Use SQLite database in Android (ii) Add and remove checks

Defining interfaces

Package Com.example.android_db.service;import Java.util.list;import Java.util.map;public interface PersonService { Public    Boolean Addperson (object[] params);                                      public boolean Deleteperson (object[] params);                                      public boolean Updateperson (object[] params);                                      Public map<string,string> Viewperson (string[] selectionargs);                                      Public list<map<string,string>> listpersonmaps (string[] selectionargs);

Implementing the interface:

Package Com.example.android_db.dao;import Java.util.arraylist;import Java.util.hashmap;import java.util.List; Import Java.util.map;import Android.content.context;import Android.database.cursor;import Android.database.sqlite.sqlitedatabase;import Com.example.android_db.db.dbopenhelper;import com.example.android_    Db.service.personservice;public class Persondao implements Personservice {private Dbopenhelper helper = null; Public Persondao (Context context) {//TODO auto-generated constructor stub helper = new Dbopenhelper (Contex    T); } @Override public Boolean Addperson (object[] params) {//TODO auto-generated method Stub boolean fla        g = false;        Implements the ability to add deletes and modify queries to the database sqlitedatabase = null;            try {String sql = "INSERT into person (name,address,sex) VALUES (?,?,?)";            Database = Helper.getwritabledatabase ();//implementation of write operations on Databases database.execsql (SQL, params);        Flag = true; } catch (ExcePtion e) {//Todo:handle exception e.printstacktrace ();            }finally{if (database!=null) {database.close ();    }} return flag; } @Override public Boolean Deleteperson (object[] params) {//TODO auto-generated Method Stub Boolean        Flag = false;        Sqlitedatabase database = null;            try {String sql = "Delete from the person where id =?";            Database = Helper.getwritabledatabase ();            Database.execsql (sql, params);        Flag = true;                } catch (Exception e) {//Todo:handle Exception}finally{if (database!=null) {            Database.close ();    }} return flag; } @Override public Boolean Updateperson (object[] params) {//TODO auto-generated Method Stub Boolean        Flag = false;        Sqlitedatabase database = null; try {String sql = "Update person set NamE =? , address =?, sex =? WHERE id =?            ";            Database = Helper.getwritabledatabase ();            Database.execsql (sql, params);        Flag = true;                } catch (Exception e) {//Todo:handle Exception}finally{if (database!=null) {            Database.close ();    }} return flag; } @Override public map<string, string> Viewperson (string[] selectionargs) {map<string,string> ma        p = new hashmap<string, string> ();        Sqlitedatabase database = null;            try {String sql = "SELECT * from the person where id =?";            Database = Helper.getreadabledatabase ();            cursor cursor = database.rawquery (sql, Selectionargs);            Gets the number of columns in the database int colums = Cursor.getcolumncount (); while (Cursor.movetonext ()) {for (int i=0;i<colums;i++) {String cols_name = cursor.getc                    Olumnname (i); String ColS_value = cursor.getstring (Cursor.getcolumnindex (cols_name));                    if (cols_value==null) {cols_value = "";                } map.put (Cols_name, Cols_value); }}} catch (Exception e) {//Todo:handle Exception}finally{if (database            !=null) {database.close ();    }} return map; } @Override public list<map<string, string>> listpersonmaps (string[] selectionargs) {//TODO Aut o-generated method Stub list<map<string,string>> List = new Arraylist<map<string,string>> ()        ;        String sql = "SELECT * from person";        Sqlitedatabase database = null;            try {database = Helper.getreadabledatabase ();            cursor cursor = database.rawquery (sql, Selectionargs);            int colums = Cursor.getcolumncount ();              while (Cursor.movetonext ()) {  map<string,string> map = new hashmap<string, string> ();                    for (int i=0;i<colums;i++) {String cols_name = cursor.getcolumnname (i);                    String Cols_value = cursor.getstring (Cursor.getcolumnindex (cols_name));                    if (cols_value==null) {cols_value= "";                } map.put (Cols_name, Cols_value);            } list.add (map);                }} catch (Exception e) {//Todo:handle Exception}finally{if (database!=null) {            Database.close ();    }} return list; }}

To implement Sqliteopenhelper subclasses

Package Com.example.android_db.db;import Android.content.context;import Android.database.DatabaseErrorHandler; Import Android.database.sqlite.sqlitedatabase;import Android.database.sqlite.sqlitedatabase.cursorfactory;import Android.database.sqlite.sqliteopenhelper;public class Dbopenhelper extends Sqliteopenhelper {private static String Nam        E = "mydb.db";//indicates the name of the database private static int version = 2;//indicates the version number of the database public Dbopenhelper (context context) {    Super (context, name, null, version); }//When the database is created, it is executed for the first time, completing the creation of tables on the database @Override public void onCreate (Sqlitedatabase db) {//TODO Auto-genera  Ted method stubs//Supported data types: Integer data, String type, date type, binary data type, String sql = "CREATE table person (ID integer PRIMARY key        Autoincrement,name varchar (+), address varchar (64)) ";    Db.execsql (SQL);  } @Override public void Onupgrade (sqlitedatabase db, int oldversion, int newversion) {//TODO auto-generated Method stub String sql = "Alter TABLe person Add sex varchar (8) ";    Db.execsql (SQL); }}

Test class:

Package Com.example.android_db.test;import Java.util.list;import Java.util.map;import com.example.android_ Db.dao.persondao;import Com.example.android_db.db.dbopenhelper;import com.example.android_ Db.service.personservice;import Android.test.androidtestcase;import Android.util.log;public class MyTest extends androidtestcase {public MyTest () {//TODO auto-generated constructor stubs} public void Createdb (        {Dbopenhelper helper = new Dbopenhelper (GetContext ());    Helper.getwritabledatabase ();        } public void Insertdb () {Personservice service = new Persondao (GetContext ());        Object[] params = {"Reese", "Guangxi", "female"};        Boolean flag = Service.addperson (params);    SYSTEM.OUT.PRINTLN ("--->>" +flag);        } public void Deletedb () {Personservice service = new Persondao (GetContext ());        Object[] params = {1};        Boolean flag = Service.deleteperson (params);    SYSTEM.OUT.PRINTLN ("--->>" +flag);      }     public void UpdateDB () {Personservice service = new Persondao (GetContext ());        Object[] params = {"Harry", "Shanghai", "Ominous", "3"};    Service.updateperson (params);        } public void Viewdb () {Personservice service = new Persondao (GetContext ());        String[] Selectionargs = {"3"};        map<string, string> map = Service.viewperson (Selectionargs);    LOG.I ("Test", "-->>" +map.tostring ());                   } public void Listdb () {Personservice service = new Persondao (GetContext ());        list<map<string,string>> list = Service.listpersonmaps (null);    LOG.I ("Test", "-->>" +list.tostring ()); }}