap_content"

                         android:layout_weight="1"

                         android:gravity="center"

                         android:text="结算"

                         android:textColor="@color/black"

                         android:textSize="20sp" />

                 </LinearLayout>

             </LinearLayout>

             <LinearLayout

                 android:id="@+id/ll_empty"

                 android:layout_width="match_parent"

                 android:layout_height="wrap_content"

                 android:orientation="vertical"

                 android:visibility="gone" >

                 <TextView

                     android:layout_width="match_parent"

                     android:layout_height="wrap_content"

                     android:layout_marginBottom="100dp"

                     android:layout_marginTop="100dp"

                     android:gravity="center"

                     android:text="哎呀，购物车空空如也，快去选购商品吧"

                     android:textColor="@color/black"

                     android:textSize="17sp" />

                 <Button

                     android:id="@+id/btn_shopping_channel"

                     android:layout_width="match_parent"

                     android:layout_height="wrap_content"

                     android:gravity="center"

                     android:text="逛逛手机商场"

                     android:textColor="@color/black"

                     android:textSize="17sp" />

             </LinearLayout>

         </FrameLayout>

     </ScrollView>

 </LinearLayout>

activity_shopping_channel.xml

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

     android:layout_width="match_parent"

     android:layout_height="match_parent"

     android:background="#ffffdd"

     android:orientation="vertical" >

     <include layout="@layout/activity_shopping_title" />

     <ScrollView

         android:layout_width="match_parent"

         android:layout_height="wrap_content" >

         <LinearLayout

             android:id="@+id/ll_channel"

             android:layout_width="match_parent"

             android:layout_height="wrap_content"

             android:padding="5dp"

             android:orientation="vertical" >

         </LinearLayout>

     </ScrollView>

 </LinearLayout>

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

     android:layout_width="match_parent"

     android:layout_height="match_parent"

     android:background="#ffffdd"

     android:orientation="vertical" >

     <include layout="@layout/activity_shopping_title" />

     <ScrollView

         android:layout_width="match_parent"

         android:layout_height="wrap_content" >

         <LinearLayout

             android:layout_width="match_parent"

             android:layout_height="wrap_content"

             android:padding="5dp"

             android:orientation="vertical" >

             <ImageView

                 android:id="@+id/iv_goods_pic"

                 android:layout_width="match_parent"

                 android:layout_height="400dp"

                 android:scaleType="fitCenter" />

             <TextView

                 android:id="@+id/tv_goods_price"

                 android:layout_width="match_parent"

                 android:layout_height="wrap_content"

                 android:textColor="@color/red"

                 android:textSize="22sp" />

             <TextView

                 android:id="@+id/tv_goods_desc"

                 android:layout_width="match_parent"

                 android:layout_height="wrap_content"

                 android:textColor="@color/black"

                 android:textSize="15sp" />

             <Button

                 android:id="@+id/btn_add_cart"

                 android:layout_width="match_parent"

                 android:layout_height="wrap_content"

                 android:text="加入购物车"

                 android:textColor="@color/black"

                 android:textSize="17sp" />

         </LinearLayout>

     </ScrollView>

 </LinearLayout>

　　一些工具类：

 package com.example.alimjan.hello_world.Utils;

 import android.graphics.Bitmap;

 import android.graphics.BitmapFactory;

 import java.io.BufferedInputStream;

 import java.io.BufferedOutputStream;

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.FileOutputStream;

 import java.io.FilenameFilter;

 import java.util.ArrayList;

 import java.util.Locale;

 public class FileUtil {

     public static void saveText(String path, String txt) {

         try {

             FileOutputStream fos = new FileOutputStream(path);

             fos.write(txt.getBytes());

             fos.close();

         } catch (Exception e) {

             e.printStackTrace();

         }

     }

     public static String openText(String path) {

         String readStr = "";

         try {

             FileInputStream fis = new FileInputStream(path);

             byte[] b = new byte[fis.available()];

             fis.read(b);

             readStr = new String(b);

             fis.close();

