安卓中对SQLite数据库的增删改查

安卓中对SQLite数据库的增删改查第⼀步:编写⼀个javaBeanpackagecom.itfom.entity;publicclassPerson{privateStringname;privateintage;privateStringphone;publicStringgetName(){returnname;}publicvoidsetName(Stringname){=name;}publicintgetAge(){returnage;}publicvoidsetAge(intage){this.age=age;}publicStringgetPhone(){returnphone;}publicvoidsetPhone(Stringphone){this.phone=phone;}//创建构造函数publicPerson(){}publicPerson(Stringname,intage,Stringphone){=name;this.age=age;this.phone=phone;}//重写toString@OverridepublicStringtoString(){return"姓名:"+name+"年龄:"+age+"电话:"+phone+"\n";}}第⼆步:创建数据库packagepackagecom.itfom.helper;importandroid.content.Context;importandroid.database.sqlite.SQLiteDatabase;importandroid.database.sqlite.SQLiteOpenHelper;publicclassOpenHelperextendsSQLiteOpenHelper{publicOpenHelper(Contextcontext){//这三个参数分别为上下⽂对象,数据库名称,游标,版本号super(context,"xsc.db",null,1);}@OverridepublicvoidonCreate(SQLiteDatabasedb){db.execSQL("createtableperson(namevarchar(50),ageinteger,phonevarchar(50))");}@OverridepublicvoidonUpgrade(SQLiteDatabasedb,intoldVersion,intnewVersion){//注：⽣产环境上不能做删除操作db.execSQL("DROPTABLEIFEXISTSperson");onCreate(db);}}第三步:创建数据库的操作类packagecom.itfom.entitydao;importjava.util.ArrayList;importjava.util.List;importandroid.content.Context;importandroid.database.Cursor;importandroid.database.sqlite.SQLiteDatabase;importcom.itfom.entity.Person;importcom.itfom.helper.OpenHelper;publicclassPersonDao{privateOpenHelperhelper=null;/**构造函数getWritableDatabase()或getReadableDatabase()SQLiteDatabase实例；因为这⾥是⼿机应⽤程序，⼀般只有⼀个⽤户访问数据库，所以建议不关闭数据库，保持连接状态。getWritableDatabase()，getReadableDatabase的区别是当数据库写满时，调⽤前者会报错，调⽤后者不会，所以如果不是更新数据库的话，最好调⽤后者来获得数据库连接。SQLexeSQL(),rawQuery(),因为⽐较直观明了@paramcontext*/publicPersonDao(Contextcontext){helper=newOpenHelper(context);}//实现对该数据库的增加publicvoidaddPerson(Personperson){//获取操作实例SQLiteDatabasedb=helper.getWritableDatabase();/StringsqlStr="insertintoperson(name,age,phone)values(?,?,?)";//执⾏SQL语句db.execSQL(sqlStr,newObject[]{person.getName(),person.getAge(),person.getPhone()});db.execSQL(sqlStr,newObject[]{person.getName(),person.getAge(),person.getPhone()});//关闭数据库db.close();}//实现对数据库的删除publicvoiddeletePerson(Stringname){//获取数据库操作的实例SQLiteDatabasedb=helper.getWritableDatabase();//创建SQL字符串StringsqlStr="deletefrompersonwherename=?";db.execSQL(sqlStr,newString[]{name});//关闭数据库db.close();}//实现对数据库的修改publicvoidupdatePerson(Personperson){//获取数据库的操作实例SQLiteDatabasedb=helper.getWritableDatabase();//创建SQl字符串StringsqlStr="updatepersonsetname=?,phone=?whereage=?";//执⾏SQL语句db.execSQL(sqlStr,newObject[]{person.getName(),person.getPhone(),person.getAge()});//关闭数据库db.close();}//实现对数据库的查询publicList<Person>selectPerson(){//创建集合List<Person>persons=newArrayList<Person>();//获取数据库操作实例SQLiteDatabasedb=helper.getReadableDatabase();//创建Cursor对象Cursorcursor=null;try{cursor=db.rawQuery("select*fromperson",null);while(cursor.moveToNext()){Stringname=cursor.getString(cursor.getColumnIndex("name"));intage=cursor.getInt(cursor.getColumnIndex("age"));Stringphone=cursor.getString(cursor.getColumnIndex("phone"));//创建Person对象Personp=newPerson(name,age,phone);//将创建出来的Person对象添加到集合中去persons.add(p);}}catch(Exceptione)e.printStackTrace();}finally{//关闭相应的资源if(cursor!=null){cursor.close();}if(db!=null){db.close();}}returnpersons;}}packagecom.itfom.sqlite;importjava.util.List;importandroid.app.Activity;importandroid.app.Activity;importandroid.os.Bundle;importandroid.view.View;importandroid.view.View.OnClickListener;importandroid.widget.Button;importandroid.widget.Toast;importcom.itfom.entity.Person;importcom.itfom.entitydao.PersonDao;publicclassMainActivityextendsActivityimplementsOnClickListener{//寻找控件Buttonbtn_add,btn_delete,btn_update,btn_select;//创建数据库操作类的实例PersonDaopd=null;List<Person>persons=null;@OverrideprotectedvoidonCreate(BundlesavedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);init();}init(){//初始化控件btn_add=(Button)findViewById(R.id.btn_add);btn_delete=(Button)findViewById(R.id.btn_delete);btn_update=(Button)findViewById(R.id.btn_update);btn_select=(Button)findViewById(R.id.btn_select);pd=newPersonDao(this);//为每个控件设置监听事件btn_add.setOnClickListener(this);btn_delete.setOnClickListener(this);btn_update.setOnClickListener(this);btn_select.setOnClickListener(this);}@OverridepublicvoidonClick(Viewv){switch(v.getId()){caseR.id.btn_add://添加数据//创建Person对象for(inti=0;i<100;i++){Personp=newPerson("夏守成"+i,i,"1809527282");pd.addPerson(p);}Toast.makeText(this,"添加数据成功",Toast.LENGTH_SHORT).show();break;caseR.id.btn_delete://删除数据pd.deletePerson("夏守成0");Toast.makeText(this,"删除数据成功",Toast.LENGTH_SHORT).show();break;caseR.id.btn_update://更新数据//创建Person对象Personp=newPerson("刘丹",21,"110");pd.updatePerson(p);Toast.makeText(this,"数据更新成功",Toast.LENGTH_SHORT).show();break;caseR.id.btn_selec