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
      1.  <menu xmlns:android="http://schemas.android.com/apk/res/android" >
      2.  
      3.      <item
      4.          android:id="@+id/menu_change_time"
      5.          android:orderInCategory="1"
      6.          android:title="改变时间"/>
      7.  
      8.      <item
      9.          android:id="@+id/menu_change_color"
      10.          android:orderInCategory="8"
      11.          android:title="改变颜色"/>
      12.  
      13.      <item
      14.          android:id="@+id/menu_change_bg"
      15.          android:orderInCategory="9"
      16.          android:title="改变背景"/>
      17.  
      18.  </menu>

      1.  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      2.      android:layout_width="match_parent"
      3.      android:layout_height="match_parent"
      4.      android:focusable="true"
      5.      android:focusableInTouchMode="true"
      6.      android:orientation="vertical"
      7.      android:padding="10dp" >
      8.  
      9.      <Button
      10.          android:id="@+id/btn_option"
      11.          android:layout_width="match_parent"
      12.          android:layout_height="wrap_content"
      13.          android:text="打开选项菜单，也可直接按菜单键"
      14.          android:textColor="@color/black"
      15.          android:textSize="17sp" />
      16.  
      17.      <TextView
      18.          android:id="@+id/tv_option"
      19.          android:layout_width="match_parent"
      20.          android:layout_height="50dp"
      21.          android:gravity="left|center"
      22.          android:textColor="@color/black"
      23.          android:textSize="17sp" />
      24.  
      25.  </LinearLayout>
      1.  package com.example.alimjan.hello_world;
      2.  
      3.  /**
      4.   * Created by alimjan on 7/13/2017.
      5.   */
      6.  
      7.          import com.example.alimjan.hello_world.Utils.DateUtil;
      8.          import android.app.Activity;
      9.          import android.content.Context;
      10.          import android.content.Intent;
      11.          import android.graphics.Color;
      12.          import android.os.Bundle;
      13.          import android.support.v7.app.AppCompatActivity;
      14.          import android.util.Log;
      15.          import android.view.Menu;
      16.          import android.view.MenuItem;
      17.          import android.view.View;
      18.          import android.view.View.OnClickListener;
      19.          import android.widget.TextView;
      20.  
      21.  public class class_4_5_2_1 extends Activity implements OnClickListener {
      22.  
      23.      private static final String TAG = "MenuOptionActivity";
      24.      private TextView tv_option;
      25.  
      26.      @Override
      27.      protected void onCreate(Bundle savedInstanceState) {
      28.          super.onCreate(savedInstanceState);
      29.          setContentView(R.layout.code_4_5_2_1);
      30.          tv_option = (TextView) findViewById(R.id.tv_option);
      31.          findViewById(R.id.btn_option).setOnClickListener(this);
      32.  
      33.          setRandomTime();
      34.      }
      35.  
      36.      @Override
      37.      public void onClick(View v) {
      38.          if (v.getId() == R.id.btn_option) {
      39.              //注意：如果当前页面继承自AppCompatActivity，并且appcompat版本不低于22.1.0
      40.              //那么调用openOptionsMenu方法将不会弹出菜单。这应该是Android的一个bug
      41.              openOptionsMenu();
      42.          }
      43.      }
      44.  
      45.      @Override
      46.      public boolean onCreateOptionsMenu(Menu menu) {
      47.          getMenuInflater().inflate(R.menu.menu_option, menu);
      48.          return true;
      49.      }
      50.  
      51.      @Override
      52.      public boolean onOptionsItemSelected(MenuItem item) {
      53.          int id = item.getItemId();
      54.          if (id == R.id.menu_change_time) {
      55.              setRandomTime();
      56.          } else if (id == R.id.menu_change_color) {
      57.              tv_option.setTextColor(getRandomColor());
      58.          } else if (id == R.id.menu_change_bg) {
      59.              tv_option.setBackgroundColor(getRandomColor());
      60.          }
      61.          return true;
      62.      }
      63.  
      64.      private void setRandomTime() {
      65.          String desc = DateUtil.getCurDateStr("yyyy-MM-dd HH:mm:ss") + " 这里是菜单显示文本";
      66.          tv_option.setText(desc);
      67.      }
      68.  
      69.      private int[] mColorArray = {
      70.              Color.BLACK, Color.WHITE, Color.RED, Color.YELLOW, Color.GREEN,
      71.              Color.BLUE, Color.CYAN, Color.MAGENTA, Color.GRAY, Color.DKGRAY
      72.      };
      73.      private int getRandomColor() {
      74.          int random = (int) (Math.random()*10 % 10);
      75.          return mColorArray[random];
      76.      }
      77.      public static void startHome(Context mContext) {
      78.          Intent intent = new Intent(mContext, class_4_5_2_1.class);
      79.          mContext.startActivity(intent);
      80.      }
      81.  
      82.  }

　　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。
      1.  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      2.      android:layout_width="match_parent"
      3.      android:layout_height="match_parent"
      4.      android:focusable="true"
      5.      android:focusableInTouchMode="true"
      6.      android:orientation="vertical"
      7.      android:padding="10dp" >
      8.  
      9.      <Button
      10.          android:id="@+id/btn_context"
      11.          android:layout_width="match_parent"
      12.          android:layout_height="wrap_content"
      13.          android:text="打开上下文菜单，长按下面文本亦可"
      14.          android:textColor="@color/black"
      15.          android:textSize="17sp" />
      16.  
      17.      <TextView
      18.          android:id="@+id/tv_context"
      19.          android:layout_width="match_parent"
      20.          android:layout_height="50dp"
      21.          android:gravity="left|center"
      22.          android:textColor="@color/black"
      23.          android:textSize="17sp" />
      24.  
      25.  </LinearLayout>
      1.  package com.example.alimjan.hello_world;
      2.  
      3.  /**
      4.   * Created by alimjan on 7/13/2017.
      5.   */
      6.          import com.example.alimjan.hello_world.Utils.DateUtil;
      7.  
      8.          import android.content.Context;
      9.          import android.content.Intent;
      10.          import android.graphics.Color;
      11.          import android.os.Bundle;
      12.          import android.support.v7.app.AppCompatActivity;
      13.          import android.view.ContextMenu;
      14.          import android.view.ContextMenu.ContextMenuInfo;
      15.          import android.view.View.OnClickListener;
      16.          import android.view.MenuItem;
      17.          import android.view.View;
      18.          import android.view.Window;
      19.          import android.widget.TextView;
      20.  
      21.  public class class_4_5_2_2 extends AppCompatActivity implements OnClickListener {
      22.  
      23.      private TextView tv_context;
      24.  
      25.      @Override
      26.      protected void onCreate(Bundle savedInstanceState) {
      27.          super.onCreate(savedInstanceState);
      28.          setContentView(R.layout.code_4_5_2_2);
      29.          tv_context = (TextView) findViewById(R.id.tv_context);
      30.          findViewById(R.id.btn_context).setOnClickListener(this);
      31.  
      32.          setRandomTime();
      33.      }
      34.  
      35.      @Override
      36.      public void onClick(View v) {
      37.          if (v.getId() == R.id.btn_context) {
      38.              registerForContextMenu(v);
      39.              openContextMenu(v);
      40.              unregisterForContextMenu(v);
      41.          }
      42.      }
      43.  
      44.      @Override
      45.      protected void onResume() {
      46.          registerForContextMenu(tv_context);
      47.          super.onResume();
      48.      }
      49.  
      50.      @Override
      51.      protected void onPause() {
      52.          unregisterForContextMenu(tv_context);
      53.          super.onPause();
      54.      }
      55.  
      56.      @Override
      57.      public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
      58.          getMenuInflater().inflate(R.menu.menu_option, menu);
      59.      }
      60.  
      61.      @Override
      62.      public boolean onContextItemSelected(MenuItem item) {
      63.          int id = item.getItemId();
      64.          if (id == R.id.menu_change_time) {
      65.              setRandomTime();
      66.          } else if (id == R.id.menu_change_color) {
      67.              tv_context.setTextColor(getRandomColor());
      68.          } else if (id == R.id.menu_change_bg) {
      69.              tv_context.setBackgroundColor(getRandomColor());
      70.          }
      71.          return true;
      72.      }
      73.  
      74.      private void setRandomTime() {
      75.          String desc = DateUtil.getCurDateStr("yyyy-MM-dd HH:mm:ss") + " 这里是菜单显示文本";
      76.          tv_context.setText(desc);
      77.      }
      78.  
