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本文介绍: 从SQLite数据库中获取信息传给List View，并对List View进行相关的增删改查操作！

完成效果如图所示：

首先编写首页的样式：（ activity_goods.xml ）

<?xml version="1.0" encoding="utf-8"?&gt;
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent"&gt;


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"&gt;

        <EditText
            android:layout_width="180dp"
            android:layout_height="50dp"
            android:hint="商品名称"
            android:id="@+id/et_name"/&gt;
        <EditText
            android:layout_width="180dp"
            android:layout_height="50dp"
            android:inputType="number"
            android:hint="金额"
            android:id="@+id/et_price"/&gt;
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="+"
            android:textSize="30dp"
            android:id="@+id/btn_add"/>
        


    </LinearLayout>
    <ListView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/lv_goods"/>
</LinearLayout>

其次对ListView中item样式进行设置（  activity_good_item.xml ）

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="80dp"
        android:layout_marginTop="10dp">

        <TextView
            android:layout_width="125dp"
            android:layout_height="80dp"

            android:text="商品名"
            android:textSize="36dp"
            android:id="@+id/tv_detial1"/>
        <TextView
            android:layout_width="90dp"
            android:layout_height="80dp"
            android:text=" 金额"
            android:textSize="36dp"
            android:id="@+id/tv_detial2"/>
        <EditText
            android:layout_width="100dp"
            android:layout_height="80dp"
            android:hint="修改的金额"
            android:inputType="number"
            android:id="@+id/et_edit"/>

        <Button
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:text="修改"
            android:textSize="23dp"
            android:id="@+id/btn_updategood"/>
        <Button
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:text="删除"
            android:textSize="23dp"
            android:id="@+id/btn_deletegood"/>
    </LinearLayout>

</LinearLayout>

编写适配器 MyAdapter

package com.example.sqlitedemo.adapter;

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import com.example.sqlitedemo.GoodActivity;
import com.example.sqlitedemo.GoodBean;
import com.example.sqlitedemo.R;

import java.util.List;

public class MyAdapter extends BaseAdapter {

    private List<GoodBean> goodlist;
    private LayoutInflater layoutInflater;
    private Context context;
    private Callback mCallback;


    public MyAdapter(List<GoodBean> goodlist, Context context,Callback callback) {
        this.goodlist = goodlist;
        this.context =context;
        layoutInflater = LayoutInflater.from(context);
        mCallback = callback;
    }

    public interface Callback {
       void click(View v);
       void click1(View v,String content);
    }

    @Override
    public int getCount() {
        return goodlist!=null?goodlist.size():0;
    }

    @Override
    public Object getItem(int i) {
        return goodlist.get(i);
    }

    @Override
    public long getItemId(int i) {
        return i;
    }

    @Override
    public View getView(final int i, View view, ViewGroup parent) {
        ViewHolder viewHolder = new ViewHolder();
        if (view == null){
            view =layoutInflater.inflate(R.layout.activity_good_item,null);
            TextView etDetail1 = view.findViewById(R.id.tv_detial1);
            TextView etDetail2 = view.findViewById(R.id.tv_detial2);
            Button btn1 = view.findViewById(R.id.btn_updategood);
            Button btn2 = view.findViewById(R.id.btn_deletegood);
            EditText etedit = view.findViewById(R.id.et_edit);

            viewHolder.etDetail1 = etDetail1;
            viewHolder.etDetail2 = etDetail2;
            viewHolder.btn1 = btn1;
            viewHolder.btn2 = btn2;
            viewHolder.etedit = etedit;

            view.setTag(viewHolder);

        }else {
            viewHolder = (ViewHolder) view.getTag();
        }




        final GoodBean goodBean = goodlist.get(i);

        viewHolder.etDetail1.setText(goodBean.getGoodname());
        viewHolder.etDetail2.setText(String.valueOf(goodBean.getPrice()));
        viewHolder.btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(final View view) {

