anroid--Database Sqlite--sqliteopenhelper+sqlitedatabase

1.SQLite Lightweight . DP files are used in mobile phones

Lightweight, embedded relational data model.

Sqliteopenhelper

Responsible for creating open updates close database

Create a data table

Sqlitedatabase

Execute SQL statement

Increase the data table. By deleting. Change. Check.

<span style= "FONT-SIZE:18PX;" >package com.example.jreduch08.sqlitedemo.entity;/** * Created by the peak of the cupola on 2016/8/22.    */public class User {private int UserId;    private String name;    Private String pwd;    Private String age;    Private String img;    Public String GetName () {return name;    } public void SetName (String name) {this.name = name;    } public int getUserId () {return UserId;    } public void Setuserid (int userid) {userid = userid;    } public String Getpwd () {return pwd;    } public void SetPwd (String pwd) {this.pwd = pwd;    } public String Getage () {return age;    public void Setage (String age) {this.age = age;  } @Override Public String toString () {return "user{" + "userid=" + UserId + ",  Name= ' + name + ' \ ' + ', pwd= ' + pwd + ' \ ' + ', age= ' + age + ' + ', Img= ' " + img + ' \ ' + '} ';    } public String getimg () {return img;    } public void Setimg (String img) {this.img = img; }}</span>

<span style= "FONT-SIZE:18PX;" >package Com.example.jreduch08.sqlitedemo.entity;import Android.content.contentvalues;import Android.content.context;import Android.database.cursor;import Android.database.sqlite.sqlitedatabase;import Com.example.jreduch08.sqlitedemo.mydbhelper;import java.util.arraylist;import java.util.List;/** * Created by the peak of the cupola on 2016/8/22.    */public class Userdao {private Mydbhelper mydbhelper;    Public Userdao (Context context) {Mydbhelper =new mydbhelper (context);        }//Insert data public void Insert (user user) {sqlitedatabase db= mydbhelper.getwritabledatabase ();        Contentvalues cv=new contentvalues ();        Cv.put ("Name", User.getname ());        Cv.put ("pwd", user.getpwd ());        Cv.put ("Age", User.getage ());        Cv.put ("img", User.getimg ());        Db.insert ("info", NULL,CV);    Db.close ();        }//Query a data public User Searchuser (String id) {sqlitedatabase db=mydbhelper.getreadabledatabase (); Cursor cs= Db.query ("Info ", NULL," _id=?        ", new String[]{id},null,null,null);        User User=null;            if (Cs.movetonext ()) {user=new user ();            User.setuserid (Cs.getint (Cs.getcolumnindex ("_id"));            User.setname (Cs.getstring (Cs.getcolumnindex ("name"));            User.setpwd (Cs.getstring (Cs.getcolumnindex ("pwd"));            User.setage (Cs.getstring (Cs.getcolumnindex ("Age"));        User.setimg (Cs.getstring (Cs.getcolumnindex ("img"));        } cs.close ();        Db.close ();    return user;        }//Query all data public List search () {sqlitedatabase db=mydbhelper.getreadabledatabase ();        Cursor cs= db.query ("info", null,null,null,null,null,null);        User User=null;     List<user> list=new arraylist<> ();         while (Cs.movetonext ()) {user=new user ();         User.setuserid (Cs.getint (Cs.getcolumnindex ("_id"));         User.setname (Cs.getstring (Cs.getcolumnindex ("name")); User.setpwd (Cs.getstring (Cs.getcolumnindex ("PWD ")));        User.setage (Cs.getstring (Cs.getcolumnindex ("Age"));         User.setimg (Cs.getstring (Cs.getcolumnindex ("img"));     List.add (user);        } cs.close ();        Db.close ();    return list;       }//Delete all data public void Delete () {sqlitedatabase db=mydbhelper.getreadabledatabase ();        Db.delete ("info", null,null);    Db.close ();        }//delete a data public void DeleteUser (String id) {sqlitedatabase db=mydbhelper.getreadabledatabase ();        Db.delete ("info", "_id=?", New String[]{id});    Db.close ();        }//Modify data public void Updata (user user) {sqlitedatabase db=mydbhelper.getreadabledatabase ();        Contentvalues cv=new contentvalues ();        Cv.put ("Name", User.getname ());        Cv.put ("pwd", user.getpwd ());        Cv.put ("Age", User.getage ());        Cv.put ("img", User.getimg ());        String id=string.valueof (User.getuserid ());    Db.update ("info", CV, "_id=?", New String[]{id}); }}</span>

