java - Add item on RecycleView Android -

i'm trying add item on recycleview this:

i have object called image

public class image{    public string name;    public string url; } 

when click on button add new item, code this:

 @override     public void additemonlist(string url) {         adapter.additem(new imageobject("aaaaaa", r.drawable.close_button));     } 

that method inserts on list.

public void additem(imageobject imageobject) {         itemlist.add(imageobject);         notifydatasetchanged();     } 

my problem when click first time in additem onbindviewholder doesn't iterate list when check in debug mod getitemcount correct! if try add item after first time work well.

mainactivity

public class mainactivity extends appcompatactivity implements recyclerviewclicklistener, onstartdraglistener {     private recyclerviewadapter adapter;     private arraylist<imageobject> listviewitems;     private recyclerview recyclerview;     private itemtouchhelper itemtouchhelper;       @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);           recyclerview = (recyclerview) findviewbyid(r.id.recycler_view);          recyclerview.sethasfixedsize(true);          staggeredgridlayoutmanager staggeredlayoutmanager = new staggeredgridlayoutmanager(3, 1);         recyclerview.setlayoutmanager(staggeredlayoutmanager);          list<imageobject> staggered = getlistitemdata();          adapter = new recyclerviewadapter(this, staggered);         recyclerview.setadapter(adapter);          itemtouchhelper.callback callback = new simpleitemtouchhelpercallback(adapter);         itemtouchhelper = new itemtouchhelper(callback);         itemtouchhelper.attachtorecyclerview(recyclerview);      }      private list<imageobject> getlistitemdata() {          listviewitems = new arraylist<imageobject>();         listviewitems.add(new imageobject("alkane", r.drawable.one));         listviewitems.add(new imageobject("ethane", r.drawable.two));         listviewitems.add(new imageobject("alkyne", r.drawable.three));         listviewitems.add(new imageobject("benzene", r.drawable.four));         listviewitems.add(new imageobject("alkane", r.drawable.one));         listviewitems.add(new imageobject("ethane", r.drawable.two));         listviewitems.add(new imageobject("alkyne", r.drawable.three));         listviewitems.add(new imageobject("benzene", r.drawable.four));         listviewitems.add(new imageobject("alkane", r.drawable.one));         listviewitems.add(new imageobject("ethane", r.drawable.two));         listviewitems.add(new imageobject("alkyne", r.drawable.three));         listviewitems.add(new imageobject("benzene", r.drawable.four));          return listviewitems;     }       @override     public void addbuttonclicked() {         fragmentmanager fm = getsupportfragmentmanager();         alertfragment.newinstance(this).show(fm, "dialog");     }      @override     public void additemonlist(string url) {         adapter.additem(new imageobject("aaaaaa", r.drawable.close_button));     }      @override     public void onstartdrag(recyclerview.viewholder viewholder) {         itemtouchhelper.startdrag(viewholder);     } } 

my adapter

public class recyclerviewadapter extends recyclerview.adapter<recyclerviewadapter.viewholders> implements itemtouchhelperadapter {      private list<imageobject> itemlist;     private mainactivity mainactivity;     private recyclerviewclicklistener recyclelistener;     private onstartdraglistener dragstartlistener;      public recyclerviewadapter(mainactivity mainactivity, list<imageobject> itemlist) {         this.itemlist = itemlist;         this.mainactivity = mainactivity;         this.recyclelistener = mainactivity;         this.dragstartlistener = mainactivity;      }      @override     public viewholders oncreateviewholder(viewgroup parent, int viewtype) {          view layoutview;          switch (viewtype) {             case 1:                 layoutview = layoutinflater.from(parent.getcontext()).inflate(r.layout.add_item_list, null);                  break;             default:                 layoutview = layoutinflater.from(parent.getcontext()).inflate(r.layout.item_list, null);                 break;         }          return new viewholders(layoutview);     }      @override     public void onbindviewholder(final viewholders holder, final int position) {          switch (holder.getitemviewtype()) {             case 1:                 configureviewholderadditem(holder, position);                 break;              case 0:                 configuredefaultviewholder(holder, position);                 break;         }       }      private void configureviewholderadditem(final viewholders holder, final int position) {         holder.additemlayout = holder.itemview.findviewbyid(r.id.add_item_layout);         holder.additemlayout.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view view) {                 recyclelistener.addbuttonclicked();             }         });     }      private void configuredefaultviewholder(final viewholders holder, final int position) {         log.e("test", "position - " + position);         log.e("test", "name  - " + itemlist.get(position).getname());         holder.itemlayout = holder.itemview.findviewbyid(r.id.main_layout);         holder.removeitembutton = holder.itemview.findviewbyid(r.id.remove_item_button);         holder.itemlayout.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view view) {                 itemlist.remove(holder.getlayoutposition());                 notifyitemremoved(holder.getlayoutposition());                 notifyitemrangechanged(holder.getlayoutposition(), itemlist.size());             }         });         holder.itemlayout.setbackgroundresource(itemlist.get(position).getphoto());         holder.itemlayout.setontouchlistener(new view.ontouchlistener() {             @override             public boolean ontouch(view v, motionevent event) {                 if (event.getaction() == motionevent.action_down) {                     dragstartlistener.onstartdrag(holder);                 }                 return false;             }         });         //resizethefirstposition(holder, position);     }      private void resizethefirstposition(viewholders holder, int position) {         if (position == 0) {             int dimensionindp = (int) typedvalue.applydimension(typedvalue.complex_unit_dip,                     200, mainactivity.getresources().getdisplaymetrics());             holder.itemlayout.getlayoutparams().height = dimensionindp;             holder.itemlayout.getlayoutparams().width = dimensionindp;             holder.itemlayout.requestlayout();         }     }       public void additem(imageobject imageobject) {         itemlist.add(imageobject);         notifydatasetchanged();     }      @override     public int getitemviewtype(int position) {         return position == itemlist.size() - 1 ? 1 : 0;     }      @override     public int getitemcount() {         return this.itemlist.size();     }      @override     public boolean onitemmove(int fromposition, int toposition) {         collections.swap(itemlist, fromposition, toposition);         notifyitemmoved(fromposition, toposition);         return true;     }      @override     public void onitemdismiss(int position) {         itemlist.remove(position);         notifyitemremoved(position);     }       public class viewholders extends recyclerview.viewholder implements view.onclicklistener,             itemtouchhelperviewholder {          private imageview removeitembutton;         private imageview additembutton;         private framelayout additemlayout;         private relativelayout itemlayout;           public viewholders(view itemview) {             super(itemview);         }           @override         public void onclick(view view) {             itemlist.remove(getlayoutposition());             //notifyitemremoved(getlayoutposition());             notifyitemrangechanged(getlayoutposition(), itemlist.size());             toast.maketext(mainactivity, "removed item- " + getlayoutposition(), toast.length_short).show();         }          @override         public void onitemselected() {             itemview.setbackgroundcolor(color.ltgray);         }          @override         public void onitemclear() {             itemview.setbackgroundcolor(0);         }     } 

finally, fixed this. don't know why change how insert on list

old code:

public void additem(imageobject imageobject) {         itemlist.add(imageobject);         notifydatasetchanged(); } 

new code:

public void additem(imageobject imageobject) {     itemlist.add(itemlist.size() - 1, imageobject);     notifydatasetchanged(); }