zoukankan      html  css  js  c++  java
  • 第10个作业

    package com.example.an4;
    
    import android.content.Context;
    import android.util.Log;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.BaseAdapter;
    import android.widget.TextView;
    
    import java.util.List;
    
    public class CartAdapter extends BaseAdapter {
        private List<CartBean> list;
        private LayoutInflater layoutInflater;
        public CartAdapter(Context context, List<CartBean> list){
            this.layoutInflater = LayoutInflater.from(context);
            this.list = list;
        }
        @Override
        public int getCount() {
            Log.e("yanwenhua","list.size()--"+list.size());
            return list.size();
        }
    
        @Override
        public Object getItem(int position) {
            return null;
        }
    
        @Override
        public long getItemId(int position) {
            return 0;
        }
    
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            ViewHolder viewHolder;
            if (convertView==null){
                convertView=layoutInflater.inflate(R.layout.listview,null);
                viewHolder=new ViewHolder(convertView);
                convertView.setTag(viewHolder);
            }else {
                viewHolder=(ViewHolder) convertView.getTag();
            }
            CartBean cartBean = list.get(position);
            viewHolder.tv_name.setText("商品名称:"+cartBean.getName());
            viewHolder.tv_price.setText("商品价格:"+cartBean.getPrice());
            viewHolder.tv_number.setText("商品数量:"+cartBean.getNumber());
            Log.e("yanwenhua","cartBean.getName()-"+cartBean.getName()+"  "+cartBean.getPrice()+"  "+cartBean.getNumber());
            return convertView;
        }
        class ViewHolder{
            TextView tv_name;
            TextView tv_price;
            TextView tv_number;
            public ViewHolder(View view){
                tv_name = (TextView) view.findViewById(R.id.tv_name);
                tv_price = (TextView) view.findViewById(R.id.tv_price);
                tv_number = (TextView) view.findViewById(R.id.tv_number);
            }
        }
    
    }
    package com.example.an4;
    
    public class CartBean {
        private String name;
        private String price;
        private String number;
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public String getPrice() {
            return price;
        }
    
        public void setPrice(String price) {
            this.price = price;
        }
    
        public String getNumber() {
            return number;
        }
    
        public void setNumber(String number) {
            this.number = number;
        }
    }
    package com.example.an4;
    
    import android.app.Activity;
    import android.content.ContentValues;
    import android.database.Cursor;
    import android.database.sqlite.SQLiteDatabase;
    
    import android.os.Bundle;
    import android.util.Log;
    import android.view.View;
    import android.widget.BaseAdapter;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.ListView;
    import android.widget.Toast;
    
    import java.util.ArrayList;
    import java.util.List;
    
    public class MainActivity extends Activity implements View.OnClickListener {
        private EditText et_name,et_price,et_number;
        private ListView listView;
        private String name,price,number;
        private  MyHelper myHelper;
        private SQLiteDatabase db;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            et_name = (EditText)findViewById(R.id.et_name);
            et_price =  (EditText)findViewById(R.id.et_price);
            et_number =  (EditText) findViewById(R.id.et_number);
            listView = (ListView)findViewById(R.id.listView);
            Button add = (Button)findViewById(R.id.add);
            Button query =(Button) findViewById(R.id.query);
            Button update =(Button) findViewById(R.id.update);
            Button delete = (Button)findViewById(R.id.delete);
            add.setOnClickListener(this);
            query.setOnClickListener(this);
            update.setOnClickListener(this);
            delete.setOnClickListener(this);
            myHelper = new MyHelper(this);
        }
    
