ListView和SQLite数据库案例--商品展示

。在商品展示案例中我们可以在界面中对商品进行增、删、改、查。要实现这些功能需要使用ListView 和 SQLine数据库。

1、运行效果图

2、实现过程

activity_main.xml，如图

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:id="@+id/activity_main"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context="cn.edu.bzu.test02.MainActivity">    <LinearLayout        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:orientation="horizontal">        <EditText            android:id="@+id/nameET"            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:layout_weight="1"            android:hint="商品名称"/>        <EditText            android:id="@+id/balanceET"            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:layout_weight="1"            android:hint="金额"/>        <ImageView            android:id="@+id/add"            android:layout_width="wrap_content"            android:layout_height="25dp"            android:layout_weight="1"            android:onClick="add"            android:src="@drawable/add"/>    </LinearLayout>    <ListView        android:id="@+id/listView"        android:layout_width="match_parent"        android:layout_height="match_parent"        android:layout_marginTop="30dp">    </ListView></RelativeLayout>

ListView布局文件：item.xml，如图

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:orientation="horizontal">    <TextView        android:id="@+id/idTV"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_weight="1"        android:text="13"        android:textColor="#000000"        android:textSize="20sp"/>    <TextView        android:id="@+id/nameTV"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_weight="2"        android:text="PQ"        android:textColor="#000000"/>    <TextView        android:id="@+id/balanceTV"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_weight="1"        android:text="12345"        android:textColor="#000000"/>    <LinearLayout        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:orientation="vertical">        <ImageView            android:id="@+id/upIV"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:src="@android:drawable/arrow_up_float"/>        <ImageView            android:id="@+id/downIV"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:src="@android:drawable/arrow_down_float"/>    </LinearLayout>    <ImageView        android:id="@+id/deleteIV"        android:layout_width="25dp"        android:layout_height="25dp"        android:src="@android:drawable/ic_menu_delete"/></LinearLayout>

创建数据库：DBHelper.xml

package cn.edu.bzu.test02.db;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;import android.provider.Settings;public class DBHelper extends SQLiteOpenHelper {    private Context context;    public static final String DB_NAME = "GoodsStore.db";    public static final String CREATE_GOODS = "create table goods(id integer primary key autoincrement,name varchar(20),balance integer)";//商品名称列和金额列    public DBHelper(Context context) {        super(context, DB_NAME, null, 2);    }    @Override    public void onCreate(SQLiteDatabase db) {        System.out.println("create succeed");        db.execSQL(CREATE_GOODS);    }    @Override    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {        System.out.println("onUpgrade succeed");    }}

Goods类：Goods.java

public class Goods {    private long id;    private String name;    private Integer balance;    public Long getId() {        return id;    }    public void setId(Long id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public Integer getBalance() {        return balance;    }    public void setBalance(Integer balance) {        this.balance = balance;    }    public Goods(Long id, String name, Integer balance) {        super();        this.id=id;        this.balance = balance;        this.name = name;    }    public Goods(String name,Integer balance){        super();        this.name=name;        this.balance=balance;    }    public Goods(){        super();    }    public String toString() {        return "名称" + name + "价格" + balance;    }}

GoodsDao.java，用于操作数据

package cn.edu.bzu.test02.dao;import android.content.ContentValues;import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import java.util.ArrayList;import java.util.List;import cn.edu.bzu.test02.bean.Goods;import cn.edu.bzu.test02.db.DBHelper;public class GoodsDao {    private DBHelper helper;    public GoodsDao(Context context) {       //创建Dao时，创建Helper        helper = new DBHelper(context);    }    public void insert(Goods goods) {       //获取数据库对象        SQLiteDatabase db = helper.getWritableDatabase();        ContentValues values = new ContentValues();        values.put("name", goods.getName());        values.put("balance", goods.getBalance());        long id = db.insert("goods", null, values);        goods.setId(id);        db.close();//关闭数据库    }    //根据id删除数据    public int detele(long id) {        SQLiteDatabase db = helper.getWritableDatabase();        int count = db.delete("goods", "id=?", new String[]{id + ""});        db.close();        return count;    }   //更新数据    public int update(Goods goods) {        SQLiteDatabase DB = helper.getWritableDatabase();        ContentValues values = new ContentValues();        values.put("name", goods.getName());        values.put("balance", goods.getBalance());        int count = DB.update("goods", values, "id=?", new String[]{goods.getId() + ""});        DB.close();        return count;    }  //查询所有数据倒序排列    public List<Goods> queryAll() {        SQLiteDatabase db = helper.getReadableDatabase();        Cursor curor = db.query("goods", null, null, null, null, null, "balance DESC");        List<Goods> list = new ArrayList<Goods>();        while (curor.moveToNext()) {            long id = curor.getLong(curor.getColumnIndex("id"));            String name = curor.getString(1);            int balance = curor.getInt(2);            list.add(new Goods(id, name, balance));        }        db.close();        curor.close();        return list;    }}

