android - Populating Expandable Listview with SQLite database -

i have sqlite database has columns id, homework, classname, date. have expandable listview. code works , creates expandable listview duplicates group titles.

the group names classname column, , child objects added group same classname. expandable listview takes each classname when need take each unique classname doesn't duplicate groups. here expandable listview adapter:

public class expandlistadapter extends cursortreeadapter {  sqlitehelper values; private layoutinflater minflator; context context; textview groupheader;  public expandlistadapter(cursor cursor, context context){     super(cursor, context);     this.context = context;     values = new sqlitehelper(context);     minflator = layoutinflater.from(context); }  @override public view newgroupview(context context, cursor cursor, boolean isexpanded,                          viewgroup parent){     final view view = minflator.inflate(r.layout.group_header, parent, false);      return view; }  public void bindgroupview(view view, context context, cursor cursor, boolean isexpanded){     groupheader = (textview) view.findviewbyid(r.id.group_name);     if(groupheader != null){         groupheader.settext(cursor.getstring(cursor.getcolumnindex("class")));     } }  @override public view newchildview(context context, cursor cursor,                          boolean islastchild, viewgroup parent){     final view view = minflator.inflate(r.layout.row_expandable, parent, false);      return view; }  @override public void bindchildview(view view, final context context, final cursor cursor,                           boolean islastchild){      textview homework = (textview) view.findviewbyid(r.id.homeworkdisplay1);     if(homework != null){         homework.settext(cursor.getstring(cursor.getcolumnindex(values.key_homework)));     }     textview date = (textview) view.findviewbyid(r.id.duedisplay1);     if(date != null){         date.settext(cursor.getstring(cursor.getcolumnindex(values.key_date)));     }     textview classes = (textview) view.findviewbyid(r.id.classdisplay1);     if(classes != null){         classes.settext(cursor.getstring(cursor.getcolumnindex(values.key_class)));     } }  @override protected  cursor getchildrencursor(cursor groupcursor){     values.open();     cursor childcursor = values.fetchchildren(groupcursor.getstring(groupcursor.getcolumnindex("class")));     childcursor.movetofirst();     values.close();     return childcursor; }  @override public void ongroupcollapsed(int groupposition){ }  @override public void ongroupexpanded(int groupposition){  }  } 

and here sqlitehelper class: public class sqlitehelper{

public static final int database_version = 1;  public static final string database_name = "homeworkmanager";  public static final string table_name = "homeworklist";  public static final string key_id = "_id"; public static final string key_homework = "homework"; public static final string key_date = "date"; public static final string key_class = "class"; private sqlitedatabase db; private dblisthelper myhelper; cursor db_cursor;  context context;   class dblisthelper extends sqliteopenhelper {   public dblisthelper(context context) {     super(context, database_name, null, database_version);  }  @override public void oncreate(sqlitedatabase db) {     string create_table = "create table " + table_name + " ("             + key_id + " integer primary key autoincrement, "             + key_homework + " text ,"             + key_date + " text ,"             + key_class + " text)";      db.execsql(create_table); }  @override public void onupgrade(sqlitedatabase db, int oldversion, int newversion) {     db.execsql("drop table if exists " + table_name);     oncreate(db); } }  public sqlitehelper(context context){     this.context = context; }  public sqlitehelper open() throws sqlexception{     myhelper = new dblisthelper(context);     db = myhelper.getreadabledatabase();     return this; }  public void close(){     if(myhelper != null){         myhelper.close();     } }  public long insertdata(string homework, string data, string classes){     contentvalues values = new contentvalues();     values.put(key_homework, homework);     values.put(key_date, data);     values.put(key_class, classes);      return db.insert(table_name, null, values); }  public cursor fetchgroup(){     string query = "select * homeworklist";     return db.rawquery(query, null); }  public cursor fetchchildren(string class_name){      string query = "select * homeworklist class = '" + class_name + "'";     cursor cursor = db.rawquery(query, null);      return cursor; }  public void remove(long id){     string whereclause = "_id=?";     string[] whereargs = new string[]{string.valueof(id)};     db.delete(table_name, whereclause, whereargs); }  } 

thanks in advance :)

hi there instead of passing cursor constructor public expandlistadapter(cursor cursor, context context){ why not replace list intended listview

public expandlistadapter(context context, list parent, list child){ wont have fetch data in every view prevent data being duplicated