      79.      private int[] mColorArray = {
      80.              Color.BLACK, Color.WHITE, Color.RED, Color.YELLOW, Color.GREEN,
      81.              Color.BLUE, Color.CYAN, Color.MAGENTA, Color.GRAY, Color.DKGRAY
      82.      };
      83.      private int getRandomColor() {
      84.          int random = (int) (Math.random()*10 % 10);
      85.          return mColorArray[random];
      86.      }
      87.      public static void startHome(Context mContext) {
      88.          Intent intent = new Intent(mContext, class_4_5_2_2.class);
      89.          mContext.startActivity(intent);
      90.      }
      91.  
      92.  }

      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：

  1.  package com.example.alimjan.hello_world;
  2.  
  3.  import android.app.Activity;
  4.  import android.app.AlertDialog;
  5.  import android.content.Context;
  6.  import android.content.Intent;
  7.  import android.graphics.Bitmap;
  8.  import android.graphics.BitmapFactory;
  9.  import android.graphics.Color;
  10.  import android.os.Bundle;
  11.  import android.os.Environment;
  12.  import android.util.Log;
  13.  import android.util.TypedValue;
  14.  import android.view.ContextMenu;
  15.  import android.view.ContextMenu.ContextMenuInfo;
  16.  import android.view.Gravity;
  17.  import android.view.Menu;
  18.  import android.view.MenuItem;
  19.  import android.view.View;
  20.  import android.view.View.OnClickListener;
  21.  import android.view.ViewGroup.LayoutParams;
  22.  import android.view.Window;
  23.  import android.widget.ImageView;
  24.  import android.widget.ImageView.ScaleType;
  25.  import android.widget.LinearLayout;
  26.  import android.widget.TextView;
  27.  import android.widget.Toast;
  28.  
  29.  import com.example.alimjan.hello_world.Utils.FileUtil;
  30.  import com.example.alimjan.hello_world.bean.CartInfo;
  31.  import com.example.alimjan.hello_world.bean.GoodsInfo;
  32.  import com.example.alimjan.hello_world.dataBase.CartDBHelper;
  33.  import com.example.alimjan.hello_world.dataBase.GoodsDBHelper;
  34.  import com.example.alimjan.hello_world.Utils.DateUtil;
  35.  import com.example.alimjan.hello_world.Utils.SharedUtil;
  36.  
  37.  import java.util.ArrayList;
  38.  import java.util.HashMap;
  39.  
  40.  /**
  41.   * Created by alimjan on 2017/07/13.
  42.   */
  43.  public class ShoppingCartActivity extends Activity implements OnClickListener {
  44.  
  45.      private final static String TAG = "ShoppingCartActivity";
  46.      private ImageView iv_menu;
  47.      private TextView tv_title;
  48.      private TextView tv_count;
  49.      private TextView tv_total_price;
  50.      private LinearLayout ll_content;
  51.      private LinearLayout ll_cart;
  52.      private LinearLayout ll_empty;
  53.      private int mCount;
  54.  
  55.      @Override
  56.      protected void onCreate(Bundle savedInstanceState) {
  57.          super.onCreate(savedInstanceState);
  58.          requestWindowFeature(Window.FEATURE_NO_TITLE);
  59.          setContentView(R.layout.activity_shopping_cart);
  60.          iv_menu = (ImageView) findViewById(R.id.iv_menu);
  61.          tv_title = (TextView) findViewById(R.id.tv_title);
  62.          tv_count = (TextView) findViewById(R.id.tv_count);
  63.          tv_total_price = (TextView) findViewById(R.id.tv_total_price);
  64.          ll_content = (LinearLayout) findViewById(R.id.ll_content);
  65.          ll_cart = (LinearLayout) findViewById(R.id.ll_cart);
  66.          ll_empty = (LinearLayout) findViewById(R.id.ll_empty);
  67.  
  68.          iv_menu.setOnClickListener(this);
  69.          findViewById(R.id.btn_shopping_channel).setOnClickListener(this);
  70.          findViewById(R.id.btn_settle).setOnClickListener(this);
  71.          iv_menu.setVisibility(View.VISIBLE);
  72.          tv_title.setText("购物车");
  73.      }
  74.  
  75.      //显示购物车图标中的商品数量
  76.      private void showCount(int count) {
  77.          mCount = count;
  78.          tv_count.setText(""+mCount);
  79.          if (mCount == 0) {
  80.              ll_content.setVisibility(View.GONE);
  81.              ll_cart.removeAllViews();
  82.              ll_empty.setVisibility(View.VISIBLE);
  83.          } else {
  84.              ll_content.setVisibility(View.VISIBLE);
  85.              ll_empty.setVisibility(View.GONE);
  86.          }
  87.      }
  88.  
  89.      @Override
  90.      public void onClick(View v) {
  91.          if (v.getId() == R.id.iv_menu) {
  92.              openOptionsMenu();
  93.          } else if (v.getId() == R.id.btn_shopping_channel) {
  94.              Intent intent = new Intent(this, ShoppingChannelActivity.class);
  95.              startActivity(intent);
  96.          } else if (v.getId() == R.id.btn_settle) {
  97.              AlertDialog.Builder builder = new AlertDialog.Builder(this);
  98.              builder.setTitle("结算商品");
  99.              builder.setMessage("客官抱歉，支付功能尚未开通，请下次再来");
  100.              builder.setPositiveButton("我知道了", null);
  101.              builder.create().show();
  102.          }
  103.      }
  104.  
  105.      @Override
  106.      public boolean onCreateOptionsMenu(Menu menu) {
  107.          getMenuInflater().inflate(R.menu.menu_cart, menu);
  108.          return true;
  109.      }
  110.  
  111.      @Override
  112.      public boolean onOptionsItemSelected(MenuItem item) {
  113.          int id = item.getItemId();
  114.          if (id == R.id.menu_shopping) {
  115.              Intent intent = new Intent(this, ShoppingChannelActivity.class);
  116.              startActivity(intent);
  117.          } else if (id == R.id.menu_clear) {
  118.              //清空购物车数据库
  119.              mCartHelper.deleteAll();
  120.              ll_cart.removeAllViews();
  121.              SharedUtil.getIntance(this).writeShared("count", "0");
  122.              showCount(0);
  123.              mCartGoods.clear();
  124.              mGoodsMap.clear();
  125.              Toast.makeText(this, "购物车已清空", Toast.LENGTH_SHORT).show();
  126.          } else if (id == R.id.menu_return) {
  127.              finish();
  128.          }
  129.          return true;
  130.      }
  131.  
  132.      private HashMap<Integer, CartInfo> mCartGoods = new HashMap<Integer, CartInfo>();
  133.      private View mContextView;
  134.      @Override
  135.      public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
  136.          mContextView = v;
  137.          getMenuInflater().inflate(R.menu.menu_goods, menu);
  138.      }
  139.  
  140.      @Override
  141.      public boolean onContextItemSelected(MenuItem item) {
  142.          CartInfo info = mCartGoods.get(mContextView.getId());
  143.          int id = item.getItemId();
  144.          if (id == R.id.menu_detail) {
  145.              //跳转到查看商品详情页面
  146.              goDetail(info.goods_id);
  147.          } else if (id == R.id.menu_delete) {
  148.              //从购物车删除商品的数据库操作
  149.              long goods_id = info.goods_id;
  150.              mCartHelper.delete("goods_id="+goods_id);
  151.              ll_cart.removeView(mContextView);
  152.              //更新购物车中的商品数量
  153.              int left_count = mCount-info.count;
  154.              for (int i=0; i<mCartArray.size(); i++) {
  155.                  if (goods_id == mCartArray.get(i).goods_id) {
  156.                      left_count = mCount-mCartArray.get(i).count;
  157.                      mCartArray.remove(i);
  158.                      break;
  159.                  }
  160.              }
  161.              SharedUtil.getIntance(this).writeShared("count", ""+left_count);
  162.              showCount(left_count);
  163.              Toast.makeText(this, "已从购物车删除"+mGoodsMap.get(goods_id).name, Toast.LENGTH_SHORT).show();
  164.              mGoodsMap.remove(goods_id);
  165.              refreshTotalPrice();
  166.          }
  167.          return true;
  168.      }
  169.  
  170.      private void goDetail(long rowid) {
  171.          Intent intent = new Intent(this, ShoppingDetailActivity.class);
  172.          intent.putExtra("goods_id", rowid);
  173.          startActivity(intent);
  174.      }
  175.  
  176.      private GoodsDBHelper mGoodsHelper;
  177.      private CartDBHelper mCartHelper;
  178.      private String mFirst = "true";
  179.  