                AlertDialog alertDialog = new AlertDialog.Builder(view.getContext()).setMessage("确定删除 "+goodlist.get(i).getGoodname()+" 吗？").setIcon(R.mipmap.ic_launcher)
                        .setPositiveButton("确定", new DialogInterface.OnClickListener() {//添加"Yes"按钮
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        mCallback.click(view);
                    }
                })
                        .setNegativeButton("取消", new DialogInterface.OnClickListener() {//添加取消
                            @Override
                            public void onClick(DialogInterface dialogInterface, int i) {
                                Toast.makeText(view.getContext(), "已取消删除", Toast.LENGTH_SHORT).show();
                            }
                        }).create();

                alertDialog.show();


            }
        });
        viewHolder.btn2.setTag(i);
        final ViewHolder finalViewHolder = viewHolder;
        viewHolder.btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(final View view) {
                final String content = finalViewHolder.etedit.getText().toString();


                AlertDialog alertDialog = new AlertDialog.Builder(view.getContext()).setMessage("确定将 "+goodlist.get(i).getGoodname()+" 的价格从 "+goodlist.get(i).getPrice()+" 更改为 "+content+" 吗？").setIcon(R.mipmap.ic_launcher)
                        .setPositiveButton("确定", new DialogInterface.OnClickListener() {//添加"Yes"按钮
                            @Override
                            public void onClick(DialogInterface dialogInterface, int i) {
                                mCallback.click1(view,content);
                            }
                        })
                        .setNegativeButton("取消", new DialogInterface.OnClickListener() {//添加取消
                            @Override
                            public void onClick(DialogInterface dialogInterface, int i) {
                                Toast.makeText(view.getContext(), "已取消修改", Toast.LENGTH_SHORT).show();
                            }
                        }).create();

                alertDialog.show();

            }
        });
        viewHolder.btn1.setTag(i);
        return view;
    }

    class ViewHolder{
        TextView etDetail1;
        TextView etDetail2;
        Button btn1;
        Button btn2;
        EditText etedit;
    }
}

GoodActivity

package com.example.sqlitedemo;

import android.app.Activity;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Adapter;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import com.example.sqlitedemo.adapter.MyAdapter;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;


public class GoodActivity extends Activity implements AdapterView.OnItemClickListener, MyAdapter.Callback {

    ListView lvGood;
    Button btnAdd;
    EditText etGname;
    EditText etGprice;
    GoodDao goodDao;
    MyAdapter myAdapter;
    List<GoodBean> goodlist;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_goods);

        goodDao = new GoodDao(this);
        btnAdd = findViewById(R.id.btn_add);
        etGname = findViewById(R.id.et_name);
        etGprice = findViewById(R.id.et_price);
        lvGood = findViewById(R.id.lv_goods);

        initView();
        initDate();
        initEvent();

        btnAdd.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String goodname = etGname.getText().toString();
                String price = etGprice.getText().toString();
                if (!(TextUtils.isEmpty(goodname)||TextUtils.isEmpty(price))){
                    int goodprice = Integer.valueOf(price);
                    boolean flag = goodDao.insertGood(goodname,goodprice);
                    if(flag){
                        Toast.makeText(getApplicationContext(),"添加成功",Toast.LENGTH_SHORT).show();
                        initView();
                        initDate();
                        initEvent();
                    }else {
                        Toast.makeText(getApplicationContext(),"添加失败",Toast.LENGTH_SHORT).show();
                    }
                }else {
                    Toast.makeText(getApplicationContext(),"请输入相关信息",Toast.LENGTH_SHORT).show();
                }

                etGname.setText("");
                etGprice.setText("");
            }
        });

    }

    private void initEvent() {
        myAdapter = new MyAdapter(goodlist,this,this);
        lvGood.setAdapter(myAdapter);
        lvGood.setOnItemClickListener(this);

    }

    private void initDate() {

        goodlist = new ArrayList<>();

        goodlist = goodDao.seleteAll();