        @Override
        public void onClick(View v) {
            switch (v.getId()){
                case R.id.add:
                    db = myHelper.getWritableDatabase();
                    name = et_name.getText().toString();
                    price = et_price.getText().toString();
                    number = et_number.getText().toString();
                    ContentValues values = new ContentValues();        //创建ContentValues对象
                    values.put("name", name);             //将数据添加到ContentValues对象
                    values.put("price", price);
                    values.put("number", number);
                    db.insert("cart", null, values);
                    db.close();
                    Toast.makeText(this, "信息已添加", Toast.LENGTH_SHORT).show();
                    break;
                case R.id.query:
                    Log.e("yanwenhua","123");
                    List<CartBean> list = new ArrayList();
                    db = myHelper.getWritableDatabase();
                    Cursor cursor = db.query("cart", null, null, null, null,
                            null, null);
                    if (cursor.getCount() == 0) {
                        Toast.makeText(this, "没有数据", Toast.LENGTH_SHORT).show();
                    } else {
                        while (cursor.moveToNext()) {
                            CartBean cartBean = new CartBean();
                            int nameIndex = cursor.getColumnIndex("name");
                            int priceIndex = cursor.getColumnIndex("price");
                            int numberIndex = cursor.getColumnIndex("number");
                            String name = cursor.getString(nameIndex);
                            String price = cursor.getString(priceIndex);
                            String number = cursor.getString(numberIndex);
                            Log.e("yanwenhua","cursor.getCount();--"+cursor.getCount()+"name-"+name+"  "+price+"  "+number);
                            cartBean.setName(name);
                            cartBean.setPrice(price);
                            cartBean.setNumber(number);
                            list.add(cartBean);
                        }
                        CartAdapter adapter = new CartAdapter(MainActivity.this,list);
                        listView.setAdapter(adapter);
                        adapter.notifyDataSetChanged();
                    }
                    cursor.close();
                    db.close();
                    break;
                case  R.id.update:
                    name = et_name.getText().toString();
                    price = et_price.getText().toString();
                    number = et_number.getText().toString();
                    db = myHelper.getWritableDatabase();
                    values = new ContentValues();       // 要修改的数据
                    values.put("number",number);
                    values.put("price",price);
                    db.update("cart", values, "name=?",
                            new String[]{name}); // 更新并得到行数
                    db.close();
                    Toast.makeText(this, "信息已修改", Toast.LENGTH_SHORT).show();
                    break;
                case R.id.delete:
                    db = myHelper.getWritableDatabase();
                    db.delete("cart", null, null);
                    List<CartBean> list2 = new ArrayList();
                    CartAdapter adapter = new CartAdapter(MainActivity.this,list2);
                    listView.setAdapter(adapter);
                    adapter.notifyDataSetChanged();
                    db.close();
                    Toast.makeText(this, "信息已删除", Toast.LENGTH_SHORT).show();
                    break;
            }
    
        }
    }
    package com.example.an4;
    
    import android.content.Context;
    import android.database.sqlite.SQLiteDatabase;
    import android.database.sqlite.SQLiteOpenHelper;
    
    class MyHelper extends SQLiteOpenHelper {
        public MyHelper(Context context) {
            super(context, "shoppingcart.db", null, 1);
        }
        @Override
        public void onCreate(SQLiteDatabase db) {
            db.execSQL("CREATE TABLE cart(_id INTEGER PRIMARY KEY AUTOINCREMENT, name VARCHAR(20),  price VARCHAR(20), number VARCHAR(20))");
        }
        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        }
    }
    <?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"
        android:background="#E6E6E6"
        android:orientation="vertical"
        android:padding="10dp">
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="15dp"
            android:background="@android:color/white"
            android:orientation="horizontal">
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:padding="10dp"
                android:text="名称:"
                android:textColor="#000"
                android:textSize="20sp" />
            <EditText
                android:id="@+id/et_name"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginLeft="5dp"
                android:background="@null"
                android:padding="10dp"
                android:maxLines="1"/>
        </LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="15dp"
            android:background="@android:color/white"
            android:orientation="horizontal">
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:padding="10dp"
                android:text="价格:"
                android:textColor="#000"
                android:textSize="20sp" />
            <EditText
                android:id="@+id/et_price"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginLeft="5dp"
                android:background="@null"
                android:padding="10dp"
                android:maxLines="1"/>
        </LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:background="@android:color/white"
            android:orientation="horizontal">
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:padding="10dp"
                android:text="数量:"
                android:textColor="#000"
                android:textSize="20sp" />
            <EditText
                android:id="@+id/et_number"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginLeft="5dp"
                android:background="@null"
                android:padding="10dp"
                android:maxLines="1"/>
        </LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:layout_marginTop="10dp">
            <Button
                android:id="@+id/add"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="添加"/>
            <Button
                android:id="@+id/query"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="查询"/>
            <Button
                android:id="@+id/update"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="修改"/>
            <Button
                android:id="@+id/delete"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="删除"/>
        </LinearLayout>
        <ListView
            android:id="@+id/listView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="#ffffff">
        </ListView>
    </LinearLayout>
    <?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"
        android:orientation="vertical"
        android:padding="10dp">
        <TextView
            android:id="@+id/tv_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="15sp"/>
        <TextView
            android:id="@+id/tv_price"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="3dp"
            android:textSize="15sp"/>
        <TextView
            android:id="@+id/tv_number"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="3dp"
            android:textSize="15sp"/>
    
    </LinearLayout>
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  • 原文地址:https://www.cnblogs.com/Suzy-an/p/11846629.html
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