  180.      @Override
  181.      protected void onResume() {
  182.          super.onResume();
  183.          mCount = Integer.parseInt(SharedUtil.getIntance(this).readShared("count", "0"));
  184.          showCount(mCount);
  185.          mGoodsHelper = GoodsDBHelper.getInstance(this, 1);
  186.          mGoodsHelper.openWriteLink();
  187.          mCartHelper = CartDBHelper.getInstance(this, 1);
  188.          mCartHelper.openWriteLink();
  189.          mFirst = SharedUtil.getIntance(this).readShared("first", "true");
  190.          downloadGoods();
  191.          SharedUtil.getIntance(this).writeShared("first", "false");
  192.          showCart();
  193.      }
  194.  
  195.      @Override
  196.      protected void onPause() {
  197.          super.onPause();
  198.          mGoodsHelper.closeLink();
  199.          mCartHelper.closeLink();
  200.      }
  201.  
  202.      private int mBeginViewId = 0x7F24FFF0;
  203.      private ArrayList<CartInfo> mCartArray = new ArrayList<CartInfo>();
  204.      private HashMap<Long, GoodsInfo> mGoodsMap = new HashMap<Long, GoodsInfo>();
  205.      private void showCart() {
  206.          mCartArray = mCartHelper.query("1=1");
  207.          Log.d(TAG, "mCartArray.size()="+mCartArray.size());
  208.          if (mCartArray==null || mCartArray.size()<=0) {
  209.              return;
  210.          }
  211.          ll_cart.removeAllViews();
  212.          LinearLayout ll_row = newLinearLayout(LinearLayout.HORIZONTAL, LayoutParams.WRAP_CONTENT);
  213.          ll_row.addView(newTextView(0, 2, Gravity.CENTER, "图片", Color.BLACK, 15));
  214.          ll_row.addView(newTextView(0, 3, Gravity.CENTER, "名称", Color.BLACK, 15));
  215.          ll_row.addView(newTextView(0, 1, Gravity.CENTER, "数量", Color.BLACK, 15));
  216.          ll_row.addView(newTextView(0, 1, Gravity.CENTER, "单价", Color.BLACK, 15));
  217.          ll_row.addView(newTextView(0, 1, Gravity.CENTER, "总价", Color.BLACK, 15));
  218.          ll_cart.addView(ll_row);
  219.          for (int i=0; i<mCartArray.size(); i++) {
  220.              final CartInfo info = mCartArray.get(i);
  221.              GoodsInfo goods = mGoodsHelper.queryById(info.goods_id);
  222.              Log.d(TAG, "name="+goods.name+",price="+goods.price+",desc="+goods.desc);
  223.              mGoodsMap.put(info.goods_id, goods);
  224.              ll_row = newLinearLayout(LinearLayout.HORIZONTAL, LayoutParams.WRAP_CONTENT);
  225.              ll_row.setId(mBeginViewId+i);
  226.              //添加商品小图
  227.              ImageView iv_thumb = new ImageView(this);
  228.              LinearLayout.LayoutParams iv_params = new LinearLayout.LayoutParams(
  229.                      0, LayoutParams.WRAP_CONTENT, 2);
  230.              iv_thumb.setLayoutParams(iv_params);
  231.              iv_thumb.setScaleType(ScaleType.FIT_CENTER);
  232.              iv_thumb.setImageBitmap(MainApplication.getInstance().mIconMap.get(info.goods_id));
  233.              ll_row.addView(iv_thumb);
  234.              //添加商品名称与描述
  235.              LinearLayout ll_name = new LinearLayout(this);
  236.              LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
  237.                      0, LayoutParams.MATCH_PARENT, 3);
  238.              ll_name.setLayoutParams(params);
  239.              ll_name.setOrientation(LinearLayout.VERTICAL);
  240.              ll_name.addView(newTextView(-3, 1, Gravity.LEFT, goods.name, Color.BLACK, 17));
  241.              ll_name.addView(newTextView(-3, 1, Gravity.LEFT, goods.desc, Color.GRAY, 12));
  242.              ll_row.addView(ll_name);
  243.              //添加商品数量、单价和总价
  244.              ll_row.addView(newTextView(1, 1, Gravity.CENTER, ""+info.count, Color.BLACK, 17));
  245.              ll_row.addView(newTextView(1, 1, Gravity.RIGHT, ""+(int)goods.price, Color.BLACK, 15));
  246.              ll_row.addView(newTextView(1, 1, Gravity.RIGHT, ""+(int)(info.count*goods.price), Color.RED, 17));
  247.              //给商品行添加点击事件
  248.              ll_row.setOnClickListener(new OnClickListener() {
  249.                  @Override
  250.                  public void onClick(View v) {
  251.                      goDetail(info.goods_id);
  252.                  }
  253.              });
  254.              //给商品行注册上下文菜单
  255.              unregisterForContextMenu(ll_row);
  256.              registerForContextMenu(ll_row);
  257.              mCartGoods.put(ll_row.getId(), info);
  258.              ll_cart.addView(ll_row);
  259.          }
  260.          refreshTotalPrice();
  261.      }
  262.  
  263.      private void refreshTotalPrice() {
  264.          int total_price = 0;
  265.          for (CartInfo info : mCartArray) {
  266.              GoodsInfo goods = mGoodsMap.get(info.goods_id);
  267.              total_price += goods.price*info.count;
  268.          }
  269.          tv_total_price.setText(""+total_price);
  270.      }
  271.  
  272.      private LinearLayout newLinearLayout(int orientation, int height) {
  273.          LinearLayout ll_new = new LinearLayout(this);
  274.          LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
  275.                  LayoutParams.MATCH_PARENT, height);
  276.          //params.setMargins(2, 2, 2, 2);
  277.          ll_new.setLayoutParams(params);
  278.          ll_new.setOrientation(orientation);
  279.          ll_new.setBackgroundColor(Color.WHITE);
  280.          return ll_new;
  281.      }
  282.  
  283.      private TextView newTextView(int height, float weight, int gravity, String text, int textColor, int textSize) {
  284.          TextView tv_new = new TextView(this);
  285.          if (height == -3) {  //垂直排列
  286.              LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
  287.                      LayoutParams.MATCH_PARENT, 0, weight);
  288.              tv_new.setLayoutParams(params);
  289.          } else {  //水平排列
  290.              LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
  291.                      0, (height==0)?LayoutParams.WRAP_CONTENT:LayoutParams.MATCH_PARENT, weight);
  292.              tv_new.setLayoutParams(params);
  293.          }
  294.          tv_new.setText(text);
  295.          tv_new.setTextColor(textColor);
  296.          tv_new.setTextSize(TypedValue.COMPLEX_UNIT_SP, textSize);
  297.          tv_new.setGravity(Gravity.CENTER|gravity);
  298.          return tv_new;
  299.      }
  300.  
  301.      private String[] mNameArray = {
  302.              "iphone7", "Mate8", "小米5", "vivo X6S", "OPPO R9plus", "魅族Pro6"
  303.              };
  304.      private String[] mDescArray = {
  305.              "Apple iPhone 7 128GB 玫瑰金色 移动联通电信4G手机",
  306.              "华为 HUAWEI Mate8 3GB+32GB版 移动联通4G手机（月光银）",
  307.              "小米手机5 全网通 高配版 3GB内存 64GB 白色",
  308.              "vivo X6S 金色 全网通4G 双卡双待 4GB+64GB",
  309.              "OPPO R9plus 4GB+64GB内存版 金色 全网通4G手机 双卡双待",
  310.              "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"
  311.              };
  312.      private float[] mPriceArray = {5888, 2499, 1799, 2298, 2499, 2199};
  313.      private int[] mThumbArray = {
  314.              R.drawable.iphone_s, R.drawable.huawei_s, R.drawable.xiaomi_s,
  315.              R.drawable.vivo_s, R.drawable.oppo_9p_s, R.drawable.meizu_s
  316.              };
  317.      private int[] mPicArray = {
  318.              R.drawable.iphone, R.drawable.huawei, R.drawable.xiaomi,
  319.              R.drawable.vivo, R.drawable.oppo_9p, R.drawable.meizu
  320.              };
  321.      //模拟网络数据，初始化数据库中的商品信息
  322.      private void downloadGoods() {
  323.          String path = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS) + "/";
  324.          if (mFirst.equals("true")) {
  325.              for (int i=0; i<mNameArray.length; i++) {
  326.                  GoodsInfo info = new GoodsInfo();
  327.                  info.name = mNameArray[i];
  328.                  info.desc = mDescArray[i];
  329.                  info.price = mPriceArray[i];
  330.                  long rowid = mGoodsHelper.insert(info);
  331.                  info.rowid = rowid;
  332.                  //往全局内存写入商品小图
  333.                  Bitmap thumb = BitmapFactory.decodeResource(getResources(), mThumbArray[i]);
  334.                  MainApplication.getInstance().mIconMap.put(rowid, thumb);
  335.                  String thumb_path = path + rowid + "_s.jpg";
  336.                  FileUtil.saveImage(thumb_path, thumb);
  337.                  info.thumb_path = thumb_path;
  338.                  //往SD卡保存商品大图
  339.                  Bitmap pic = BitmapFactory.decodeResource(getResources(), mPicArray[i]);
  340.                  String pic_path = path + rowid + ".jpg";
  341.                  FileUtil.saveImage(pic_path, pic);
  342.                  pic.recycle();
  343.                  info.pic_path = pic_path;
  344.                  mGoodsHelper.update(info);
  345.              }
  346.          } else {
  347.              ArrayList<GoodsInfo> goodsArray = mGoodsHelper.query("1=1");
  348.              for (int i=0; i<goodsArray.size(); i++) {
  349.                  GoodsInfo info = goodsArray.get(i);
  350.                  Bitmap thumb = BitmapFactory.decodeFile(info.thumb_path);
  351.                  MainApplication.getInstance().mIconMap.put(info.rowid, thumb);
  352.              }
  353.          }
  354.      }
  355.  
