java - Can not delete the note from the list and from the database in my note app for Android -

in note app android, if press long on note chose "delete" delete note, note still exists in list, after close app return it, note gone!

• hint: uses oncontextitemselected method show "delete" option.

how can delete note list , database?!

the mainactivity class contains oncontextitemselected method:

    package com.twitter.i_droidi.mynotes;  import android.app.alertdialog; import android.content.context; import android.content.dialoginterface; import android.content.intent; import android.support.v7.app.actionbaractivity; import android.os.bundle; import android.view.contextmenu; import android.view.layoutinflater; import android.view.menu; import android.view.menuinflater; import android.view.menuitem; import android.view.view; import android.view.viewgroup; import android.widget.adapterview; import android.widget.arrayadapter; import android.widget.listview; import android.widget.textview; import android.widget.toast; import java.util.list;  public class mainactivity extends actionbaractivity implements adapterview.onitemclicklistener {      listview lv;     notesdatasource nds;     list<notesmodel> noteslist;      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);          nds = new notesdatasource(this);         lv = (listview) findviewbyid(r.id.lv);          nds.open();         noteslist = nds.getallnotes();         nds.close();          string[] notes = new string[noteslist.size()];          (int = 0; < noteslist.size(); i++) {             notes[i] = noteslist.get(i).gettitle();         }          arrayadapter<string> adapter = new arrayadapter<string>(mainactivity.this, android.r.layout.simple_list_item_1,                 android.r.id.text1, notes);         lv.setadapter(adapter);          registerforcontextmenu(lv);         lv.setonitemclicklistener(this);     }      @override     public void onitemclick(adapterview<?> parent, view view, int position, long id) {         intent nview = new intent(this, second2.class);         nview.putextra("id", noteslist.get(position).getid());         nview.addflags(intent.flag_activity_clear_top);         startactivity(nview);     }      @override     public void oncreatecontextmenu(contextmenu menu, view v, contextmenu.contextmenuinfo menuinfo) {         menuinflater inflater = getmenuinflater();         inflater.inflate(r.menu.menu_delete, menu);         super.oncreatecontextmenu(menu, v, menuinfo);     }      @override     public boolean oncontextitemselected(menuitem item) {         switch (item.getitemid()) {             case r.id.delete:                 nds.open();                 nds.deletenote("id"); // check...!!!                 nds.close();                 toast ndelete = toast.maketext(this, r.string.deleted, toast.length_long);                 ndelete.show();         }         return super.oncontextitemselected(item);     }      @override     public boolean oncreateoptionsmenu(menu menu) {         menuinflater inflater = getmenuinflater();         inflater.inflate(r.menu.menu_main, menu);         return true;     }      @override     public boolean onoptionsitemselected(menuitem item) {         switch (item.getitemid()) {             case r.id.mainmenunewnote:                 intent nnote = new intent(this, second.class);                 startactivity(nnote);                 return true;              case r.id.mainmenuabout:                 alertdialog.builder aboutdialog = new alertdialog.builder(this);                 aboutdialog.settitle(getstring(r.string.about_title));                 aboutdialog.setmessage(r.string.about_body);                 aboutdialog.seticon(r.drawable.my_notes);                 aboutdialog.setpositivebutton(r.string.ok, new dialoginterface.onclicklistener() {                     @override                     public void onclick(dialoginterface aboutdialog, int witch) {                         // not anything.                     }                 });                  aboutdialog.show();                 return true;              case r.id.mainmenuexit:                 alertdialog.builder exdialog = new alertdialog.builder(this);                 exdialog.settitle(r.string.exit_title);                 exdialog.setmessage(r.string.exit_body);                 exdialog.seticon(r.drawable.my_notes);                 exdialog.setnegativebutton(r.string.yes, new dialoginterface.onclicklistener() {                     @override                     public void onclick(dialoginterface exdialog, int which) {                         finish();                     }                 });                 exdialog.setpositivebutton(r.string.no, new dialoginterface.onclicklistener() {                     @override                     public void onclick(dialoginterface exdialog, int which) {                         // not anything.                     }                 });                  exdialog.show();                 return true;         }         return super.onoptionsitemselected(item);     } } 

the db class:

    package com.twitter.i_droidi.mynotes;  import android.content.context; import android.database.sqlite.sqlitedatabase; import android.database.sqlite.sqliteopenhelper;  public class db extends sqliteopenhelper {      private static final string db_name = "mynotes";     private static final int db_version = 1;      public static final string table_name = "mynotes";     public static final string id = "id";     public static final string title = "title";     public static final string body = "body";      private static final string db_create = "create table " + table_name + " (" + id + " integer primary key autoincrement, " +             title + " text not null, " + body + " text not null)";      public db(context context) {         super(context, db_name, null, db_version);     }      @override     public void oncreate(sqlitedatabase db) {         db.execsql(db_create);     }      @override     public void onupgrade(sqlitedatabase db, int oldversion, int newversion) {         db.execsql("drop table if exists " + table_name);         oncreate(db);     } } 

the notesdatasource class:

    package com.twitter.i_droidi.mynotes;  import android.content.contentvalues; import android.content.context; import android.database.cursor; import android.database.sqlite.sqlitedatabase; import android.util.log; import java.util.arraylist; import java.util.list;  public class notesdatasource {      db mydb;     sqlitedatabase sql;      string[] getallcolumns = new string[]{db.id, db.title, db.body};      public notesdatasource(context context) {         mydb = new db(context);     }      public void open() {         try {             sql = mydb.getwritabledatabase();         } catch (exception ex) {             log.d("error in database!", ex.getmessage());         }     }      public void close() {         sql.close();     }      public void createnote(string title, string body) {         contentvalues note = new contentvalues();         note.put(mydb.title, title);         note.put(mydb.body, body);         sql.insert(mydb.table_name, null, note);     }      public notesmodel getnote(int id) {         notesmodel note = new notesmodel();          cursor cursor = sql.rawquery("select * " + db.table_name + " " + db.id + " = ?", new string[]{id + ""});          if (cursor.getcount() > 0) {             cursor.movetofirst();             note.setid(cursor.getint(0));             note.settitle(cursor.getstring(1));             note.setbody(cursor.getstring(2));             cursor.close();         }         return note;     }      public void updatenote(int id, string title, string body) {         contentvalues note = new contentvalues();         note.put(mydb.title, title);         note.put(mydb.body, body);         sql.update(mydb.table_name, note, mydb.id + " = " + id, null);     }      public void deletenote(object id) {         sql.delete(mydb.table_name, mydb.id + " = " + id, null);     }      public list<notesmodel> getallnotes() {         list<notesmodel> noteslist = new arraylist<notesmodel>();          stringbuffer selectquery = new stringbuffer();         selectquery.append("select * "+ mydb.table_name +"");          cursor cursor = sql.rawquery(selectquery.tostring(), null);          if(cursor != null && cursor.movetofirst()) {             {                 notesmodel notes = new notesmodel();                 notes.setid(cursor.getint(0));                 notes.settitle(cursor.getstring(1));                 notes.setbody(cursor.getstring(2));                  noteslist.add(notes);              } while (cursor.movetonext());         }         cursor.close();         return noteslist;     } } 

after removing item database remove deleted item

string[] notes 

by using

notes.remove(position); 

nd call

adapter.notifydatasetchanged();