1.编写界面布局
<?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.administrator.xzx.MainActivity">
<LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal">
<EditText android:id="@+id/et_name" android:layout_width="wrap_content" android:layout_height="wrap_content" android:hint="商品名称" android:inputType="text" android:layout_weight="1" /> <EditText android:id="@+id/et_number" android:layout_width="wrap_content" android:layout_height="wrap_content" android:hint="商品数量" android:inputType="number" android:layout_weight="1"/> <ImageView android:id="@+id/et_button" android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="add" android:src="@android:drawable/ic_input_add"/> </LinearLayout>
<ListView android:id="@+id/lvGoods" android:layout_width="match_parent" android:layout_height="match_parent">
</ListView> </LinearLayout>
2.编写每一项的布局
<?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:text="1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/tv_id" android:textSize="20dp" android:layout_weight="1" /> <TextView android:text="商品名称" android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/tv_name" android:layout_weight="1" android:textSize="20dp"/>
<TextView android:text="商品数量" android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/tv_number" android:layout_weight="1" android:textSize="20dp"/>
<LinearLayout android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="vertical"> <ImageView android:id="@+id/tv_up" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@android:drawable/arrow_up_float"/> <ImageView android:id="@+id/tv_down" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@android:drawable/arrow_down_float"/>
</LinearLayout> <ImageView android:id="@+id/tv_delet" android:layout_width="25dp" android:layout_height="25dp"
android:src="@android:drawable/ic_menu_delete"/> </LinearLayout>
3.编写商品类 包含商品的id number和商品的名称
package com.example.administrator.xzx.entity;
/** * Created by Administrator on 2017/3/30. */
public class Goods { private long id; private String name; private int number;
public Goods(long id, String name, int number) { this.id = id; this.name = name; this.number = number; }
public Goods(String name, int number) { this.name = name; this.number = number; }
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 getNumber() { return number; }
public void setNumber(int number) { this.number = number; }
@Override public String toString() { return "Goods{" + "id=" + id + ", name='" + name + '\'' + ", number=" + number + '}'; } }
4.创建适配器GoodsAdapter类
package com.example.administrator.xzx; import android.content.Context; import android.content.DialogInterface; 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.administrator.xzx.dao.GoodsDao; import com.example.administrator.xzx.entity.Goods;
import java.util.List;
/** * Created by Administrator on 2017/3/30. */
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); View view=null; ViewHolder viewHolder; if(convertView==null){ view= LayoutInflater.from(getContext()).inflate(R.layout.item,null); viewHolder=new ViewHolder(); viewHolder.tvid=(TextView)view.findViewById(R.id.tv_id); viewHolder.tvname=(TextView)view.findViewById((R.id.tv_name)); viewHolder.tvnumber=(TextView)view.findViewById(R.id.tv_number); viewHolder.ivup=(ImageView)view.findViewById(R.id.tv_up); viewHolder.ivdown=(ImageView)view.findViewById(R.id.tv_down); viewHolder.ivdelet=(ImageView)view.findViewById(R.id.tv_delet); view.setTag(viewHolder); }else{ view=convertView; viewHolder=(ViewHolder)view.getTag(); } viewHolder.tvid.setText(goods.getId()+""); viewHolder.tvname.setText(goods.getName()); viewHolder.tvnumber.setText(goods.getNumber()+""); viewHolder.ivdelet.setOnClickListener(new View.OnClickListener() { @Override 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 dialog, int which) { goodsList.remove(goods); goodsDao.delete(goods.getId()); notifyDataSetChanged(); } }); builder.setNegativeButton("cancel",null); builder.show(); } }); viewHolder.ivup.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { goods.setNumber(goods.getNumber()-1); goodsDao.update(goods); notifyDataSetChanged(); } }); viewHolder.ivdown.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { goods.setNumber(goods.getNumber()+1); goodsDao.update(goods); notifyDataSetChanged(); } }); return view; }
class ViewHolder { TextView tvid; TextView tvname; TextView tvnumber; ImageView ivup; ImageView ivdown; ImageView ivdelet;
} }
5.进行数据库操作
创建JAVA类DBHelper
package com.example.administrator.xzx.db;
import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper;
/** * Created by Administrator on 2017/3/30. */
public class DBHelper extends SQLiteOpenHelper { public static final String CREATE_GOODS = "create table goods(_id integer primary key autoincrement,name varchar(20),number 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 db, int oldVersion, int newVersion) {
} }
6.创建goodsDao用作商品增删改查
package com.example.administrator.xzx.dao; import android.content.ContentValues; import android.content.Context; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper;
import com.example.administrator.xzx.db.DBHelper; import com.example.administrator.xzx.entity.Goods;
import java.util.ArrayList; import java.util.Deque; import java.util.List;
/** * Created by Administrator on 2017/3/30. */
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("number",goods.getNumber()); 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("number",goods.getNumber()); 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,"number desc"); while(cursor.moveToNext()){ long id=cursor.getLong(cursor.getColumnIndex("_id")); String name=cursor.getString(cursor.getColumnIndex("name")); int number=cursor.getInt(cursor.getColumnIndex("number")); Goods goods=new Goods(id,name,number); goodsList.add(goods); } cursor.close(); sqLiteDatabase.close(); return goodsList; } }
7.MainActivity 添加商品
package com.example.administrator.xzx;
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.administrator.xzx.dao.GoodsDao; import com.example.administrator.xzx.entity.Goods;
import java.util.List;
public class MainActivity extends AppCompatActivity { private EditText etName; private EditText etNumber; private ListView lvGoods; private GoodsAdapter goodsAdapter; private GoodsDao goodsDao; private List<Goods> goodsList;
@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); etName = (EditText) findViewById(R.id.et_name); etNumber = (EditText) findViewById(R.id.et_number); 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 add(View view) { String name = etName.getText().toString(); String number = etNumber.getText().toString(); if(TextUtils.isEmpty(name)||TextUtils.isEmpty(number)) return; Goods goods = new Goods(name, number.equals("") ? 0 : Integer.parseInt(number)); goodsDao.add(goods); goodsList.add(goods); goodsAdapter.notifyDataSetChanged(); etName.setText(""); etNumber.setText(""); Toast.makeText(this,"添加成功",Toast.LENGTH_LONG).show();
} }
8.运行测试结果