         } catch (Exception e) {

             e.printStackTrace();

         }

         return readStr;

     }

     public static void saveImage(String path, Bitmap bitmap) {

         try {

             BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(path));

             bitmap.compress(Bitmap.CompressFormat.JPEG, 80, bos);

             bos.flush();

             bos.close();

         } catch (Exception e) {

             e.printStackTrace();

         }

     }

     public static Bitmap openImage(String path) {

         Bitmap bitmap = null;

         try {

             BufferedInputStream bis = new BufferedInputStream(new FileInputStream(path));

             bitmap = BitmapFactory.decodeStream(bis);

             bis.close();

         } catch (Exception e) {

             e.printStackTrace();

         }

         return bitmap;

     }

     public static ArrayList<File> getFileList(String path, String[] extendArray) {

         ArrayList<File> displayedContent = new ArrayList<File>();

         File[] files = null;

         File directory = new File(path);

         if (extendArray != null && extendArray.length>0) {

             FilenameFilter fileFilter = getTypeFilter(extendArray);

             files = directory.listFiles(fileFilter);

         } else {

             files = directory.listFiles();

         }

         if (files != null) {

             for (File f : files) {

                 if (!f.isDirectory() && !f.isHidden()) {

                     displayedContent.add(f);

                 }

             }

         }

         return displayedContent;

     }

     public static FilenameFilter getTypeFilter(String[] extendArray) {

         final ArrayList<String> fileExtensions = new ArrayList<String>();

         for (int i=0; i<extendArray.length; i++) {

             fileExtensions.add(extendArray[i]);

         }

         FilenameFilter fileNameFilter = new FilenameFilter() {

             @Override

             public boolean accept(File directory, String fileName) {

                 boolean matched = false;

                 File f = new File(String.format("%s/%s",

                         directory.getAbsolutePath(), fileName));

                 matched = f.isDirectory();

                 if (!matched) {

                     for (String s : fileExtensions) {

                         s = String.format(".{0,}\\%s$", s);

                         s = s.toUpperCase(Locale.getDefault());

                         fileName = fileName.toUpperCase(Locale.getDefault());

                         matched = fileName.matches(s);

                         if (matched) {

                             break;

                         }

                     }

                 }

                 return matched;

             }

         };

         return fileNameFilter;

     }

 }

 package com.example.alimjan.hello_world.dataBase;

 import android.content.ContentValues;

 import android.content.Context;

 import android.database.Cursor;

 import android.database.sqlite.SQLiteDatabase;

 import android.database.sqlite.SQLiteOpenHelper;

 import android.util.Log;

 import com.example.alimjan.hello_world.bean.GoodsInfo;

 import java.util.ArrayList;

 public class GoodsDBHelper extends SQLiteOpenHelper {

     private static final String TAG = "GoodsDBHelper";

     private static final String DB_NAME = "goods.db";

     private static final int DB_VERSION = 1;

     private static GoodsDBHelper mHelper = null;

     private SQLiteDatabase mDB = null;

     private static final String TABLE_NAME = "goods_info";

     private GoodsDBHelper(Context context) {

         super(context, DB_NAME, null, DB_VERSION);

     }

     private GoodsDBHelper(Context context, int version) {

         super(context, DB_NAME, null, version);

     }

     public static GoodsDBHelper getInstance(Context context, int version) {

         if (version > 0 && mHelper == null) {

             mHelper = new GoodsDBHelper(context, version);

         } else if (mHelper == null) {

             mHelper = new GoodsDBHelper(context);

         }

         return mHelper;

     }

     public SQLiteDatabase openReadLink() {

         if (mDB == null || mDB.isOpen() != true) {

             mDB = mHelper.getReadableDatabase();

         }

         return mDB;

     }

     public SQLiteDatabase openWriteLink() {

         if (mDB == null || mDB.isOpen() != true) {

             mDB = mHelper.getWritableDatabase();

         }

         return mDB;