  356.      public static void startHome(Context mContext) {
  357.          Intent intent = new Intent(mContext, ShoppingCartActivity.class);
  358.          mContext.startActivity(intent);
  359.      }
  360.  
  361.  }
  1. ShoppingChannelActivity:
  1.  package com.example.alimjan.hello_world;
  2.  
  3.  import android.content.Intent;
  4.  import android.graphics.Color;
  5.  import android.os.Bundle;
  6.  import android.support.v7.app.AppCompatActivity;
  7.  import android.util.TypedValue;
  8.  import android.view.Gravity;
  9.  import android.view.View;
  10.  import android.view.View.OnClickListener;
  11.  import android.widget.Button;
  12.  import android.widget.ImageView;
  13.  import android.widget.ImageView.ScaleType;
  14.  import android.widget.LinearLayout;
  15.  import android.widget.LinearLayout.LayoutParams;
  16.  import android.widget.TextView;
  17.  import android.widget.Toast;
  18.  
  19.  import com.example.alimjan.hello_world.bean.CartInfo;
  20.  import com.example.alimjan.hello_world.bean.GoodsInfo;
  21.  import com.example.alimjan.hello_world.dataBase.CartDBHelper;
  22.  import com.example.alimjan.hello_world.dataBase.GoodsDBHelper;
  23.  import com.example.alimjan.hello_world.Utils.DateUtil;
  24.  import com.example.alimjan.hello_world.Utils.SharedUtil;
  25.  
  26.  import java.util.ArrayList;
  27.  
  28.  /**
  29.   * Created by alimjan on 2017/07/13.
  30.   */
  31.  public class ShoppingChannelActivity extends AppCompatActivity implements OnClickListener {
  32.  
  33.      private final static String TAG = "ShoppingChannelActivity";
  34.      private TextView tv_title;
  35.      private TextView tv_count;
  36.      private LinearLayout ll_channel;
  37.      private int mCount;
  38.  
  39.      @Override
  40.      protected void onCreate(Bundle savedInstanceState) {
  41.          super.onCreate(savedInstanceState);
  42.          setContentView(R.layout.activity_shopping_channel);
  43.          tv_title = (TextView) findViewById(R.id.tv_title);
  44.          tv_count = (TextView) findViewById(R.id.tv_count);
  45.          ll_channel = (LinearLayout) findViewById(R.id.ll_channel);
  46.          findViewById(R.id.iv_cart).setOnClickListener(this);
  47.          tv_title.setText("手机商场");
  48.      }
  49.  
  50.      @Override
  51.      public void onClick(View v) {
  52.          if (v.getId() == R.id.iv_cart) {
  53.              Intent intent = new Intent(this, ShoppingCartActivity.class);
  54.              startActivity(intent);
  55.          }
  56.      }
  57.  
  58.      private void addToCart(long goods_id) {
  59.          mCount++;
  60.          tv_count.setText(""+mCount);
  61.          SharedUtil.getIntance(this).writeShared("count", ""+mCount);
  62.          CartInfo info = mCartHelper.queryByGoodsId(goods_id);
  63.          if (info != null) {
  64.              info.count++;
  65.              info.update_time = DateUtil.getCurDateStr("");
  66.              mCartHelper.update(info);
  67.          } else {
  68.              info = new CartInfo();
  69.              info.goods_id = goods_id;
  70.              info.count = 1;
  71.              info.update_time = DateUtil.getCurDateStr("");
  72.              mCartHelper.insert(info);
  73.          }
  74.      }
  75.  
  76.      private GoodsDBHelper mGoodsHelper;
  77.      private CartDBHelper mCartHelper;
  78.  
  79.      @Override
  80.      protected void onResume() {
  81.          super.onResume();
  82.          mCount = Integer.parseInt(SharedUtil.getIntance(this).readShared("count", "0"));
  83.          tv_count.setText(""+mCount);
  84.          mGoodsHelper = GoodsDBHelper.getInstance(this, 1);
  85.          mGoodsHelper.openReadLink();
  86.          mCartHelper = CartDBHelper.getInstance(this, 1);
  87.          mCartHelper.openWriteLink();
  88.          //展示商品列表
  89.          showGoods();
  90.      }
  91.  
  92.      @Override
  93.      protected void onPause() {
  94.          super.onPause();
  95.          mGoodsHelper.closeLink();
  96.          mCartHelper.closeLink();
  97.      }
  98.  
  99.      private LayoutParams mFullParams, mHalfParams;
  100.      private void showGoods() {
  101.          ll_channel.removeAllViews();
  102.          mFullParams = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
  103.          mHalfParams = new LayoutParams(0, LayoutParams.WRAP_CONTENT, 1);
  104.          mHalfParams.setMargins(2, 2, 2, 2);
  105.          LinearLayout ll_row = newLinearLayout(LinearLayout.HORIZONTAL, 0);
  106.          ArrayList<GoodsInfo> goodsArray = mGoodsHelper.query("1=1");
  107.          int i=0;
  108.          for (; i<goodsArray.size(); i++) {
  109.              final GoodsInfo info = goodsArray.get(i);
  110.              LinearLayout ll_goods = newLinearLayout(LinearLayout.VERTICAL, 1);
  111.              ll_goods.setBackgroundColor(Color.WHITE);
  112.              //添加商品标题
  113.              TextView tv_name = new TextView(this);
  114.              tv_name.setLayoutParams(mFullParams);
  115.              tv_name.setGravity(Gravity.CENTER);
  116.              tv_name.setText(info.name);
  117.              tv_name.setTextColor(Color.BLACK);
  118.              tv_name.setTextSize(TypedValue.COMPLEX_UNIT_SP, 17);
  119.              ll_goods.addView(tv_name);
  120.              //添加商品小图
  121.              ImageView iv_thumb = new ImageView(this);
  122.              iv_thumb.setLayoutParams(new LayoutParams(
  123.                      LayoutParams.MATCH_PARENT, 200));
  124.              iv_thumb.setScaleType(ScaleType.FIT_CENTER);
  125.              iv_thumb.setImageBitmap(MainApplication.getInstance().mIconMap.get(info.rowid));
  126.              iv_thumb.setOnClickListener(new OnClickListener() {
  127.                  @Override
  128.                  public void onClick(View v) {
  129.                      Intent intent = new Intent(ShoppingChannelActivity.this, ShoppingDetailActivity.class);
  130.                      intent.putExtra("goods_id", info.rowid);
  131.                      startActivity(intent);
  132.                  }
  133.              });
  134.              ll_goods.addView(iv_thumb);
  135.              //添加商品价格
  136.              LinearLayout ll_bottom = newLinearLayout(LinearLayout.HORIZONTAL, 0);
  137.              TextView tv_price = new TextView(this);
  138.              tv_price.setLayoutParams(new LayoutParams(0, LayoutParams.WRAP_CONTENT, 2));
  139.              tv_price.setGravity(Gravity.CENTER);
  140.              tv_price.setText(""+(int)info.price);
  141.              tv_price.setTextColor(Color.RED);
  142.              tv_price.setTextSize(TypedValue.COMPLEX_UNIT_SP, 15);
  143.              ll_bottom.addView(tv_price);
  144.              //添加购物车按钮
  145.              Button btn_add = new Button(this);
  146.              btn_add.setLayoutParams(new LayoutParams(0, LayoutParams.WRAP_CONTENT, 3));
  147.              btn_add.setGravity(Gravity.CENTER);
  148.              btn_add.setText("加入购物车");
  149.              btn_add.setTextColor(Color.BLACK);
  150.              btn_add.setTextSize(TypedValue.COMPLEX_UNIT_SP, 15);
  151.              btn_add.setOnClickListener(new OnClickListener() {
  152.                  @Override
  153.                  public void onClick(View v) {
  154.                      addToCart(info.rowid);
  155.                      Toast.makeText(ShoppingChannelActivity.this,
  156.                              "已添加一部"+info.name+"到购物车", Toast.LENGTH_SHORT).show();
  157.                  }
  158.              });
  159.              ll_bottom.addView(btn_add);
  160.              ll_goods.addView(ll_bottom);
  161.              //添加商品项目
  162.              ll_row.addView(ll_goods);
  163.              if (i%2 == 1) {
  164.                  ll_channel.addView(ll_row);
  165.                  ll_row = newLinearLayout(LinearLayout.HORIZONTAL, 0);
  166.              }
  167.          }
  168.          if (i%2 == 0) {
  169.              ll_row.addView(newLinearLayout(LinearLayout.VERTICAL, 1));
  170.              ll_channel.addView(ll_row);
  171.          }
  172.      }
  173.  
