android - Retrieve data from database and display them to screen -

i want display data database screen in grip view not working. when ran nothing happens no error or log

here code on mainactivity:

db db = new db(this);      // reading contacts     log.d("reading: ", "reading contacts..");     list<contact> contacts = db.getallcontacts();      (contact cn : contacts) {         string log = "id: "+cn.getid()+" ,name: " + cn.getname() + " ,time: " + cn.gettime();         // writing contacts log         log.d("name: ", log);      }      db.getallcontacts();      gridview = (gridview) findviewbyid(r.id.gridview1);     arrayadapter<string> adapter = new arrayadapter<string>(this,             android.r.layout.simple_list_item_1, arrayofname);     gridview.setadapter(adapter);      gridview.setonitemclicklistener(new adapterview.onitemclicklistener() {         public void onitemclick(adapterview<?> parent, view v,                                 int position, long id) {             toast.maketext(getapplicationcontext(),                     ((textview) v).gettext(), toast.length_short).show();         }     }); 

and here code on db:

//getting contacts1     public list<contact> getallcontacts() {     list<contact> contactlist = new arraylist<contact>();     // select query     string selectquery = "select  * " + table_contacts;      sqlitedatabase db = this.getwritabledatabase();     cursor cursor = db.rawquery(selectquery, null);      // looping through rows , adding list     if (cursor.movetofirst()) {         {             contact contact = new contact();             contact.setid(integer.parseint(cursor.getstring(0)));             contact.setname(cursor.getstring(1));             contact.settime(integer.parseint(cursor.getstring(2)));             // adding contact list             contactlist.add(contact);         } while (cursor.movetonext());     }      // return contact list     return contactlist; } 

i not sure excatly problem believe in mainactivity, in advance!

arrayofname not initialized anywhere, think should fill in first loop. no need second call getallcontacts.