    }

    private void initView() {
    }

    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
        Toast.makeText(this, "listview的item被点击了！，点击的位置是-->" + i,Toast.LENGTH_SHORT).show();
    }


    @Override
    public void click(View v) {

        boolean flag = goodDao.deleteGood(goodlist.get((Integer)v.getTag()).getGoodname());
        if(flag){
            Toast.makeText(GoodActivity.this,"删除成功！",Toast.LENGTH_SHORT).show();
            initView();
            initDate();
            initEvent();
        }else {
            Toast.makeText(GoodActivity.this,"删除失败！",Toast.LENGTH_SHORT).show();
        }


    }

    @Override
    public void click1(View v,String content) {
        if (!TextUtils.isEmpty(content)){
            Integer content1 = Integer.valueOf(content);
            String name = goodlist.get((Integer) v.getTag()).getGoodname();
            boolean flag =  goodDao.updategood(name,content1);
            if(flag){
                Toast.makeText(GoodActivity.this,"修改成功 ！",Toast.LENGTH_SHORT).show();
                initView();
                initDate();
                initEvent();
            }else {
                Toast.makeText(GoodActivity.this,"修改失败 ！",Toast.LENGTH_SHORT).show();
            }
        }else {
            Toast.makeText(GoodActivity.this,"请输入修改金额",Toast.LENGTH_SHORT).show();
        }
    }
}

GoodBean

package com.example.sqlitedemo;

public class GoodBean {
    private int id;
    private String goodname;

    @Override
    public String toString() {
        return "GoodBean{" +
                "id=" + id +
                ", goodname='" + goodname + ''' +
                ", price=" + price +
                '}';
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getGoodname() {
        return goodname;
    }

    public void setGoodname(String goodname) {
        this.goodname = goodname;
    }

    public int getPrice() {
        return price;
    }

    public void setPrice(int price) {
        this.price = price;
    }

    private int price;
}

GoodDao

package com.example.sqlitedemo;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

import java.util.ArrayList;
import java.util.List;

public class GoodDao {

    private SQLiteDatabase sqLiteDatabase;

    public GoodDao(Context context) {
        //初始化刚刚写的MySQLiteHelper对象
        MySQLiteHelper mySQLiteHelper = new MySQLiteHelper(context);
        //获取sqLiteDatabase对象
        sqLiteDatabase = mySQLiteHelper.getWritableDatabase();
    }
    public boolean insertGood(String goodname,int price){
        ContentValues values = new ContentValues();
        values.put("goodname",goodname);
        values.put("price",price);
        //第一个是表名，第二个null，第三个是相当于sql插入语句的values
        //id用于判断是否插入成功： 如果大于0则表示插入了至少一条数据，否则插入失败
        long id = sqLiteDatabase.insert("good",null,values);
        return id>0?true:false;
    }

    public List<GoodBean> seleteAll(){
        List<GoodBean> goodlist = new ArrayList<>();
        Cursor cursor = sqLiteDatabase.rawQuery("select * from good",null);
        while (cursor.moveToNext()) {
            GoodBean goodBean = new GoodBean();
            goodBean.setGoodname(cursor.getString(cursor
                    .getColumnIndex("goodname")));
            goodBean.setPrice(cursor.getInt(cursor
                    .getColumnIndex("price")));
            goodlist.add(goodBean);
        }
        return goodlist;
    }


    public boolean deleteGood(String goodname){
        long id = sqLiteDatabase.delete("good","goodname = ?",new String[]{goodname});
        return id>0?true:false;
    }


    public boolean updategood(String goodname,int price){
        boolean flag;
        ContentValues values = new ContentValues();
        values.put("price",price);
        long id = sqLiteDatabase.update("good",values,"goodname = ? ",new String[]{goodname});
        flag = id > 0?true : false;
        return flag;
    }

}

相关MySQLiteHelper可参考 ：Android 对 SQLite 的相关操作

原文地址:https://blog.csdn.net/qq_45969735/article/details/123420056

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