商品展示案例

总布局界面

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

<LinearLayout 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:orientation="vertical"

    tools:context="com.example.bz0209.myapplication.MainActivity">

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="wrap_content">

        <EditText

            android:id="@+id/etName"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:layout_weight="1"

            android:hint="商品名称"

            android:inputType="text" />

        <EditText

            android:id="@+id/etNumber"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:layout_weight="1"

            android:hint="商品数量"

            android:inputType="number" />

        <ImageView

            android:id="@+id/ivAdd"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:onClick="addGoods"

            android:src="@android:drawable/ic_input_add" />

    </LinearLayout>

    <ListView

        android:id="@+id/lvGoods"

        android:layout_width="match_parent"

        android:layout_height="match_parent" />

</LinearLayout>

***********************************************************

分布局界面

<?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="match_parent">

    <TextView

        android:id="@+id/tvId"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_weight="1"

        android:text="1"

        android:textSize="20sp" />

    <TextView

        android:id="@+id/tvName"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_weight="2"

        android:text="商品名称"

        android:textSize="20sp" />

    <TextView

        android:id="@+id/tvAmount"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_weight="2"

        android:text="商品数量"

        android:textSize="20sp" />

    <LinearLayout

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:orientation="vertical">

        <ImageView

            android:id="@+id/ivUp"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:src="@android:drawable/arrow_up_float" />

        <ImageView

            android:id="@+id/ivDown"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:src="@android:drawable/arrow_down_float" />

    </LinearLayout>

    <ImageView

        android:id="@+id/ivDelete"

        android:layout_width="25dp"

        android:layout_height="25dp"

        android:src="@android:drawable/ic_menu_delete" />

</LinearLayout>

**************************************************************

创建数据库

package com.example.bz0209.myapplication.db;

import android.content.Context;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteOpenHelper;

/**

 * Created by Administrator on 2017/4/28.

 */

public class DBHelper extends SQLiteOpenHelper {

    private static final String CREATE_GOODS="create table goods(_id integer primary autoincrement ,name varchar(20),amount integer)";

    public DBHelper(Context context, int version) {

        super(context,"goods.db",null, version);

    }

    @Override

    public void onCreate(SQLiteDatabase db) {

        db.execSQL(CREATE_GOODS);

    }

    @Override

    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {

    }

}

*******************************************************************

商品类

package com.example.bz0209.shop.entity;

/**

 * Created by Administrator on 2017/5/4.

 */

public class Goods {

    private long id;

    private String name;

    private int amount;

    public Goods(long id,String name,int amount){

        super();

        this.id=id;

        this.name=name;

        this.amount=amount;

    }

    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 int getAmount() {

        return amount;

    }

    public void setAmount(int amount) {

        this.amount = amount;

    }

    public Goods(String name,int amount){

        super();

        this.name=name;

        this.amount=amount;

    }

    public Goods(){

        super();

    }

    public String toString(){

        return "[序号:"+id+",商品名称:"+name+",余额:"+amount+"]";

    }

}

************************************************************

创建数据库库逻辑类

package com.example.bz0209.myapplication.dao;

import android.content.ContentValues;

import android.content.Context;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

import com.example.bz0209.myapplication.db.DBHelper;

import com.example.bz0209.myapplication.entity.Goods;

import java.sql.SQLData;

import java.util.ArrayList;

import java.util.List;

/**

 * Created by Administrator on 2017/5/4.

 */

public class GoodsDao {

    private DBHelper dbHelper;

    public GoodsDao(Context context){

        dbHelper=new DBHelper(context,1);

    }

    public void add(Goods goods){

        SQLiteDatabase sqLiteDatabase=dbHelper.getWritableDatabase();

        ContentValues values=new ContentValues();

        values.put("name",goods.getName());

        values.put("amount",goods.getAmount());

        long id=sqLiteDatabase.insert("goods",null,values);

        goods.setId(id);

        sqLiteDatabase.close();

    }

    public int delete(long id){

        SQLiteDatabase sqLiteDatabase=dbHelper.getWritableDatabase();

        int count=sqLiteDatabase.delete("goods","_id=?",new String[]{id+""});

        sqLiteDatabase.close();

        return count;

    }

    public int update(Goods goods){

        SQLiteDatabase sqLiteDatabase=dbHelper.getWritableDatabase();

        ContentValues values=new ContentValues();

        values.put("name",goods.getName());

        values.put("amount",goods.getAmount());

        int count=sqLiteDatabase.update("goods",values,"_id=?",new String[]{goods.getId()+""});

        sqLiteDatabase.close();

        return count;

    }

    public List<Goods> queryAll(){

        List<Goods> goodsList=new ArrayList<>();

        SQLiteDatabase sqLiteDatabase=dbHelper.getReadableDatabase();

        Cursor cursor=sqLiteDatabase.query("goods",null,null,null,null,null,"amount desc");

        while(cursor.moveToNext()){

            long id=cursor.getLong(cursor.getColumnIndex("_id"));

            String name=cursor.getString(cursor.getColumnIndex("name"));

            int amount=cursor.getInt(cursor.getColumnIndex("amount"));