     }

     public void closeLink() {

         if (mDB != null && mDB.isOpen() == true) {

             mDB.close();

             mDB = null;

         }

     }

     public String getDBName() {

         if (mHelper != null) {

             return mHelper.getDatabaseName();

         } else {

             return DB_NAME;

         }

     }

     @Override

     public void onCreate(SQLiteDatabase db) {

         Log.d(TAG, "onCreate");

         String drop_sql = "DROP TABLE IF EXISTS " + TABLE_NAME + ";";

         Log.d(TAG, "drop_sql:" + drop_sql);

         db.execSQL(drop_sql);

         String create_sql = "CREATE TABLE IF NOT EXISTS " + TABLE_NAME + " ("

                 + "_id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,"

                 + "name VARCHAR NOT NULL," + "desc VARCHAR NOT NULL,"

                 + "price FLOAT NOT NULL," + "thumb_path VARCHAR NOT NULL,"

                 + "pic_path VARCHAR NOT NULL"

                 + ");";

         Log.d(TAG, "create_sql:" + create_sql);

         db.execSQL(create_sql);

     }

     @Override

     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

     }

     public int delete(String condition) {

         int count = mDB.delete(TABLE_NAME, condition, null);

         return count;

     }

     public int deleteAll() {

         int count = mDB.delete(TABLE_NAME, "1=1", null);

         return count;

     }

     public long insert(GoodsInfo info) {

         ArrayList<GoodsInfo> infoArray = new ArrayList<GoodsInfo>();

         infoArray.add(info);

         return insert(infoArray);

     }

     public long insert(ArrayList<GoodsInfo> infoArray) {

         long result = -1;

         for (int i = 0; i < infoArray.size(); i++) {

             GoodsInfo info = infoArray.get(i);

             // 如果存在相同rowid的记录，则更新记录

             if (info.rowid > 0) {

                 String condition = String.format("rowid='%d'", info.rowid);

                 update(info, condition);

                 result = info.rowid;

                 continue;

             }

             // 不存在唯一性重复的记录，则插入新记录

             ContentValues cv = new ContentValues();

             cv.put("name", info.name);

             cv.put("desc", info.desc);

             cv.put("price", info.price);

             cv.put("thumb_path", info.thumb_path);

             cv.put("pic_path", info.pic_path);

             result = mDB.insert(TABLE_NAME, "", cv);

             // 添加成功后返回行号，失败后返回-1

             if (result == -1) {

                 return result;

             }

         }

         return result;

     }

     public int update(GoodsInfo info, String condition) {

         ContentValues cv = new ContentValues();

         cv.put("name", info.name);

         cv.put("desc", info.desc);

         cv.put("price", info.price);

         cv.put("thumb_path", info.thumb_path);

         cv.put("pic_path", info.pic_path);

         int count = mDB.update(TABLE_NAME, cv, condition, null);

         return count;

     }

     public int update(GoodsInfo info) {

         return update(info, "rowid="+info.rowid);

     }

     public ArrayList<GoodsInfo> query(String condition) {

         String sql = String.format("select rowid,_id,name,desc,price,thumb_path,pic_path" +

                 " from %s where %s;", TABLE_NAME, condition);

         Log.d(TAG, "query sql: "+sql);

         ArrayList<GoodsInfo> infoArray = new ArrayList<GoodsInfo>();

         Cursor cursor = mDB.rawQuery(sql, null);

         if (cursor.moveToFirst()) {

             for (;; cursor.moveToNext()) {

                 GoodsInfo info = new GoodsInfo();

                 info.rowid = cursor.getLong(0);

                 info.xuhao = cursor.getInt(1);

                 info.name = cursor.getString(2);

                 info.desc = cursor.getString(3);

                 info.price = cursor.getFloat(4);

                 info.thumb_path = cursor.getString(5);

                 info.pic_path = cursor.getString(6);

                 infoArray.add(info);

                 if (cursor.isLast() == true) {

                     break;