  174.      private LinearLayout newLinearLayout(int orientation, int weight) {
  175.          LinearLayout ll_new = new LinearLayout(this);
  176.          ll_new.setLayoutParams((weight==0)?mFullParams:mHalfParams);
  177.          ll_new.setOrientation(orientation);
  178.          return ll_new;
  179.      }
  180.  
  181.  }
  1. ShoppingDetailActivity:
  1.  package com.example.alimjan.hello_world;
  2.  
  3.  import android.content.Intent;
  4.  import android.graphics.Bitmap;
  5.  import android.graphics.BitmapFactory;
  6.  import android.os.Bundle;
  7.  import android.support.v7.app.AppCompatActivity;
  8.  import android.view.View;
  9.  import android.view.View.OnClickListener;
  10.  import android.widget.ImageView;
  11.  import android.widget.TextView;
  12.  import android.widget.Toast;
  13.  
  14.  import com.example.alimjan.hello_world.bean.CartInfo;
  15.  import com.example.alimjan.hello_world.bean.GoodsInfo;
  16.  import com.example.alimjan.hello_world.dataBase.CartDBHelper;
  17.  import com.example.alimjan.hello_world.dataBase.GoodsDBHelper;
  18.  import com.example.alimjan.hello_world.Utils.DateUtil;
  19.  import com.example.alimjan.hello_world.Utils.SharedUtil;
  20.  
  21.  /**
  22.   * Created by alimjan on 2017/07/13.
  23.   */
  24.  public class ShoppingDetailActivity extends AppCompatActivity implements OnClickListener {
  25.  
  26.      private TextView tv_title;
  27.      private TextView tv_count;
  28.      private TextView tv_goods_price;
  29.      private TextView tv_goods_desc;
  30.      private ImageView iv_goods_pic;
  31.      private int mCount;
  32.      private long mGoodsId;
  33.  
  34.      @Override
  35.      protected void onCreate(Bundle savedInstanceState) {
  36.          super.onCreate(savedInstanceState);
  37.          setContentView(R.layout.activity_shopping_detail);
  38.          tv_title = (TextView) findViewById(R.id.tv_title);
  39.          tv_count = (TextView) findViewById(R.id.tv_count);
  40.          tv_goods_price = (TextView) findViewById(R.id.tv_goods_price);
  41.          tv_goods_desc = (TextView) findViewById(R.id.tv_goods_desc);
  42.          iv_goods_pic = (ImageView) findViewById(R.id.iv_goods_pic);
  43.          findViewById(R.id.iv_cart).setOnClickListener(this);
  44.          findViewById(R.id.btn_add_cart).setOnClickListener(this);
  45.  
  46.          mCount = Integer.parseInt(SharedUtil.getIntance(this).readShared("count", "0"));
  47.          tv_count.setText(""+mCount);
  48.      }
  49.  
  50.      @Override
  51.      public void onClick(View v) {
  52.          if (v.getId() == R.id.iv_cart) {
  53.              Intent intent = new Intent(this, ShoppingCartActivity.class);
  54.              startActivity(intent);
  55.          } else if (v.getId() == R.id.btn_add_cart) {
  56.              //添加购物车数据库
  57.              addToCart(mGoodsId);
  58.              Toast.makeText(this, "成功添加至购物车", Toast.LENGTH_SHORT).show();
  59.          }
  60.      }
  61.  
  62.      private void addToCart(long goods_id) {
  63.          mCount++;
  64.          tv_count.setText(""+mCount);
  65.          SharedUtil.getIntance(this).writeShared("count", ""+mCount);
  66.          CartInfo info = mCartHelper.queryByGoodsId(goods_id);
  67.          if (info != null) {
  68.              info.count++;
  69.              info.update_time = DateUtil.getCurDateStr("");
  70.              mCartHelper.update(info);
  71.          } else {
  72.              info = new CartInfo();
  73.              info.goods_id = goods_id;
  74.              info.count = 1;
  75.              info.update_time = DateUtil.getCurDateStr("");
  76.              mCartHelper.insert(info);
  77.          }
  78.      }
  79.  
  80.      private GoodsDBHelper mGoodsHelper;
  81.      private CartDBHelper mCartHelper;
  82.  
  83.      @Override
  84.      protected void onResume() {
  85.          super.onResume();
  86.          mGoodsHelper = GoodsDBHelper.getInstance(this, 1);
  87.          mGoodsHelper.openReadLink();
  88.          mCartHelper = CartDBHelper.getInstance(this, 1);
  89.          mCartHelper.openWriteLink();
  90.          //展示商品信息
  91.          showDetail();
  92.      }
  93.  
  94.      @Override
  95.      protected void onPause() {
  96.          super.onPause();
  97.          mGoodsHelper.closeLink();
  98.          mCartHelper.closeLink();
  99.      }
  100.  
  101.      private void showDetail() {
  102.          mGoodsId = getIntent().getLongExtra("goods_id", 0l);
  103.          if (mGoodsId > 0) {
  104.              GoodsInfo info = mGoodsHelper.queryById(mGoodsId);
  105.              tv_title.setText(info.name);
  106.              tv_goods_desc.setText(info.desc);
  107.              tv_goods_price.setText(""+info.price);
  108.              Bitmap pic = BitmapFactory.decodeFile(info.pic_path);
  109.              iv_goods_pic.setImageBitmap(pic);
  110.          }
  111.      }
  112.  
  113.  }
  1. activity_shopping_cart.xml
  1.  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  2.      android:layout_width="match_parent"
  3.      android:layout_height="match_parent"
  4.      android:background="#ffffdd"
  5.      android:orientation="vertical" >
  6.  
  7.      <include layout="@layout/activity_shopping_title" />
  8.  
  9.      <ScrollView
  10.          android:layout_width="match_parent"
  11.          android:layout_height="wrap_content" >
  12.  
  13.          <FrameLayout
  14.              android:layout_width="match_parent"
  15.              android:layout_height="wrap_content"
  16.              android:padding="5dp" >
  17.  
  18.              <LinearLayout
  19.                  android:id="@+id/ll_content"
  20.                  android:layout_width="match_parent"
  21.                  android:layout_height="wrap_content"
  22.                  android:orientation="vertical"
  23.                  android:visibility="gone" >
  24.  
  25.                  <LinearLayout
  26.                      android:id="@+id/ll_cart"
  27.                      android:layout_width="match_parent"
  28.                      android:layout_height="wrap_content"
  29.                      android:orientation="vertical" >
  30.                  </LinearLayout>
  31.  
  32.                  <LinearLayout
  33.                      android:layout_width="match_parent"
  34.                      android:layout_height="wrap_content"
  35.                      android:orientation="horizontal"
  36.                      android:padding="10dp" >
  37.  
  38.                      <TextView
  39.                          android:layout_width="0dp"
  40.                          android:layout_height="wrap_content"
  41.                          android:layout_weight="1"
  42.                          android:gravity="center|right"
  43.                          android:text="总金额："
  44.                          android:textColor="@color/black"
  45.                          android:textSize="17sp" />
  46.  
