第十周作业

购物车

package com.example.myapplication;
 
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
 
import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
 
import java.util.ArrayList;
import java.util.List;
 
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
 
    Intent intent = new Intent();
    EditText name,price,number;
    Button add;
    ListView lv;
    private MyHelper helper;
    List<Sqldata> list = new ArrayList<>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        name = (EditText)findViewById(R.id.et_1);
        price = (EditText)findViewById(R.id.et_2);
        number = (EditText)findViewById(R.id.et_3);
 
        add = (Button)findViewById(R.id.add);
 
        lv = (ListView)findViewById(R.id.list);
 
        helper = new MyHelper(this);
 
 
 
 
    }
 
 
    public void add_Click(View view){
        Sqldata date = new Sqldata(name.getText().toString(),price.getText().toString(),number.getText().toString());
        insert(date);
        Toast.makeText(MainActivity.this,name.getText().toString()+"已添加到购物车",Toast.LENGTH_SHORT).show();
    }
 
    public void delete_Click(View view){
        int num = delete(name.getText().toString());
        if (num > 0){
            Toast.makeText(MainActivity.this,"删除成功",Toast.LENGTH_SHORT).show();
        }else{
            Toast.makeText(MainActivity.this,"删除失败",Toast.LENGTH_SHORT).show();
        }
    }
 
 
 
 
    public void update_Click(View view){
        update(name.getText().toString(),price.getText().toString(),number.getText().toString());
    }
 
 
 
    public void find_Click(View view){
        find(name.getText().toString());
 
    }
 
 
 
    @Override
    public void onClick(View v) {
 
    }
 
 
 
 
    //添加到购物车
 
    public long insert(Sqldata sqldata){
        long id = 0;
        SQLiteDatabase db =null;
 
        try {
            db = helper.getWritableDatabase();
 
            ContentValues values = new ContentValues();
 
            values.put("name",sqldata.getName());
            values.put("price",sqldata.getPrice());
            values.put("number",sqldata.getNumber());
 
            db.insert("car",null,values);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (db != null){
                db.close();
            }
        }
 
 
        return id;
    }
 
    //从购物车中删除
 
    public int delete(String name){
 
        SQLiteDatabase db = null;
        int num = 0;
        try {
            db = helper.getWritableDatabase();
            num = db.delete("car","name = ?",new String[]{name});
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (db!=null){
                db.close();
            }
        }
        return num;
    }
 
    //查看购物车
 
    public List<Sqldata> find(String name){
        SQLiteDatabase db = null;
        db = helper.getReadableDatabase();
        MyBaseAdapter myBaseAdapter = new MyBaseAdapter(this,R.layout.item,list);
        try {
 
                Cursor cursor = db.query("car",null,null,null,null,null,null);
                if (cursor.getCount()!=0){
                    while (cursor.moveToNext()){
                        Sqldata find = new Sqldata();
                        find.setName(cursor.getString(cursor.getColumnIndex("name")));
                        find.setPrice(cursor.getString(cursor.getColumnIndex("price")));
                        find.setNumber(cursor.getString(cursor.getColumnIndex("number")));
                        list.add(find);
                        lv.setAdapter(myBaseAdapter);
                    }
                }
                cursor.close();
 
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (db != null){
                db.close();
            }
        }
 
        return list;
 
    }
 
 
    //对购物车进行修改
 
    public int update(String name,String price,String number){
        SQLiteDatabase db = null;
        int num = 0;
        try {
            db = helper.getWritableDatabase();
            ContentValues values = new ContentValues();
            values.put("price",price);
            values.put("number",number);
            num = db.update("car",values,"name = ?",new String[]{name});
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (db!=null){
                db.close();
            }
        }
 
        return num;
    }
 
 
 
 
 
 
 
    class MyBaseAdapter extends BaseAdapter {
 
        public MyBaseAdapter(MainActivity mainActivity, int list_item, List<Sqldata> show) {
        }
 
        @Override
        public int getCount() {
            return list.size();
        }
 
        @Override
        public Object getItem(int position) {
            return null;
        }
 
        @Override
        public long getItemId(int position) {
            return position;
        }
 
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            View view = View.inflate(MainActivity.this,R.layout.item,null);
            TextView tname = (TextView)view.findViewById(R.id.t_name);
            TextView tprice = (TextView)view.findViewById(R.id.t_price);
            TextView tnumber = (TextView)view.findViewById(R.id.t_number);
 
 
            tname.setText(list.get(position).getName());
            tprice.setText(list.get(position).getPrice());
            tnumber.setText(list.get(position).getNumber());
            return view;
        }
    }
 
