android实际项目中数据库的应用(增删改查)

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原创最新推荐文章于 2026-04-16 10:11:23 发布 1.5k 阅读 AI 写同款· GEO 优化 ›

Android（安卓）订餐APP(Sqlite数据库，完整的增删改查) Android（安卓）订餐APP(Sqlite数据库，完整的增删改查) 一.背景首先说说项目的背景，基于地铁口鸡蛋饼的一个小项目，APP中固定设置的鸡蛋饼搭配，顾客也可以自己搭配二.开发环境 AndroidStudio3.0.1 JDK1.8 语言：JAVA 数据存储：Sqlite 三.功能注册、登录、管理员、普通用户首页:鸡蛋饼食材搭配订单:购买订单展示 ... 阅读详情

//下面有详细的注释,

package com.ldci.db;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class DBdao{
private static final String DB_NAME="info.db";
private static final String TB_NAME="email_tab";
                             //以下声明的是存放在数据库中列名
static final String F_ID="_id";
static final String F_FROMEMAIL="fromEmail";
static final String F_PASSWORD="password";
    static final String F_TOEMAIL="toEmail";

private SQLiteDatabase db;
private DbHelper dbHelper;
private Context context;

   public DBdao(Context context){
    this.context=context;
   }
   public void open(){
    dbHelper=new DbHelper(context);
    db=dbHelper.getWritableDatabase();   //获得一个可写的数据库对象     ----这是创建数据库最常用的方法
   }
   public void close(){
    db.close();
   }
         //插入
public long addInfo(String from,String pass,String to){
    ContentValues initValues=new ContentValues();
    initValues.put(F_FROMEMAIL, from);
    initValues.put(F_PASSWORD,pass);
    initValues.put(F_TOEMAIL,to);
   return db.insert(TB_NAME, null, initValues);
}
      //删除一条数据(只删除选中的一行)    --是通过id来删除
   public long delete(long rowId){
    return db.delete(TB_NAME, F_ID+"="+rowId,null);
   }
       //清空(删除所有行)
    public long deleteAll(){
     return db.delete(TB_NAME, null,null);

    }
       //更新       --是通过Id来执行更新操作
    public long updata(long rowId,String from,String pass,String to ){
    ContentValues values=new ContentValues();
       values.put(F_FROMEMAIL, from);
       values.put(F_PASSWORD, pass);
       values.put(F_TOEMAIL, to);
     return db.update(TB_NAME, values, F_ID+"="+rowId, null);

    }
  /**
   * 查询记录
   * @return
   */
        //查询所有数据
  public Cursor getAll(){
   String sql="select * from email_tab";
   return db.rawQuery(sql,null);            //将返回一个Cursor对象,Cursor对象包含查询到的所有数据
  }
     //查询一条数据 (通过Id)
  public Cursor getData(long rowId){
   return db.rawQuery("select * from email_tab where " + F_ID +"= " + rowId , null);
  }
                        //用while读出Cursor中所有内容
   public void readCursor(Cursor cursor){
      while(cursor.moveToNext()){
      int rowId=cursor.getInt(cursor.getColumnIndex(F_ID));
      String from=cursor.getString(cursor.getColumnIndex(F_FROMEMAIL));
      String pass=cursor.getString(cursor.getColumnIndex(F_PASSWORD));
      String to=cursor.getString(cursor.getColumnIndex(F_TOEMAIL));
      //Log.d("aa",rowId+from+pass+to);

      }

   }


             //1. 创建内部类,初始化数据库及数据表
class DbHelper extends SQLiteOpenHelper{

public DbHelper(Context context) {
  super(context,DB_NAME, null,2);
}

                   // 在数据库被创建时自动调用onCreate()方法      如果数据库文件已存在,则是不会调用onCreate()方法的
@Override
public void onCreate(SQLiteDatabase db) {
  // TODO Auto-generated method stub                                 //此方法创建了一个数据库表
  String sql="create table "+TB_NAME+
     "("
   +F_ID+" integer primary key AUTOINCREMENT,"
     +F_FROMEMAIL+" text,"
     +F_PASSWORD+" text,"
     +F_TOEMAIL+" text)";
     db.execSQL(sql);

}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("drop table if exists "+TB_NAME);
onCreate(db);
}
}
}

package com.ldci.db;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
import android.widget.TextView;
import android.widget.AdapterView.OnItemClickListener;

import com.ldci.smsmessagedemo.R;

public class ShowInfoAct extends Activity implements OnItemClickListener {
private TextView tvNull1;
// 声明数据库访问对象
private DBdao dao = null;
private Cursor cursor = null;
private long listId = 0;
private SimpleCursorAdapter simpleCursorAdapter;
ListView listView= null;

@Override
protected void onCreate(Bundle savedInstanceState) {
  // TODO Auto-generated method stub
  super.onCreate(savedInstanceState);
  setContentView(R.layout.showinfo); // 首先加载的是含有ListView组件的布局文件
                          //先取得代表ListView控件的对象
  listView = (ListView) findViewById(R.id.list);
  dao = new DBdao(ShowInfoAct.this);
  dao.open();     //打开数据库
        readerListView();

