SQLite数据库是android系统自带的数据库，小巧使用方便。

最常见的就是电话簿。

电话簿数据库存在的位置位于（如图）：

可以用SQLiteManager打开。

在android中使用SQLiteDatabase就能直接对数据库操作。

下面用一个demo实现数据库的创建、表的创建和删除、表中数据的增删改查。

架构如下：

布局文件main实现简单的功能：

1 ?xml version="1.0" encoding="utf-8"?>76

工具类DBUtil.java是实现数据库的创建连接、断接、增删改查等操作。

package com.db.util;import java.util.ArrayList;import java.util.List;import java.util.Vector;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.util.Log;import android.widget.EditText;public class DBUtil static SQLiteDatabase sld; public static void createOrOpenDatabase() throws Exception sld=SQLiteDatabase.openDatabase "/data/data/com.db/dbtest", //数据库所在路径 null, //CursorFactory SQLiteDatabase.OPEN_READWRITE|SQLiteDatabase.CREATE_IF_NECESSARY //读写、若不存在则创建 String sql0="create table if not exists user(username varchar2(20),password varchar2(20))"; sld.execSQL(sql0); public static void closeDatabase() throws Exception sld.close(); catch(Exception e) e.printStackTrace(); /*=====================================begin==========================================================*/ //获取用户信息-winxiang public static List searchuser(String username){ List list=new ArrayList(); createOrOpenDatabase(); String sql="select * from user where username='"+username+"'"; Cursor cur=sld.rawQuery(sql, new String[]{}); while(cur.moveToNext()) list.add(cur.getString(0)); //username list.add(cur.getString(1)); //password cur.close(); closeDatabase(); catch(Exception e) e.printStackTrace(); return list; //获取所有用户信息-winxiang public static List searchalluser(){ List list=new ArrayList(); createOrOpenDatabase(); String sql="select * from user"; Cursor cur=sld.rawQuery(sql, new String[]{}); while(cur.moveToNext()) list.add(cur.getString(0)); //username list.add(cur.getString(1)); //password cur.close(); closeDatabase(); catch(Exception e) e.printStackTrace(); return list; public static void updatetable(String sql) createOrOpenDatabase(); sld.execSQL(sql); closeDatabase(); catch(Exception e) e.printStackTrace(); //舍弃user表 public static void droptable(){ String sql="drop table user"; createOrOpenDatabase(); sld.execSQL(sql); closeDatabase(); catch(Exception e) e.printStackTrace(); Log.d("DB","had deleted table: user->"); /*=====================================end==========================================================*/}

DBTestactivity：

1 package com.db; 4 import java.util.List; 6 import com.db.util.DBUtil; 7 import android.app.Activity; 8 import android.os.Bundle; 9 import android.view.View;10 import android.view.View.OnClickListener;11 import android.widget.Button;12 import android.widget.EditText;13 import android.widget.TextView;14 import android.widget.Toast;16 public class DBtestActivity extends Activity {17 Button btn_createdb,btn_insert,btn_show,btn_update,btn_showall,deleteusertable;18 EditText username,password;19 TextView showsomething;21 @Override22 public void onCreate(Bundle savedInstanceState) {23 super.onCreate(savedInstanceState);24 setContentView(R.layout.main);25 init();28 public void init(){29 username = (EditText) findViewById(R.id.username);30 password = (EditText) findViewById(R.id.password);31 btn_createdb = (Button) findViewById(R.id.btn_create);32 btn_insert = (Button) findViewById(R.id.btn_insert);33 btn_show = (Button) findViewById(R.id.btn_show);34 btn_update = (Button) findViewById(R.id.btn_update);35 deleteusertable = (Button) findViewById(R.id.btn_deleteusertable);36 btn_showall= (Button) findViewById(R.id.btn_showall);37 showsomething = (TextView) findViewById(R.id.showsomething);39 btn_createdb.setOnClickListener(listener);40 btn_insert.setOnClickListener(listener);41 btn_createdb.setOnClickListener(listener);42 btn_show.setOnClickListener(listener);43 btn_update.setOnClickListener(listener);44 btn_showall.setOnClickListener(listener);45 deleteusertable.setOnClickListener(listener);48 public OnClickListener listener = new OnClickListener() {49 @Override50 public void onClick(View v) {51 Button button = (Button) v;52 if(button.getId()==btn_createdb.getId()){53 try {54 DBUtil.createOrOpenDatabase(); 55 } catch (Exception e) {56 e.printStackTrace();58 }else if(button.getId()==btn_insert.getId()){59 String sql="insert into user values ('"+username.getText()+"','"+password.getText()+"')";60 DBUtil.updatetable(sql);61 }else if(button.getId()==btn_show.getId()){62 Listuser = DBUtil.searchuser(username.getText().toString());63 showsomething.setText(user.toString());64 }else if(button.getId()==btn_update.getId()){65 String sql="update user set username='"+username.getText()+"',password='"+password.getText()+"' where username = '"+username.getText()+"'";66 System.out.println(sql);67 DBUtil.updatetable(sql);68 }else if(button.getId()==btn_showall.getId()){69 Listusers = DBUtil.searchalluser();70 showsomething.setText(users.toString());71 }else if(button.getId()==deleteusertable.getId()){72 DBUtil.droptable();73 Toast.makeText(getApplicationContext(), "用户表删除成功", Toast.LENGTH_SHORT).show();76 };77 }

效果图如下：