android实际项目中数据库的应用(增删改查)

//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);

}

}