//  if(listView.getCount()==0){
//   tvNull1=(TextView)findViewById(R.id.tvNull);
//    tvNull1.setText("NO Data...........");
//  }

// registerForContextMenu(list); // 为视图注册上下文菜单
}
                       //用simpleCursorAdapter对象将cursor中的数据显示在ListView上
private void readerListView() {
  cursor = dao.getAll();
  if(cursor.getCount()==0){                    //首先判断是在没有Cursor数据时,将会出现提示信息"No data...."
   tvNull1=(TextView)findViewById(R.id.tvNull);
    tvNull1.setText("NO Data...........");
  }
  String [] key={dao.F_FROMEMAIL,dao.F_PASSWORD,dao.F_TOEMAIL};    //数据库的列名
  int[] values={R.id.tvFromemail,R.id.tvPassword,R.id.tvToemail};          //对应在数据库每一列中该显示的内容--都是XML中的TextView的Id
  simpleCursorAdapter = new SimpleCursorAdapter(ShowInfoAct.this,R.layout.showinfoself, cursor, key,values);
  listView.setAdapter(simpleCursorAdapter);
  listView.setOnItemClickListener(this);
}
         //listView的点击事件   (position标识Item的位置)
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,long id) {
  // TODO Auto-generated method stub
  cursor.moveToPosition(position);
  final String itemId = cursor.getString(cursor.getColumnIndex(dao.F_ID));
  final String from = cursor.getString(cursor.getColumnIndex(dao.F_FROMEMAIL));
  final String pass = cursor.getString(cursor.getColumnIndex(dao.F_PASSWORD));
  final String to = cursor.getString(cursor.getColumnIndex(dao.F_TOEMAIL));
//  Log.d("aa",itemId);
//  Log.d("aa",from);
  String[] s = { "修改", "删除", "查看","清空"};

           //调用AlertDialog的内部类Builder类来创建AlertDialog对象,,,之后通过Builder类show()方法显示对话框
  new AlertDialog.Builder(ShowInfoAct.this).setItems(s,
    new DialogInterface.OnClickListener() {

     @Override
     public void onClick(DialogInterface dialog, int which) {
      // TODO Auto-generated method stub
      switch (which) {
      case 0:         //执行修改
                             Intent intent1 =new Intent(ShowInfoAct.this,UpdateEmailAct.class);
         Bundle bundle1=new Bundle();
         bundle1.putString("itemId",itemId);
         bundle1.putString("from", from);
         bundle1.putString("pass", pass);
         bundle1.putString("to", to);
         intent1.putExtras(bundle1);
         startActivity(intent1);

         break;
      case 1:    //删除
        dao.delete(Integer.parseInt(itemId)); // 数据库对象调用删除方法
         readerListView();
       break;
      case 2:   //查看
                                Intent intent2=new Intent(ShowInfoAct.this,UpdateEmailAct.class);
                                Bundle bundle2=new Bundle();
                                bundle2.putString("itemId", itemId);
                                bundle2.putString("from",from);
                                bundle2.putString("pass", pass);
                                bundle2.putString("to",to);
                                intent2.putExtras(bundle2);
                               startActivity(intent2);
                               break;
      case 3:          //清空
        dao.deleteAll();
        readerListView();
        break;


      }

}
}).show();

}

package com.ldci.db;

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.content.SharedPreferences;
import android.database.Cursor;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.SimpleCursorAdapter;
import android.widget.Toast;

import com.ldci.smsmessagedemo.R;
import com.ldci.smsmessagedemo.StoreActivity;

public class UpdateEmailAct extends Activity {
    private Button butEmail2;
    private EditText editEmail,editPass,editTarget;
    public static String emailStr,passStr,targetStr;
    public String fromStrPre,passPre,toStrPre;
    public static String fromStrPreStatic,passPreStatic,toStrPre2Static;
    private CheckBox cbSave;
    private ProgressDialog myDialog=null;
    private DBdao dao;
    String id,from,pass,to;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.valemail);
        init();
         dao=new DBdao(this);
    dao.open(); //打开一个数据库
        onClickBut();
        changeCheck();             //将会调用checkBox的监听事件,将判断checkbooks是否改变


       Intent intent=getIntent();                  //接收到ShowInfoAct界面传来的数据
        Bundle bundle=intent.getExtras();
         id=bundle.getString("itemId");
         from=bundle.getString("from");
         pass=bundle.getString("pass");
         to=bundle.getString("to");
//         Log.d("aa", from);
         editEmail.setText(from);
         editPass.setText(pass);
         editTarget.setText(to);
         StoreActivity.getStoreActivity().addActivity(this);
    }
    public void onResume(){
    super.onResume();
        cbSave.setChecked(true);
//        load();
         changeCheck();                    //将会调用checkBox的监听事件,将判断checkbox是否改变
    }
                //通过id取得代表控件的对象
    public void init(){
    editEmail=(EditText)findViewById(R.id.editEmail1);
    editPass=(EditText)findViewById(R.id.editPass1);
    editTarget=(EditText)findViewById(R.id.editTarget);
    butEmail2=(Button) findViewById(R.id.go);
    cbSave=(CheckBox)findViewById(R.id.checkBoxSave1);