<span style= "FONT-SIZE:18PX;" >package Com.example.jreduch08.sqlitedemo;import Android.content.context;import Android.database.sqlite.sqlitedatabase;import android.database.sqlite.sqliteopenhelper;/** * Created by the peak of cupola on 2016/ 8/22.    */public class Mydbhelper extends sqliteopenhelper{//private final String DBNAME = "user.db";    Private final String table_name = "INFO";    Private final String info_colum_id = "_id";//Column name before private final string info_colum_name = "name";    Private final String info_colum_pwd = "PWD";    Private final String info_colum_age = "Age";    Private final String info_colum_img = "IMG";   Public Mydbhelper (Context context) {Super (context, "user.db", null,1); 1 version number.        Walk Onupgrade} public mydbhelper (context context, String name, Sqlitedatabase.cursorfactory factory, int version) {    Super (context, name, Factory, version); } @Override public void OnCreate (Sqlitedatabase SqlitedatabaSE) {StringBuilder sql=new StringBuilder ();        Sql.append ("Create table if not exists"),//+++++++++++++ space +++++++++++ sql.append (table_name+ "(");        Sql.append (info_colum_id+ "Integer primary Key AutoIncrement,");         Sql.append (info_colum_name+ "varchar (10),");        Sql.append (info_colum_pwd+ "varchar (10),");        Sql.append (info_colum_age+ "varchar (10),");        Sql.append (info_colum_img+ "varchar (10)");        Sql.append (")");    Sqlitedatabase.execsql (Sql.tostring ());  } @Override public void Onupgrade (sqlitedatabase sqlitedatabase, int i, int i1) {String sql= "drop table if        Exists "+table_name;        Sqlitedatabase.execsql (SQL);    OnCreate (sqlitedatabase); }}</span>

<span style= "FONT-SIZE:18PX;" >package Com.example.jreduch08.sqlitedemo;import Android.os.bundle;import Android.support.v7.app.appcompatactivity;import Android.view.view;import Android.widget.adapterview;import Android.widget.arrayadapter;import Android.widget.button;import Android.widget.edittext;import Android.widget.spinner;import Android.widget.textview;import Android.widget.toast;import Com.example.jreduch08.R; Import Com.example.jreduch08.sqlitedemo.entity.user;import Com.example.jreduch08.sqlitedemo.entity.UserDao; Import Java.util.arraylist;import Java.util.list;public class Sqllitetestactivity extends Appcompatactivity {private    EditText name,age,pwd;    Private Button button1,button2,button3,button4,button5;   Private TextView TV;    Private Spinner sp;    Private Userdao Userdao;        @Override protected void OnCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate);        Setcontentview (r.layout.activity_sqllite_test); Name= (EditText) findViewbyid (R.id.name);       Age= (EditText) Findviewbyid (r.id.age);        Pwd= (EditText) Findviewbyid (R.ID.PWD);        button1= (Button) Findviewbyid (R.id.button1);        Button2= (Button) Findviewbyid (R.id.button2);        button3= (Button) Findviewbyid (R.id.button3);        button4= (Button) Findviewbyid (R.ID.BUTTON4);        button5= (Button) Findviewbyid (R.ID.BUTTON5);        sp= (Spinner) Findviewbyid (R.ID.SP);        tv= (TextView) Findviewbyid (r.id.tv);        Userdao=new Userdao (this);                Button1.setonclicklistener (New View.onclicklistener () {@Override public void OnClick (view view) {                User User=new user ();                User.setname (Name.gettext (). toString ());                User.setage (Age.gettext (). toString ());                User.setpwd (Pwd.gettext (). toString ());                Userdao.insert (user);            Toast.maketext (Getbasecontext (), "added success", Toast.length_short). Show ();        }        }); Button2.setonclickListener (New View.onclicklistener () {@Override public void OnClick (view view) {List                <User> List=userdao.search ();                Tv.settext (List.tostring ());            List mydata=new ArrayList ();                              for (User u:list) {Mydata.add (U.getuserid () + ":" +u.getname ()); } arrayadapter aa=new Arrayadapter (Getbasecontext (), Android.                R.layout. Simple_list_item_1,mydata);            Sp.setadapter (AA);        }        });  Modify Button3.setonclicklistener (new View.onclicklistener () {@Override public void OnClick (view view) {String        Str=sp.getselecteditem (). toString ();            if (!str.equals ("")) {String id = str.split (":") [0];            User User=userdao.searchuser (ID);            User.setname (Name.gettext (). toString ());            User.setpwd (Pwd.gettext (). toString ());    User.setage (Age.gettext (). toString ());        Userdao.updata (user);  }    }}); Button4.setonclicklistener (New View.onclicklistener () {@Override public void OnClick (view view) {Stri          Ng Str=sp.getselecteditem (). toString ();              if (!str.equals ("")) {String id=str.split (":") [0];          Userdao.deleteuser (ID);        }      }  });                Button5.setonclicklistener (New View.onclicklistener () {@Override public void OnClick (view view) {            Userdao.delete ();        }        }); Sp.setonitemselectedlistener (New Adapterview.onitemselectedlistener () {@Override public void Onitem Selected (adapterview<?> adapterview, view view, int I, long l) {String str= Sp.getselecteditem (). toSt                Ring ();                 if (!str.equals ("")) {String id=str.split (":") [0];                    User user= userdao.searchuser (ID);                Name.settext (User.getname (). toString ());    Age.settext (User.getage (). toString ());                Pwd.settext (User.getpwd (). toString ());            }} @Override public void onnothingselected (adapterview<?> adapterview) {    }        }); }}</span>