            Goods goods=new Goods(id,name,amount);

            goodsList.add(goods);

        }

        cursor.close();

        sqLiteDatabase.close();

        return goodsList;

    }

}

******************************************************************************************

交互界面

package com.example.bz0209.myapplication;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.text.TextUtils;

import android.view.View;

import android.widget.EditText;

import android.widget.ListView;

import android.widget.Toast;

import com.example.bz0209.myapplication.dao.GoodsDao;

import com.exam
b32e
ple.bz0209.myapplication.entity.Goods;

import com.example.bz0209.myapplication.entity.GoodsAdapter;

import java.util.List;

public class MainActivity extends AppCompatActivity {

    private EditText etName;

    private EditText etAmount;

    private GoodsDao goodsDao;

    private ListView lvGoods;

    private GoodsAdapter goodsAdapter;

    private List<Goods> goodsList;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        etName=(EditText)findViewById(R.id.etName);

        etAmount=(EditText)findViewById(R.id.etAmount);

        lvGoods=(ListView)findViewById(R.id.lvGoods);

        goodsDao=new GoodsDao(this);

        goodsList=goodsDao.queryAll();

        goodsAdapter=new GoodsAdapter(this,R.layout.item,goodsList,goodsDao);

        lvGoods.setAdapter(goodsAdapter);

    }

    public void addGoods(View view){

        String name=etName.getText().toString();

        String amount=etAmount.getText().toString();

        if(TextUtils.isEmpty(name)||TextUtils.isEmpty(amount))

            return;

        Goods goods=new Goods(name,Integer.parseInt(amount));

        goodsDao.add(goods);

        goodsList.add(goods);

        goodsAdapter.notifyDataSetChanged();

        etName.setText("");

        etAmount.setText("");

        Toast.makeText(this,"添加成功",Toast.LENGTH_LONG).show();

    }

}

*********************************************************************************

适配器

package com.example.bz0209.myapplication.entity;

import android.content.Context;

import android.content.DialogInterface;

import android.preference.DialogPreference;

import android.support.annotation.NonNull;

import android.support.v7.app.AlertDialog;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.ArrayAdapter;

import android.widget.ImageView;

import android.widget.TextView;

import com.example.bz0209.myapplication.R;

import com.example.bz0209.myapplication.dao.GoodsDao;

import java.util.List;

/**

 * Created by Administrator on 2017/5/5.

 */

public class GoodsAdapter extends ArrayAdapter<Goods> {

    private int resounceId;

    private GoodsDao goodsDao;

    private List<Goods> goodsList;

    public GoodsAdapter(Context context, int resource, List<Goods> objects,GoodsDao goodsDao) {

        super(context, resource, objects);

        resounceId = resource;

        goodsList=objects;

        this.goodsDao=goodsDao;

    }

    @NonNull

    @Override

    public View getView(int position, View convertView, ViewGroup parent) {

        final Goods goods = getItem(position);

        ViewHolder viewHolder;

        View view =null;

        if(convertView==null){

            view= LayoutInflater.from(getContext()).inflate(resounceId,null);

            viewHolder=new ViewHolder();

            viewHolder.tvId= (TextView)view.findViewById(R.id.tvId);

            viewHolder.tvName=(TextView) view.findViewById(R.id.tvName);

            viewHolder. tvAmount = (TextView) view.findViewById(R.id.tvAmount);

            viewHolder.ivUp = (ImageView) view.findViewById(R.id.ivUp);

            viewHolder.ivDown = (ImageView) view.findViewById(R.id.ivDown);

            viewHolder.ivDelete = (ImageView) view.findViewById(R.id.ivDelete);

            view.setTag(viewHolder);

        }else{

            view=convertView;

            viewHolder=(ViewHolder)view.getTag();

        }

        viewHolder.tvId.setText(goods.getId()+"");

        viewHolder.tvName.setText(goods.getName()+"");

        viewHolder.tvAmount.setText(goods.getAmount()+"");

        viewHolder.ivDelete.setOnClickListener(new View.OnClickListener(){

            public void onClick(View v){

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

                builder.setTitle("你确定要删除吗？");

                builder.setPositiveButton("yes", new DialogInterface.OnClickListener() {

                    @Override

                    public void onClick(DialogInterface dialogInterface, int i) {

                        goodsDao.delete(goods.getId());

                        goodsList.remove(goods);

                        notifyDataSetChanged();

                    }

                });

                builder.setNegativeButton("cancel",null);

                builder.show();

            }

        });

        viewHolder.ivUp.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                goods.setAmount(goods.getAmount()-1);

                goodsDao.update(goods);

                notifyDataSetChanged();

            }

        });

        viewHolder.ivDown.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                goods.setAmount(goods.getAmount()+1);

                goodsDao.update(goods);

                notifyDataSetChanged();

            }

        });

        return view;

    }

    class ViewHolder{

        TextView tvId;

        TextView tvName;

        TextView tvAmount;

        ImageView ivUp;

        ImageView ivDown;

        ImageView ivDelete;

    }

}