    }
       public void onClickBut(){                //为"确定"按钮绑定监听事件
        butEmail2.setOnClickListener(new OnClickListener(){
    @Override
    public void onClick(View v) {

      if(cbSave.isChecked()){     //被选中则是True
       save();
       Log.d("aa","cb is Checked.....");
         }

           //显示Progress对话框
     myDialog=ProgressDialog.show(UpdateEmailAct.this, "正在验证信息", "请稍后........");
        //取得用户输入的信息
           emailStr=editEmail.getText().toString().trim();   //将用户输入的email转化为字符串并且去掉前后空格
        passStr=editPass.getText().toString().trim();     //取得密码
        targetStr=editTarget.getText().toString().trim();
         new Thread(){
       public void run(){
       try {
        Thread.sleep(2000);

       } catch (Exception e) {
        e.printStackTrace();
       }finally{
        //卸载所创建的myDialog对象
        myDialog.dismiss();
        Message msg=handler.obtainMessage();
        msg.arg1=1;
        handler.sendMessage(msg);
       }
       }
      }.start();
      }
          });
       }
    Handler handler=new Handler(){
@Override
  public void handleMessage(Message msg) {
   // TODO Auto-generated method stub
   super.handleMessage(msg);

     Toast.makeText(UpdateEmailAct.this,"\n----Email----\n"+emailStr+"\n--- Password----\n"+passStr,Toast.LENGTH_LONG).show();
   Intent intent=UpdateEmailAct.this.getIntent();
   Bundle bundle=new Bundle();
   bundle.putString("email", emailStr);
   intent.putExtras(bundle);
   Toast.makeText(UpdateEmailAct.this,"您的Email及password相匹配,开启了自动备份功能...",Toast.LENGTH_SHORT).show();
   UpdateEmailAct.this.setResult(RESULT_OK,intent );
   UpdateEmailAct.this.finish();
  }
    };
      public void changeCheck(){
       cbSave.setOnClickListener(new OnClickListener(){
   @Override
   public void onClick(View v) {
   }
     });
       }


      public static String fileName="valContent";
      private int mode=Activity.MODE_PRIVATE;

      public void save(){            //保存数据
       SharedPreferences settings=getSharedPreferences(fileName,mode);
       SharedPreferences.Editor ed=settings.edit();
       ed.putString("fromEmail", editEmail.getText().toString().trim());
       ed.putString("password", editPass.getText().toString().trim());
       ed.putString("toEmail",editTarget.getText().toString().trim());
       ed.commit();                 //保存key-value对

      }

       public void load(){             //读取数据
        SharedPreferences settings=getSharedPreferences(fileName, mode);
        fromStrPre=settings.getString("fromEmail","******@163.com");
        passPre=settings.getString("password","********");
        toStrPre=settings.getString("toEmail","****@126.com");
        fromStrPreStatic=fromStrPre;
        passPreStatic=passPre;
        toStrPre2Static=toStrPre;
        editEmail.setText(fromStrPre);         //将得到的值放到EditText中 ,显示出来
        editPass.setText(passPre);
        editTarget.setText(toStrPre);
       }
@Override
public boolean onCreateOptionsMenu(Menu menu) {
  // TODO Auto-generated method stub
  menu.add(1,1,1,"收藏").setIcon(R.drawable.save);

  return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
  // TODO Auto-generated method stub
  switch(item.getItemId()){
  case 1:
      emailStr=editEmail.getText().toString().trim();   //将用户输入的email转化为字符串并且去掉前后空格
      passStr=editPass.getText().toString().trim();     //取得密码
      targetStr=editTarget.getText().toString().trim();

      Long count=dao.updata(Integer.parseInt(id), emailStr, passStr, targetStr);    //调用dao中的更新操作
     if(count>0){
    Intent intent=new Intent(UpdateEmailAct.this,ShowInfoAct.class);
    startActivity(intent);
     Toast.makeText(this,"保存成功", Toast.LENGTH_LONG).show();
    }else{
     Toast.makeText(this,"保存失败", Toast.LENGTH_LONG).show();
    }


//      dao.updata(id, editEmail.getText().toString(), editPass.getText().toString(), editTarget.getText().toString());
//    Long id=dao.addInfo("FromEmail:"+emailStr, "Password:"+passStr, "ToEmail:"+targetStr);
//    if(id>0){
//     Toast.makeText(this,"保存成功", Toast.LENGTH_LONG).show();
//    }else{
//     Toast.makeText(this,"保存失败", Toast.LENGTH_LONG).show();
//    }
// Intent intent=new Intent(this,ShowInfoAct.class);
//    startActivity(intent);
    dao.close();     //关闭数据库对象
       this.finish();           //关闭当前的Act

    break;

  }
  return super.onOptionsItemSelected(item);
}



}