 
}package com.example.myapplication;
 
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
 
import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
 
import java.util.ArrayList;
import java.util.List;
 
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
 
    Intent intent = new Intent();
    EditText name,price,number;
    Button add;
    ListView lv;
    private MyHelper helper;
    List<Sqldata> list = new ArrayList<>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        name = (EditText)findViewById(R.id.et_1);
        price = (EditText)findViewById(R.id.et_2);
        number = (EditText)findViewById(R.id.et_3);
 
        add = (Button)findViewById(R.id.add);
 
        lv = (ListView)findViewById(R.id.list);
 
        helper = new MyHelper(this);
 
 
 
 
    }
 
 
    public void add_Click(View view){
        Sqldata date = new Sqldata(name.getText().toString(),price.getText().toString(),number.getText().toString());
        insert(date);
        Toast.makeText(MainActivity.this,name.getText().toString()+"已添加到购物车",Toast.LENGTH_SHORT).show();
    }
 
    public void delete_Click(View view){
        int num = delete(name.getText().toString());
        if (num > 0){
            Toast.makeText(MainActivity.this,"删除成功",Toast.LENGTH_SHORT).show();
        }else{
            Toast.makeText(MainActivity.this,"删除失败",Toast.LENGTH_SHORT).show();
        }
    }
 
 
 
 
    public void update_Click(View view){
        update(name.getText().toString(),price.getText().toString(),number.getText().toString());
    }
 
 
 
    public void find_Click(View view){
        find(name.getText().toString());
 
    }
 
 
 
    @Override
    public void onClick(View v) {
 
    }
 
 
 
 
    //添加到购物车
 
    public long insert(Sqldata sqldata){
        long id = 0;
        SQLiteDatabase db =null;
 
        try {
            db = helper.getWritableDatabase();
 
            ContentValues values = new ContentValues();
 
            values.put("name",sqldata.getName());
            values.put("price",sqldata.getPrice());
            values.put("number",sqldata.getNumber());
 
            db.insert("car",null,values);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (db != null){
                db.close();
            }
        }
 
 
        return id;
    }
 
    //从购物车中删除
 
    public int delete(String name){
 
        SQLiteDatabase db = null;
        int num = 0;
        try {
            db = helper.getWritableDatabase();
            num = db.delete("car","name = ?",new String[]{name});
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (db!=null){
                db.close();
            }
        }
        return num;
    }
 
    //查看购物车
 
    public List<Sqldata> find(String name){
        SQLiteDatabase db = null;
        db = helper.getReadableDatabase();
        MyBaseAdapter myBaseAdapter = new MyBaseAdapter(this,R.layout.item,list);
        try {
 
                Cursor cursor = db.query("car",null,null,null,null,null,null);
                if (cursor.getCount()!=0){
                    while (cursor.moveToNext()){
                        Sqldata find = new Sqldata();
                        find.setName(cursor.getString(cursor.getColumnIndex("name")));
                        find.setPrice(cursor.getString(cursor.getColumnIndex("price")));
                        find.setNumber(cursor.getString(cursor.getColumnIndex("number")));
                        list.add(find);
                        lv.setAdapter(myBaseAdapter);
                    }
                }
                cursor.close();
 
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (db != null){
                db.close();
            }
        }
 
        return list;
 
    }
 
 
    //对购物车进行修改
 
    public int update(String name,String price,String number){
        SQLiteDatabase db = null;
        int num = 0;
        try {
            db = helper.getWritableDatabase();
            ContentValues values = new ContentValues();
            values.put("price",price);
            values.put("number",number);
            num = db.update("car",values,"name = ?",new String[]{name});
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (db!=null){
                db.close();
            }
        }
 
        return num;
    }
 
 
 
 
 
 
 
    class MyBaseAdapter extends BaseAdapter {
 
        public MyBaseAdapter(MainActivity mainActivity, int list_item, List<Sqldata> show) {
        }
 
        @Override
        public int getCount() {
            return list.size();
        }
 
        @Override
        public Object getItem(int position) {
            return null;
        }
 
        @Override
        public long getItemId(int position) {
            return position;
        }
 
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            View view = View.inflate(MainActivity.this,R.layout.item,null);
            TextView tname = (TextView)view.findViewById(R.id.t_name);
            TextView tprice = (TextView)view.findViewById(R.id.t_price);
            TextView tnumber = (TextView)view.findViewById(R.id.t_number);
 
 
            tname.setText(list.get(position).getName());
            tprice.setText(list.get(position).getPrice());
            tnumber.setText(list.get(position).getNumber());
            return view;
        }
    }
 
 
}