<span style= "FONT-SIZE:18PX;" ><?xml version= "1.0" encoding= "Utf-8"? ><relativelayout xmlns:android= "http://schemas.android.com/apk/ Res/android "xmlns:tools=" Http://schemas.android.com/tools "android:layout_width=" Match_parent "android:layout_he    ight= "Match_parent" tools:context= "com.example.jreduch08.sqlitedemo.SqlliteTestActivity" ><linearlayout Android:layout_width= "Match_parent" android:layout_height= "match_parent" android:orientation= "vertical" > & Lt EditText android:layout_width= "match_parent" android:layout_height= "wrap_content" android:id= "@+id/na Me "android:hint=" Please enter the name "/> <edittext android:layout_width=" Match_parent "Android:lay out_height= "Wrap_content" android:id= "@+id/pwd" android:hint= "Please enter password"/> <edittext and Roid:layout_width= "Match_parent" android:layout_height= "wrap_content" android:id= "@+id/age" android:h Int= "Please enter age "/> <linearlayout android:layout_width=" match_parent "android:layout_height=" Wrap_cont            Ent "android:orientation=" horizontal "> <button android:layout_width=" wrap_content "            android:layout_height= "Wrap_content" android:id= "@+id/button1" android:text= "new"            /> <button android:layout_width= "wrap_content" android:layout_height= "Wrap_content" Android:id= "@+id/button2" android:text= "Query"/> <button android:la            Yout_width= "Wrap_content" android:layout_height= "wrap_content" android:id= "@+id/button3" android:text= "Modify"/> <button android:layout_width= "Wrap_content" Android:lay out_height= "Wrap_content" android:id= "@+id/button4" android:text= "delete"/> </linea Rlayout> <button android:layout_width= "match_parent" android:layout_height= "wrap_content" android:id= "@+id/button5" android:text= "Delete all"/> <textview android:layout_width= "Match_parent" Android:layout_h eight= "Wrap_content" android:id= "@+id/tv" android:text= "Result:"/> <spinner Android:layo Ut_width= "Match_parent" android:layout_height= "wrap_content" android:id= "@+id/sp" > </spinne R></linearlayout></relativelayout></span>

anroid--Database Sqlite--sqliteopenhelper+sqlitedatabase