                 }

             }

         }

         cursor.close();

         return infoArray;

     }

     public GoodsInfo queryById(long rowid) {

         GoodsInfo info = null;

         ArrayList<GoodsInfo> infoArray = query(String.format("rowid='%d'", rowid));

         if (infoArray.size() > 0) {

             info = infoArray.get(0);

         }

         return info;

     }

 }

 package com.example.alimjan.hello_world.dataBase;

 import android.content.ContentValues;

 import android.content.Context;

 import android.database.Cursor;

 import android.database.sqlite.SQLiteDatabase;

 import android.database.sqlite.SQLiteOpenHelper;

 import android.util.Log;

 import com.example.alimjan.hello_world.bean.CartInfo;

 import java.util.ArrayList;

 public class CartDBHelper extends SQLiteOpenHelper {

     private static final String TAG = "CartDBHelper";

     private static final String DB_NAME = "cart.db";

     private static final int DB_VERSION = 1;

     private static CartDBHelper mHelper = null;

     private SQLiteDatabase mDB = null;

     private static final String TABLE_NAME = "cart_info";

     private CartDBHelper(Context context) {

         super(context, DB_NAME, null, DB_VERSION);

     }

     private CartDBHelper(Context context, int version) {

         super(context, DB_NAME, null, version);

     }

     public static CartDBHelper getInstance(Context context, int version) {

         if (version > 0 && mHelper == null) {

             mHelper = new CartDBHelper(context, version);

         } else if (mHelper == null) {

             mHelper = new CartDBHelper(context);

         }

         return mHelper;

     }

     public SQLiteDatabase openReadLink() {

         if (mDB == null || mDB.isOpen() != true) {

             mDB = mHelper.getReadableDatabase();

         }

         return mDB;

     }

     public SQLiteDatabase openWriteLink() {

         if (mDB == null || mDB.isOpen() != true) {

             mDB = mHelper.getWritableDatabase();

         }

         return mDB;

     }

     public void closeLink() {

         if (mDB != null && mDB.isOpen() == true) {

             mDB.close();

             mDB = null;

         }

     }

     public String getDBName() {

         if (mHelper != null) {

             return mHelper.getDatabaseName();

         } else {

             return DB_NAME;

         }

     }

     @Override

     public void onCreate(SQLiteDatabase db) {

         Log.d(TAG, "onCreate");

         String drop_sql = "DROP TABLE IF EXISTS " + TABLE_NAME + ";";

         Log.d(TAG, "drop_sql:" + drop_sql);

         db.execSQL(drop_sql);

         String create_sql = "CREATE TABLE IF NOT EXISTS " + TABLE_NAME + " ("

                 + "_id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,"

                 + "goods_id LONG NOT NULL," + "count INTEGER NOT NULL,"

                 + "update_time VARCHAR NOT NULL"

                 + ");";

         Log.d(TAG, "create_sql:" + create_sql);

         db.execSQL(create_sql);

     }

     @Override

     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

     }

     public int delete(String condition) {

         int count = mDB.delete(TABLE_NAME, condition, null);

         return count;

     }

     public int deleteAll() {

         int count = mDB.delete(TABLE_NAME, "1=1", null);

         return count;

     }

     public long insert(CartInfo info) {

         ArrayList<CartInfo> infoArray = new ArrayList<CartInfo>();

         infoArray.add(info);

         return insert(infoArray);

     }

     public long insert(ArrayList<CartInfo> infoArray) {

         long result = -1;

         for (int i = 0; i < infoArray.size(); i++) {

             CartInfo info = infoArray.get(i);

             Log.d(TAG, "goods_id="+info.goods_id+", count="+info.count);

             // 如果存在相同rowid的记录，则更新记录

             if (info.rowid > 0) {

                 String condition = String.format("rowid='%d'", info.rowid);

                 update(info, condition);

                 result = info.rowid;

                 continue;