  47.                      <TextView
  48.                          android:id="@+id/tv_total_price"
  49.                          android:layout_width="0dp"
  50.                          android:layout_height="wrap_content"
  51.                          android:layout_weight="2"
  52.                          android:gravity="center|left"
  53.                          android:textColor="@color/red"
  54.                          android:textSize="25sp" />
  55.  
  56.                      <Button
  57.                          android:id="@+id/btn_settle"
  58.                          android:layout_width="0dp"
  59.                          android:layout_height="wrap_content"
  60.                          android:layout_weight="1"
  61.                          android:gravity="center"
  62.                          android:text="结算"
  63.                          android:textColor="@color/black"
  64.                          android:textSize="20sp" />
  65.                  </LinearLayout>
  66.  
  67.              </LinearLayout>
  68.  
  69.              <LinearLayout
  70.                  android:id="@+id/ll_empty"
  71.                  android:layout_width="match_parent"
  72.                  android:layout_height="wrap_content"
  73.                  android:orientation="vertical"
  74.                  android:visibility="gone" >
  75.  
  76.                  <TextView
  77.                      android:layout_width="match_parent"
  78.                      android:layout_height="wrap_content"
  79.                      android:layout_marginBottom="100dp"
  80.                      android:layout_marginTop="100dp"
  81.                      android:gravity="center"
  82.                      android:text="哎呀，购物车空空如也，快去选购商品吧"
  83.                      android:textColor="@color/black"
  84.                      android:textSize="17sp" />
  85.  
  86.                  <Button
  87.                      android:id="@+id/btn_shopping_channel"
  88.                      android:layout_width="match_parent"
  89.                      android:layout_height="wrap_content"
  90.                      android:gravity="center"
  91.                      android:text="逛逛手机商场"
  92.                      android:textColor="@color/black"
  93.                      android:textSize="17sp" />
  94.              </LinearLayout>
  95.          </FrameLayout>
  96.      </ScrollView>
  97.  
  98.  </LinearLayout>
  1. activity_shopping_channel.xml
  1.  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  2.      android:layout_width="match_parent"
  3.      android:layout_height="match_parent"
  4.      android:background="#ffffdd"
  5.      android:orientation="vertical" >
  6.  
  7.      <include layout="@layout/activity_shopping_title" />
  8.  
  9.      <ScrollView
  10.          android:layout_width="match_parent"
  11.          android:layout_height="wrap_content" >
  12.  
  13.          <LinearLayout
  14.              android:id="@+id/ll_channel"
  15.              android:layout_width="match_parent"
  16.              android:layout_height="wrap_content"
  17.              android:padding="5dp"
  18.              android:orientation="vertical" >
  19.          </LinearLayout>
  20.      </ScrollView>
  21.  
  22.  </LinearLayout>
  1.  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  2.      android:layout_width="match_parent"
  3.      android:layout_height="match_parent"
  4.      android:background="#ffffdd"
  5.      android:orientation="vertical" >
  6.  
  7.      <include layout="@layout/activity_shopping_title" />
  8.  
  9.      <ScrollView
  10.          android:layout_width="match_parent"
  11.          android:layout_height="wrap_content" >
  12.  
  13.          <LinearLayout
  14.              android:layout_width="match_parent"
  15.              android:layout_height="wrap_content"
  16.              android:padding="5dp"
  17.              android:orientation="vertical" >
  18.  
  19.              <ImageView
  20.                  android:id="@+id/iv_goods_pic"
  21.                  android:layout_width="match_parent"
  22.                  android:layout_height="400dp"
  23.                  android:scaleType="fitCenter" />
  24.  
  25.              <TextView
  26.                  android:id="@+id/tv_goods_price"
  27.                  android:layout_width="match_parent"
  28.                  android:layout_height="wrap_content"
  29.                  android:textColor="@color/red"
  30.                  android:textSize="22sp" />
  31.  
  32.              <TextView
  33.                  android:id="@+id/tv_goods_desc"
  34.                  android:layout_width="match_parent"
  35.                  android:layout_height="wrap_content"
  36.                  android:textColor="@color/black"
  37.                  android:textSize="15sp" />
  38.  
  39.              <Button
  40.                  android:id="@+id/btn_add_cart"
  41.                  android:layout_width="match_parent"
  42.                  android:layout_height="wrap_content"
  43.                  android:text="加入购物车"
  44.                  android:textColor="@color/black"
  45.                  android:textSize="17sp" />
  46.          </LinearLayout>
  47.      </ScrollView>
  48.  
  49.  </LinearLayout>

　　一些工具类：

  1.  package com.example.alimjan.hello_world.Utils;
  2.  
  3.  import android.graphics.Bitmap;
  4.  import android.graphics.BitmapFactory;
  5.  
  6.  import java.io.BufferedInputStream;
  7.  import java.io.BufferedOutputStream;
  8.  import java.io.File;
  9.  import java.io.FileInputStream;
  10.  import java.io.FileOutputStream;
  11.  import java.io.FilenameFilter;
  12.  import java.util.ArrayList;
  13.  import java.util.Locale;
  14.  
  15.  public class FileUtil {
  16.  
  17.      public static void saveText(String path, String txt) {
  18.          try {
  19.              FileOutputStream fos = new FileOutputStream(path);
  20.              fos.write(txt.getBytes());
  21.              fos.close();
  22.          } catch (Exception e) {
  23.              e.printStackTrace();
  24.          }
  25.      }
  26.  
  27.      public static String openText(String path) {
  28.          String readStr = "";
  29.          try {
  30.              FileInputStream fis = new FileInputStream(path);
  31.              byte[] b = new byte[fis.available()];
  32.              fis.read(b);
  33.              readStr = new String(b);
  34.              fis.close();
  35.          } catch (Exception e) {
  36.              e.printStackTrace();
  37.          }
  38.          return readStr;
  39.      }
  40.  
  41.      public static void saveImage(String path, Bitmap bitmap) {
  42.          try {
  43.              BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(path));
  44.              bitmap.compress(Bitmap.CompressFormat.JPEG, 80, bos);
  45.              bos.flush();
  46.              bos.close();
  47.          } catch (Exception e) {
  48.              e.printStackTrace();
  49.          }
  50.      }
  51.  
  52.      public static Bitmap openImage(String path) {
  53.          Bitmap bitmap = null;
  54.          try {
  55.              BufferedInputStream bis = new BufferedInputStream(new FileInputStream(path));
  56.              bitmap = BitmapFactory.decodeStream(bis);
  57.              bis.close();
  58.          } catch (Exception e) {
  59.              e.printStackTrace();
  60.          }
  61.          return bitmap;
  62.      }
  63.  
  64.      public static ArrayList<File> getFileList(String path, String[] extendArray) {
  65.          ArrayList<File> displayedContent = new ArrayList<File>();
  66.          File[] files = null;
  67.          File directory = new File(path);
  68.          if (extendArray != null && extendArray.length>0) {
  69.              FilenameFilter fileFilter = getTypeFilter(extendArray);
  70.              files = directory.listFiles(fileFilter);
  71.          } else {
  72.              files = directory.listFiles();
  73.          }
  74.  
  75.          if (files != null) {
  76.              for (File f : files) {
  77.                  if (!f.isDirectory() && !f.isHidden()) {
  78.                      displayedContent.add(f);
  79.                  }
  80.              }
  81.          }
  82.          return displayedContent;
  83.      }
  84.  
  85.      public static FilenameFilter getTypeFilter(String[] extendArray) {
  86.          final ArrayList<String> fileExtensions = new ArrayList<String>();
  87.          for (int i=0; i<extendArray.length; i++) {
  88.              fileExtensions.add(extendArray[i]);
  89.          }
  90.          FilenameFilter fileNameFilter = new FilenameFilter() {
  91.              @Override
  92.              public boolean accept(File directory, String fileName) {
  93.                  boolean matched = false;
  94.                  File f = new File(String.format("%s/%s",
  95.                          directory.getAbsolutePath(), fileName));
  96.                  matched = f.isDirectory();
  97.                  if (!matched) {
  98.                      for (String s : fileExtensions) {
  99.                          s = String.format(".{0,}\\%s$", s);
  100.                          s = s.toUpperCase(Locale.getDefault());
  101.                          fileName = fileName.toUpperCase(Locale.getDefault());
  102.                          matched = fileName.matches(s);
  103.                          if (matched) {
  104.                              break;
  105.                          }
  106.                      }
  107.                  }
  108.                  return matched;
  109.              }
  110.          };
  111.          return fileNameFilter;
  112.      }
  113.  
