android之sqlite实现增删改查

android之sqlite实现增删改查Sqlite实现简单的增删改查主界⾯：功能实现：增加数据：：ID删除6)ID查询：7）ID更新：主要代码段：DBOpenHelper.javapackagecom.chen.dao;importandroid.content.Context;importandroid.database.sqlite.SQLiteDatabase;importandroid.database.sqlite.SQLiteOpenHelper;importandroid.util.Log;publicclassDBOpenHelperextendsSQLiteOpenHelper{privatestaticfinalintVERSION=2;//版本privatestaticfinalStringDBNAME="user.db";//创建数据库publicDBOpenHelper(Contextcontext){super(context,DBNAME,null,VERSION);}@Override/**创建表*/publicvoidonCreate(SQLiteDatabasedb){db.execSQL("createtableifnotexistsu_user(_idintegerprimarykey,namevarchar(20),ageinteger,tallvarchar(5))");}//版本被更新时执⾏@OverridepublicvoidonUpgrade(SQLiteDatabasedb,intoldVersion,intnewVersion){}}UserDAO.javapackagecom.chen.dao;importjava.util.ArrayList;importjava.util.List;import/doc/299973411.htmler;importandroid.content.Context;importandroid.database.Cursor;importandroid.database.sqlite.SQLiteDatabase;publicclassUserDAO{privateDBOpenHelperhelper;//写⼊，不然会是出错，是空指针publicUserDAO(Contextcontext){helper=newDBOpenHelper(context);}/***添加⽤户信息*/publicvoidadd(Useruser){SQLiteDatabasedb=helper.getWritableDatabase();Stringsql="Insertintou_user(_id,name,age,tall)values(?,?,?,?)";db.execSQL(sql,newObject[]{user.getId(),user.getName(),user.getAge(),user.getTall()});db.close();}/***删除⽤户信息*/publicvoiddelete(Integer...id){if(id.length>0){StringBuffersb=newStringBuffer();for(inti=0;isb.append("?").append(",");}sb.deleteCharAt(sb.length()-1);SQLiteDatabasedatabase=helper.getWritableDatabase();Stringsql="deletefromu_userwhere_idin("+sb+")";database.execSQL(sql,(Object[])id);}}/***删除表⾥的全部数据*/publicvoiddelelteall(){SQLiteDatabasedatabase=helper.getWritableDatabase();Stringsql="deletefromu_user";database.execSQL(sql);}/***⽤户修改*/publicvoidupdate(Useruser){SQLiteDatabasedb=helper.getWritableDatabase();//写⼊数据库中注意不能放在外⾯Stringsql="updateu_usersetname=?,age=?,tall=where_id=?";db.execSQL(sql,newObject[]{user.getName(),user.getAge(),user.getTall(),user.getId()});}/***查找⽤户信息*/publicUserfind(intuserid){SQLiteDatabasedb=helper.getWritableDatabase();//写⼊数据库中注意不能放在外⾯Stringsql="select_id,name,age,tallfromu_userwhere_id=?";Cursorcursor=db.rawQuery(sql,newString[]{String.valueOf(userid)});if(cursor.moveToNext()){returnnewUser(cursor.getInt(cursor.getColumnIndex("_id")),cursor.getString(cursor.getColumnIndex("name")),cursor.getInt(cursor.getColumnIndex("age")),cursor.getString(cursor.getColumnIndex("tall")));}returnnull;}/***显⽰⽤户*/publicCursorselect(){SQLiteDatabasedb=helper.getReadableDatabase();Cursorcursor=db.query("u_user",null,null,null,null,null,"_iddesc");returncursor;}}MainActivity.javapackagecom.chen.database;/***writer:ManMan*Email:1015082527@/doc/299973411.html**/import/doc/299973411.htmlerDAO;import/doc/299973411.htmler;importandroid.app.Activity;importandroid.database.Cursor;importandroid.os.Bundle;importandroid.util.Log;importandroid.view.View;importandroid.view.View.OnClickListener;importandroid.widget.Button;importandroid.widget.EditText;importandroid.widget.ListView;importandroid.widget.SimpleCursorAdapter;importandroid.widget.TextView;importandroid.widget.Toast;publicclassMainActivityextendsActivityimplementsOnClickListener{privatestaticfinalStringTAG="Add";privateEditTextedname,edage,edtall,id;privateButtonadd,deleteshow,show,iddelete,idupdate,idshow,deleteall;privateTextViewtedatashow;privateListViewdatashow;/**Calledwhentheactivityisfirstcreated.*/@OverridepublicvoidonCreate(BundlesavedInstanceState){super.onCreate(savedInstanceState);setContentView(/doc/299973411.htmlyout.main);edname=(EditText)findViewById(R.id.edname);edage=(EditText)findViewById(R.id.edage);edtall=(EditText)findViewById(R.id.edtall);id=(EditText)findViewById(R.id.id);tedatashow=(TextView)findViewById(R.id.tedatashow);datashow=(ListView)findViewById(R.id.datashow);add=(Button)findViewById(R.id.add);deleteshow=(Button)findViewById(R.id.deleteshow);show=(Button)findViewById(R.id.show);iddelete=(Button)findViewById(R.id.iddelete);idupdate=(Button)findViewById(R.id.idupdate);idshow=(Button)findViewById(R.id.idshow);deleteall=(Button)findViewById(R.id.deleteall);add.setOnClickListener(this);deleteshow.setOnClickListener(this);show.setOnClickListener(this);iddelete.setOnClickListener(this);idupdate.setOnClickListener(this);idshow.setOnClickListener(this);deleteall.setOnClickListener(this);}publicvoidonClick(Viewv){/**添加数据*/if(v==add){if(!id.getText().toString().equals(null)&&!edname.getText().toString().equals(null)&&!edage.getText().toString().equals(null)&&!edtall.getText().toString().equals(null)){try{UserDAOuserdao=newUserDAO(MainActivity.this);Useruser=newUser(Integer.valueOf(id.getText().toString()),edname.getText().toString(),Integer.valueOf(edage.getText().toString()),edtall.getText().toString());userdao.add(user);Toast.makeText(MainActivity.this,"成功添加！",Toast.LENGTH_LONG).show();tedatashow.setText("姓名:"+edname.getText().toString()+","+"年龄:"+Integer.valueOf(edage.getText().toString())+","+"⾝⾼:"+edtall.getText().toString()+",");//设置为空edage.setText("");edname.setText("");edtall.setText("");id.setText("");}catch(ExceptioneLog.i(TAG");Log.i(TAG,e.getMessage());}}elseif(id.getText().toString().equals(null)){Toast.makeText(MainActivity.this,"ID不能为空！",Toast.LENGTH_LONG).show();}}/**清除显⽰*/if(v==deleteshow){tedatashow.setText("");}/**全部显⽰*/if(v==show){try{UserDAOuserdao=newUserDAO(MainActivity.this);Cursorcursor=userdao.select();/**构建Listview适配器*/SimpleCursorAdapteradapter=newSimpleCursorAdapter(this,/doc/299973411.htmlyout.showuser,cursor,newStrin