             }

             // 不存在唯一性重复的记录，则插入新记录

             ContentValues cv = new ContentValues();

             cv.put("goods_id", info.goods_id);

             cv.put("count", info.count);

             cv.put("update_time", info.update_time);

             result = mDB.insert(TABLE_NAME, "", cv);

             // 添加成功后返回行号，失败后返回-1

             if (result == -1) {

                 return result;

             }

         }

         return result;

     }

     public int update(CartInfo info, String condition) {

         ContentValues cv = new ContentValues();

         cv.put("goods_id", info.goods_id);

         cv.put("count", info.count);

         cv.put("update_time", info.update_time);

         int count = mDB.update(TABLE_NAME, cv, condition, null);

         return count;

     }

     public int update(CartInfo info) {

         return update(info, "rowid="+info.rowid);

     }

     public ArrayList<CartInfo> query(String condition) {

         String sql = String.format("select rowid,_id,goods_id,count,update_time" +

                 " from %s where %s;", TABLE_NAME, condition);

         Log.d(TAG, "query sql: "+sql);

         ArrayList<CartInfo> infoArray = new ArrayList<CartInfo>();

         Cursor cursor = mDB.rawQuery(sql, null);

         if (cursor.moveToFirst()) {

             for (;; cursor.moveToNext()) {

                 CartInfo info = new CartInfo();

                 info.rowid = cursor.getLong(0);

                 info.xuhao = cursor.getInt(1);

                 info.goods_id = cursor.getLong(2);

                 info.count = cursor.getInt(3);

                 info.update_time = cursor.getString(4);

                 infoArray.add(info);

                 if (cursor.isLast() == true) {

                     break;

                 }

             }

         }

         cursor.close();

         return infoArray;

     }

     public CartInfo queryById(long rowid) {

         CartInfo info = null;

         ArrayList<CartInfo> infoArray = query(String.format("rowid='%d'", rowid));

         if (infoArray.size() > 0) {

             info = infoArray.get(0);

         }

         return info;

     }

     public CartInfo queryByGoodsId(long goods_id) {

         CartInfo info = null;

         ArrayList<CartInfo> infoArray = query(String.format("goods_id='%d'", goods_id));

         if (infoArray.size() > 0) {

             info = infoArray.get(0);

         }

         return info;

     }

 }

 package com.example.alimjan.hello_world.bean;

 public class GoodsInfo {

     public long rowid;

     public int xuhao;

     public String name;

     public String desc;

     public float price;

     public String thumb_path;

     public String pic_path;

     public GoodsInfo() {

         rowid = 0l;

         xuhao = 0;

         name = "";

         desc = "";

         price = 0;

         thumb_path = "";

         pic_path = "";

     }

 }

 package com.example.alimjan.hello_world.bean;

 public class CartInfo {

     public long rowid;

     public int xuhao;

     public long goods_id;

     public int count;

     public String update_time;

     public CartInfo() {

         rowid = 0l;

         xuhao = 0;

         goods_id = 0l;

         count = 0;

         update_time = "";

     }

 }

<menu xmlns:android="http://schemas.android.com/apk/res/android" >

    <item

        android:id="@+id/menu_shopping"

        android:orderInCategory="1"

        android:title="去商场购物"/>

    <item

        android:id="@+id/menu_clear"

        android:orderInCategory="2"

        android:title="清空购物车"/>

    <item

        android:id="@+id/menu_return"

        android:orderInCategory="9"

        android:title="返回"/>

</menu>

<menu xmlns:android="http://schemas.android.com/apk/res/android" >

    <item

        android:id="@+id/menu_detail"

        android:orderInCategory="1"

        android:title="查看商品详情"/>

    <item

        android:id="@+id/menu_delete"

        android:orderInCategory="2"

        android:title="从购物车删除"/>

</menu>

<?xml version="1.0" encoding="utf-8"?>

<shape xmlns:android="http://schemas.android.com/apk/res/android"

    android:shape="oval" >

    <solid android:color="#ff6666" />

</shape>

到此也就完成的差不多了，一些工具类放在下面了。

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