  114.  }
  1.  package com.example.alimjan.hello_world.dataBase;
  2.  
  3.  import android.content.ContentValues;
  4.  import android.content.Context;
  5.  import android.database.Cursor;
  6.  import android.database.sqlite.SQLiteDatabase;
  7.  import android.database.sqlite.SQLiteOpenHelper;
  8.  import android.util.Log;
  9.  
  10.  import com.example.alimjan.hello_world.bean.GoodsInfo;
  11.  
  12.  import java.util.ArrayList;
  13.  
  14.  public class GoodsDBHelper extends SQLiteOpenHelper {
  15.      private static final String TAG = "GoodsDBHelper";
  16.      private static final String DB_NAME = "goods.db";
  17.      private static final int DB_VERSION = 1;
  18.      private static GoodsDBHelper mHelper = null;
  19.      private SQLiteDatabase mDB = null;
  20.      private static final String TABLE_NAME = "goods_info";
  21.  
  22.      private GoodsDBHelper(Context context) {
  23.          super(context, DB_NAME, null, DB_VERSION);
  24.      }
  25.  
  26.      private GoodsDBHelper(Context context, int version) {
  27.          super(context, DB_NAME, null, version);
  28.      }
  29.  
  30.      public static GoodsDBHelper getInstance(Context context, int version) {
  31.          if (version > 0 && mHelper == null) {
  32.              mHelper = new GoodsDBHelper(context, version);
  33.          } else if (mHelper == null) {
  34.              mHelper = new GoodsDBHelper(context);
  35.          }
  36.          return mHelper;
  37.      }
  38.  
  39.      public SQLiteDatabase openReadLink() {
  40.          if (mDB == null || mDB.isOpen() != true) {
  41.              mDB = mHelper.getReadableDatabase();
  42.          }
  43.          return mDB;
  44.      }
  45.  
  46.      public SQLiteDatabase openWriteLink() {
  47.          if (mDB == null || mDB.isOpen() != true) {
  48.              mDB = mHelper.getWritableDatabase();
  49.          }
  50.          return mDB;
  51.      }
  52.  
  53.      public void closeLink() {
  54.          if (mDB != null && mDB.isOpen() == true) {
  55.              mDB.close();
  56.              mDB = null;
  57.          }
  58.      }
  59.  
  60.      public String getDBName() {
  61.          if (mHelper != null) {
  62.              return mHelper.getDatabaseName();
  63.          } else {
  64.              return DB_NAME;
  65.          }
  66.      }
  67.  
  68.      @Override
  69.      public void onCreate(SQLiteDatabase db) {
  70.          Log.d(TAG, "onCreate");
  71.          String drop_sql = "DROP TABLE IF EXISTS " + TABLE_NAME + ";";
  72.          Log.d(TAG, "drop_sql:" + drop_sql);
  73.          db.execSQL(drop_sql);
  74.          String create_sql = "CREATE TABLE IF NOT EXISTS " + TABLE_NAME + " ("
  75.                  + "_id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,"
  76.                  + "name VARCHAR NOT NULL," + "desc VARCHAR NOT NULL,"
  77.                  + "price FLOAT NOT NULL," + "thumb_path VARCHAR NOT NULL,"
  78.                  + "pic_path VARCHAR NOT NULL"
  79.                  + ");";
  80.          Log.d(TAG, "create_sql:" + create_sql);
  81.          db.execSQL(create_sql);
  82.      }
  83.  
  84.      @Override
  85.      public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
  86.      }
  87.  
  88.      public int delete(String condition) {
  89.          int count = mDB.delete(TABLE_NAME, condition, null);
  90.          return count;
  91.      }
  92.  
  93.      public int deleteAll() {
  94.          int count = mDB.delete(TABLE_NAME, "1=1", null);
  95.          return count;
  96.      }
  97.  
  98.      public long insert(GoodsInfo info) {
  99.          ArrayList<GoodsInfo> infoArray = new ArrayList<GoodsInfo>();
  100.          infoArray.add(info);
  101.          return insert(infoArray);
  102.      }
  103.  
  104.      public long insert(ArrayList<GoodsInfo> infoArray) {
  105.          long result = -1;
  106.          for (int i = 0; i < infoArray.size(); i++) {
  107.              GoodsInfo info = infoArray.get(i);
  108.              // 如果存在相同rowid的记录，则更新记录
  109.              if (info.rowid > 0) {
  110.                  String condition = String.format("rowid='%d'", info.rowid);
  111.                  update(info, condition);
  112.                  result = info.rowid;
  113.                  continue;
  114.              }
  115.              // 不存在唯一性重复的记录，则插入新记录
  116.              ContentValues cv = new ContentValues();
  117.              cv.put("name", info.name);
  118.              cv.put("desc", info.desc);
  119.              cv.put("price", info.price);
  120.              cv.put("thumb_path", info.thumb_path);
  121.              cv.put("pic_path", info.pic_path);
  122.              result = mDB.insert(TABLE_NAME, "", cv);
  123.              // 添加成功后返回行号，失败后返回-1
  124.              if (result == -1) {
  125.                  return result;
  126.              }
  127.          }
  128.          return result;
  129.      }
  130.  
  131.      public int update(GoodsInfo info, String condition) {
  132.          ContentValues cv = new ContentValues();
  133.          cv.put("name", info.name);
  134.          cv.put("desc", info.desc);
  135.          cv.put("price", info.price);
  136.          cv.put("thumb_path", info.thumb_path);
  137.          cv.put("pic_path", info.pic_path);
  138.          int count = mDB.update(TABLE_NAME, cv, condition, null);
  139.          return count;
  140.      }
  141.  
  142.      public int update(GoodsInfo info) {
  143.          return update(info, "rowid="+info.rowid);
  144.      }
  145.  
  146.      public ArrayList<GoodsInfo> query(String condition) {
  147.          String sql = String.format("select rowid,_id,name,desc,price,thumb_path,pic_path" +
  148.                  " from %s where %s;", TABLE_NAME, condition);
  149.          Log.d(TAG, "query sql: "+sql);
  150.          ArrayList<GoodsInfo> infoArray = new ArrayList<GoodsInfo>();
  151.          Cursor cursor = mDB.rawQuery(sql, null);
  152.          if (cursor.moveToFirst()) {
  153.              for (;; cursor.moveToNext()) {
  154.                  GoodsInfo info = new GoodsInfo();
  155.                  info.rowid = cursor.getLong(0);
  156.                  info.xuhao = cursor.getInt(1);
  157.                  info.name = cursor.getString(2);
  158.                  info.desc = cursor.getString(3);
  159.                  info.price = cursor.getFloat(4);
  160.                  info.thumb_path = cursor.getString(5);
  161.                  info.pic_path = cursor.getString(6);
  162.                  infoArray.add(info);
  163.                  if (cursor.isLast() == true) {
  164.                      break;
  165.                  }
  166.              }
  167.          }
  168.          cursor.close();
  169.          return infoArray;
  170.      }
  171.  
  172.      public GoodsInfo queryById(long rowid) {
  173.          GoodsInfo info = null;
  174.          ArrayList<GoodsInfo> infoArray = query(String.format("rowid='%d'", rowid));
  175.          if (infoArray.size() > 0) {
  176.              info = infoArray.get(0);
  177.          }
  178.          return info;
  179.      }
  180.  
  181.  }
  1.  package com.example.alimjan.hello_world.dataBase;
  2.  
  3.  import android.content.ContentValues;
  4.  import android.content.Context;
  5.  import android.database.Cursor;
  6.  import android.database.sqlite.SQLiteDatabase;
  7.  import android.database.sqlite.SQLiteOpenHelper;
  8.  import android.util.Log;
  9.  
  10.  import com.example.alimjan.hello_world.bean.CartInfo;
  11.  
  12.  import java.util.ArrayList;
  13.  
  14.  public class CartDBHelper extends SQLiteOpenHelper {
  15.      private static final String TAG = "CartDBHelper";
  16.      private static final String DB_NAME = "cart.db";
  17.      private static final int DB_VERSION = 1;
  18.      private static CartDBHelper mHelper = null;
  19.      private SQLiteDatabase mDB = null;
  20.      private static final String TABLE_NAME = "cart_info";
  21.  
  22.      private CartDBHelper(Context context) {
  23.          super(context, DB_NAME, null, DB_VERSION);
  24.      }
  25.  
