安卓商品展示
1.编写界面布局
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">
android:layout_height="wrap_content"
android:orientation="horizontal">
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:hint="商品名称"
android:inputType="text"
android:layout_weight="1"
/>
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:hint="商品数量"
android:inputType="number"
android:layout_weight="1"/>
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="add"
android:src="@android:drawable/ic_input_add"/>
android:layout_width="match_parent"
android:layout_height="match_parent">
2.编写每一项的布局
android:layout_height="match_parent">
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/tv_id"
android:textSize="20dp"
android:layout_weight="1" />
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/tv_name"
android:layout_weight="1"
android:textSize="20dp"/>
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/tv_number"
android:layout_weight="1"
android:textSize="20dp"/>
android:layout_height="wrap_content"
android:orientation="vertical">
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@android:drawable/arrow_up_float"/>
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@android:drawable/arrow_down_float"/>
android:layout_width="25dp"
android:layout_height="25dp"
android:src="@android:drawable/ic_menu_delete"/>
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
private int resounceId;
private GoodsDao goodsDao;
private List
public GoodsAdapter(Context context, int resource, List
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
List
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
@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
