android下对sqlite 进行增删改查和事务操作的实例

package com.example.mytool;

public class person {
private int userid;
private String username;
public int getUserid() {
return userid;
}
public void setUserid(int userid) {
this.userid = userid;
}
public String getUsername() {
return username;
}
public person() {
}
public person(int userid, String username) {
this.userid = userid;
this.username = username;
}
public void setUsername(String username) {
this.username = username;
}
@Override
public String toString() {
return "person [userid=" + userid + ", username=" + username + "]";
}

}

package com.example.mytool;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class mydbconnect extends SQLiteOpenHelper {

public mydbconnect(Context context) {
super(context, "liyihang.db", null, 1);
// TODO Auto-generated constructor stub
}

@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("create table user(userid integer primary key autoincrement , username varchar(50) );");
}

@Override
public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
// TODO Auto-generated method stub

}

}

package com.example.mytool;

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

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

public class mydb {
private SQLiteDatabase db;
public mydb(){}
/*
* 获取数据操作对象
* */
public mydb(Context context) throws Exception {
mydbconnect con=new mydbconnect(context);
db=con.getWritableDatabase();
}
/*
* 增加数据
* */
public void minsert() throws Exception{
db.execSQL("insert into  user(username) values('liyihang')");
}
/*
* 更新数据
* */
public void mupdate() throws Exception{
db.execSQL("update user set username='nihao' where userid=1");
}
/*
* 删除操作
* */
public void mdelete() throws Exception{
db.execSQL("delete from user where userid=1");
}
/*
* 获取单条数据
* */
public person mrow() throws Exception{
person pson=null;
Cursor re=db.rawQuery("select * from user where userid=?", new String[]{"1"});
if(re.moveToFirst()){
int userid=re.getInt(re.getColumnIndex("userid"));
String username=re.getString(re.getColumnIndex("username"));
pson=new person(userid,username);
}
return pson;
}
/*
* 获取分页数据
* */
public List<person> getlist() throws Exception{
List<person> psons=new ArrayList<person>();
person pson=null;
Cursor re=db.rawQuery("select * from user order by userid desc", null);
while(re.moveToNext()){
int userid=re.getInt(re.getColumnIndex("userid"));
String username=re.getString(re.getColumnIndex("username"));
pson=new person(userid,username);
psons.add(pson);
}
re.close();
return psons;
}
/*
* 事务处理方案
*
* */
public void shiwu() throws Exception{
db.beginTransaction();
db.execSQL("update user set username='wohsiliyihang' where userid=3");
db.execSQL("update user set username='hah' where userid=4");
db.setTransactionSuccessful();
db.endTransaction();
}
/*
* 获取记录总数
* */
public int count() throws Exception{
int nums=0;
Cursor re=db.rawQuery("select count(*) from user", null);
re.moveToFirst();
nums=re.getInt(0);
return nums;
}

}

package com.example.mytool;

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

import android.os.Bundle;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends Activity {

/** Called when the activity is first created. */
@SuppressLint("SetJavaScriptEnabled")
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}

public void index_btn(View v){
try {
mydb db=new mydb(this);
db.shiwu();
Toast.makeText(getApplicationContext(), "ok", Toast.LENGTH_LONG).show();

} catch (Exception e) {
// TODO Auto-generated catch block
Toast.makeText(getApplicationContext(), "no", Toast.LENGTH_LONG).show();
e.printStackTrace();
}

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

}