界面交互：MainActivity.java

package cn.edu.bzu.test02;import android.app.Activity;import android.content.DialogInterface;import android.support.v7.app.AlertDialog;import android.os.Bundle;import android.view.View;import android.view.ViewGroup;import android.widget.AdapterView;import android.widget.BaseAdapter;import android.widget.ArrayAdapter;import android.widget.EditText;import android.widget.ImageView;import android.widget.ListView;import android.widget.TextView;import android.widget.Toast;import java.util.List;import cn.edu.bzu.test02.bean.Goods;import cn.edu.bzu.test02.dao.GoodsDao;public class MainActivity extends Activity {    private ListView goodsLV;    private GoodsDao goodsdao;    private EditText nameET;    private EditText balanceET;    private MyAdapter adapter;    private List<Goods> list;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initView();        goodsdao = new GoodsDao(this);        list = goodsdao.queryAll();        adapter = new MyAdapter();        goodsLV.setAdapter(adapter);    }   //初始化控件    private void initView() {        goodsLV = (ListView) findViewById(R.id.listView);        nameET = (EditText) findViewById(R.id.nameET);        balanceET = (EditText) findViewById(R.id.balanceET);        goodsLV.setOnItemClickListener(new MyOnItemClickListener());    }   //点击事件触发    public void add(View view) {        String name = nameET.getText().toString().trim();        String balance = balanceET.getText().toString().trim();        Goods goods = new Goods(name, balance.equals("") ? 0 : Integer.parseInt(balance));        goodsdao.insert(goods);        list.add(goods);        adapter.notifyDataSetChanged();        goodsLV.setSelection(goodsLV.getCount() - 1);        nameET.setText("");        balanceET.setText("");    }    /自定义一个适配器    private class MyAdapter extends BaseAdapter {        @Override        public int getCount() {            return list.size();        }        @Override        public Object getItem(int position) {            return list.get(position);        }        @Override        public long getItemId(int position) {            return position;        }        @Override        public View getView(int position, View convertView, ViewGroup parent) {            View item = convertView != null ? convertView : View.inflate(getApplicationContext(), R.layout.item, null);            TextView idTV = (TextView) item.findViewById(R.id.idTV);            TextView nameTV = (TextView) item.findViewById(R.id.nameTV);            TextView balanceTV = (TextView) item.findViewById(R.id.balanceTV);            final Goods g = list.get(position);            idTV.setText(g.getId() + "");            nameTV.setText(g.getName());            balanceTV.setText(g.getBalance() + "");            ImageView upIV = (ImageView) item.findViewById(R.id.upIV);            ImageView downIV = (ImageView) item.findViewById(R.id.downIV);            ImageView deleteIV = (ImageView) item.findViewById(R.id.deleteIV);            //向上箭头的点击事件            upIV.setOnClickListener(new View.OnClickListener() {                @Override                public void onClick(View view) {                    g.setBalance(g.getBalance() + 1);                    notifyDataSetChanged();                    goodsdao.update(g);                }            });            //向下箭头的点击事件            downIV.setOnClickListener(new View.OnClickListener() {                @Override                public void onClick(View view) {                    g.setBalance(g.getBalance() - 1);                    notifyDataSetChanged();                    goodsdao.update(g);                }            });            //删除图片的点击事件            deleteIV.setOnClickListener(new View.OnClickListener() {                @Override                public void onClick(View view) {                    android.content.DialogInterface.OnClickListener listener = new android.content.DialogInterface.OnClickListener() {                        @Override                        public void onClick(DialogInterface dialogInterface, int i) {                            list.remove(g);                            goodsdao.detele(g.getId());                            notifyDataSetChanged();                        }                    };                    //创建对话框                    AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);                    builder.setTitle("确定要删除吗？");                    builder.setPositiveButton("确定", listener);                    builder.setNegativeButton("取消", null);                    builder.show();                }            });            return item;        }    }  //ListView的点击事件    private class MyOnItemClickListener implements AdapterView.OnItemClickListener {        @Override        public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {            Goods goods = (Goods) adapterView.getItemAtPosition(i);            Toast.makeText(getApplicationContext(), goods.toString(), Toast.LENGTH_SHORT).show();        }    }}

3、清单文件：

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="cn.edu.bzu.test02">    <application        android:allowBackup="true"        android:icon="@mipmap/ic_launcher"        android:label="@string/app_name"        android:supportsRtl="true"        android:theme="@style/AppTheme">        <activity android:name=".MainActivity">            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>    </application></manifest>

4、使用
输入数据点击添加按钮会出现，如图

点击删除会删除相应的商品，会弹出一个对话框

点击向上箭头和向下箭头会会对金额进行加减的操作，并且点击条目会出现一个Toast