  26.      private CartDBHelper(Context context, int version) {
  27.          super(context, DB_NAME, null, version);
  28.      }
  29.  
  30.      public static CartDBHelper getInstance(Context context, int version) {
  31.          if (version > 0 && mHelper == null) {
  32.              mHelper = new CartDBHelper(context, version);
  33.          } else if (mHelper == null) {
  34.              mHelper = new CartDBHelper(context);
  35.          }
  36.          return mHelper;
  37.      }
  38.  
  39.      public SQLiteDatabase openReadLink() {
  40.          if (mDB == null || mDB.isOpen() != true) {
  41.              mDB = mHelper.getReadableDatabase();
  42.          }
  43.          return mDB;
  44.      }
  45.  
  46.      public SQLiteDatabase openWriteLink() {
  47.          if (mDB == null || mDB.isOpen() != true) {
  48.              mDB = mHelper.getWritableDatabase();
  49.          }
  50.          return mDB;
  51.      }
  52.  
  53.      public void closeLink() {
  54.          if (mDB != null && mDB.isOpen() == true) {
  55.              mDB.close();
  56.              mDB = null;
  57.          }
  58.      }
  59.  
  60.      public String getDBName() {
  61.          if (mHelper != null) {
  62.              return mHelper.getDatabaseName();
  63.          } else {
  64.              return DB_NAME;
  65.          }
  66.      }
  67.  
  68.      @Override
  69.      public void onCreate(SQLiteDatabase db) {
  70.          Log.d(TAG, "onCreate");
  71.          String drop_sql = "DROP TABLE IF EXISTS " + TABLE_NAME + ";";
  72.          Log.d(TAG, "drop_sql:" + drop_sql);
  73.          db.execSQL(drop_sql);
  74.          String create_sql = "CREATE TABLE IF NOT EXISTS " + TABLE_NAME + " ("
  75.                  + "_id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,"
  76.                  + "goods_id LONG NOT NULL," + "count INTEGER NOT NULL,"
  77.                  + "update_time VARCHAR NOT NULL"
  78.                  + ");";
  79.          Log.d(TAG, "create_sql:" + create_sql);
  80.          db.execSQL(create_sql);
  81.      }
  82.  
  83.      @Override
  84.      public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
  85.      }
  86.  
  87.      public int delete(String condition) {
  88.          int count = mDB.delete(TABLE_NAME, condition, null);
  89.          return count;
  90.      }
  91.  
  92.      public int deleteAll() {
  93.          int count = mDB.delete(TABLE_NAME, "1=1", null);
  94.          return count;
  95.      }
  96.  
  97.      public long insert(CartInfo info) {
  98.          ArrayList<CartInfo> infoArray = new ArrayList<CartInfo>();
  99.          infoArray.add(info);
  100.          return insert(infoArray);
  101.      }
  102.  
  103.      public long insert(ArrayList<CartInfo> infoArray) {
  104.          long result = -1;
  105.          for (int i = 0; i < infoArray.size(); i++) {
  106.              CartInfo info = infoArray.get(i);
  107.              Log.d(TAG, "goods_id="+info.goods_id+", count="+info.count);
  108.              // 如果存在相同rowid的记录，则更新记录
  109.              if (info.rowid > 0) {
  110.                  String condition = String.format("rowid='%d'", info.rowid);
  111.                  update(info, condition);
  112.                  result = info.rowid;
  113.                  continue;
  114.              }
  115.              // 不存在唯一性重复的记录，则插入新记录
  116.              ContentValues cv = new ContentValues();
  117.              cv.put("goods_id", info.goods_id);
  118.              cv.put("count", info.count);
  119.              cv.put("update_time", info.update_time);
  120.              result = mDB.insert(TABLE_NAME, "", cv);
  121.              // 添加成功后返回行号，失败后返回-1
  122.              if (result == -1) {
  123.                  return result;
  124.              }
  125.          }
  126.          return result;
  127.      }
  128.  
  129.      public int update(CartInfo info, String condition) {
  130.          ContentValues cv = new ContentValues();
  131.          cv.put("goods_id", info.goods_id);
  132.          cv.put("count", info.count);
  133.          cv.put("update_time", info.update_time);
  134.          int count = mDB.update(TABLE_NAME, cv, condition, null);
  135.          return count;
  136.      }
  137.  
  138.      public int update(CartInfo info) {
  139.          return update(info, "rowid="+info.rowid);
  140.      }
  141.  
  142.      public ArrayList<CartInfo> query(String condition) {
  143.          String sql = String.format("select rowid,_id,goods_id,count,update_time" +
  144.                  " from %s where %s;", TABLE_NAME, condition);
  145.          Log.d(TAG, "query sql: "+sql);
  146.          ArrayList<CartInfo> infoArray = new ArrayList<CartInfo>();
  147.          Cursor cursor = mDB.rawQuery(sql, null);
  148.          if (cursor.moveToFirst()) {
  149.              for (;; cursor.moveToNext()) {
  150.                  CartInfo info = new CartInfo();
  151.                  info.rowid = cursor.getLong(0);
  152.                  info.xuhao = cursor.getInt(1);
  153.                  info.goods_id = cursor.getLong(2);
  154.                  info.count = cursor.getInt(3);
  155.                  info.update_time = cursor.getString(4);
  156.                  infoArray.add(info);
  157.                  if (cursor.isLast() == true) {
  158.                      break;
  159.                  }
  160.              }
  161.          }
  162.          cursor.close();
  163.          return infoArray;
  164.      }
  165.  
  166.      public CartInfo queryById(long rowid) {
  167.          CartInfo info = null;
  168.          ArrayList<CartInfo> infoArray = query(String.format("rowid='%d'", rowid));
  169.          if (infoArray.size() > 0) {
  170.              info = infoArray.get(0);
  171.          }
  172.          return info;
  173.      }
  174.  
  175.      public CartInfo queryByGoodsId(long goods_id) {
  176.          CartInfo info = null;
  177.          ArrayList<CartInfo> infoArray = query(String.format("goods_id='%d'", goods_id));
  178.          if (infoArray.size() > 0) {
  179.              info = infoArray.get(0);
  180.          }
  181.          return info;
  182.      }
  183.  
  184.  }
  1.  package com.example.alimjan.hello_world.bean;
  2.  
  3.  public class GoodsInfo {
  4.      public long rowid;
  5.      public int xuhao;
  6.      public String name;
  7.      public String desc;
  8.      public float price;
  9.      public String thumb_path;
  10.      public String pic_path;
  11.  
  12.      public GoodsInfo() {
  13.          rowid = 0l;
  14.          xuhao = 0;
  15.          name = "";
  16.          desc = "";
  17.          price = 0;
  18.          thumb_path = "";
  19.          pic_path = "";
  20.      }
  21.  }
  1.  package com.example.alimjan.hello_world.bean;
  2.  
  3.  public class CartInfo {
  4.      public long rowid;
  5.      public int xuhao;
  6.      public long goods_id;
  7.      public int count;
  8.      public String update_time;
  9.  
  10.      public CartInfo() {
  11.          rowid = 0l;
  12.          xuhao = 0;
  13.          goods_id = 0l;
  14.          count = 0;
  15.          update_time = "";
  16.      }
  17.  }
  1. <menu xmlns:android="http://schemas.android.com/apk/res/android" >
  2.  
  3.     <item
  4.         android:id="@+id/menu_shopping"
  5.         android:orderInCategory="1"
  6.         android:title="去商场购物"/>
  7.  
  8.     <item
  9.         android:id="@+id/menu_clear"
  10.         android:orderInCategory="2"
  11.         android:title="清空购物车"/>
  12.  
  13.     <item
  14.         android:id="@+id/menu_return"
  15.         android:orderInCategory="9"
  16.         android:title="返回"/>
  17.  
  18. </menu>
  1. <menu xmlns:android="http://schemas.android.com/apk/res/android" >
  2.  
  3.     <item
  4.         android:id="@+id/menu_detail"
  5.         android:orderInCategory="1"
  6.         android:title="查看商品详情"/>
  7.  
  8.     <item
  9.         android:id="@+id/menu_delete"
  10.         android:orderInCategory="2"
  11.         android:title="从购物车删除"/>
  12.  
  13. </menu>
  1. <?xml version="1.0" encoding="utf-8"?>
  2. <shape xmlns:android="http://schemas.android.com/apk/res/android"
  3.     android:shape="oval" >
  4.  
  5.     <solid android:color="#ff6666" />
  6.  
  7. </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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